Hello.
As presented at this year's Cauldron, I rewrote current switch expansion to
support
multiple algorithms (jump table and bit-test) that can be used just for a
fraction
of cases. Balanced decision tree is built on top of that. I decided to do a
bigger
refactoring and put all there 3 mentioned algorithm to its own class.
There's a bigger change in jump_table_cluster::can_be_handled where the
constant 10 (3 respectively)
is compared to number of handled values, and not number of cases. Later one is
wrong in my opinion.
There are some numbers for cc1plus:
$ bloaty ./objdir2/gcc/cc1plus -- ./objdir/gcc/cc1plus
VM SIZE FILE SIZE
++++++++++++++ GROWING ++++++++++++++
+19% +1.32Mi .rodata +1.32Mi +19%
[ = ] 0 .symtab +7.38Ki +0.5%
[ = ] 0 .strtab +5.18Ki +0.2%
[ = ] 0 .debug_info +743 +0.0%
+0.0% +712 .eh_frame +712 +0.0%
+0.1% +440 .eh_frame_hdr +440 +0.1%
[ = ] 0 .debug_aranges +80 +0.1%
+0.0% +67 .dynstr +67 +0.0%
[ = ] 0 .debug_str +6 +0.0%
-------------- SHRINKING --------------
-1.2% -214Ki .text -214Ki -1.2%
[ = ] 0 .debug_loc -66.7Ki -0.1%
[ = ] 0 .debug_line -14.0Ki -0.2%
[ = ] 0 .debug_ranges -9.56Ki -0.1%
-6.8% -3 [Unmapped] -375 -14.4%
[ = ] 0 .debug_abbrev -46 -0.0%
+3.8% +1.11Mi TOTAL +1.03Mi +0.5%
So it growth and can be easily explained:
insn-attrtab.o:
VM SIZE FILE SIZE
++++++++++++++ GROWING ++++++++++++++
[ = ] 0 .rela.rodata +2.00Mi +215%
+214% +682Ki .rodata +682Ki +214%
[ = ] 0 .rela.debug_loc +29.3Ki +36%
+32% +1.91Ki .eh_frame +1.91Ki +32%
[ = ] 0 .debug_loc +37 +5.6%
[ = ] 0 .debug_str +2 +0.0%
-------------- SHRINKING --------------
-50.1% -63.3Ki .text -63.3Ki -50.1%
[ = ] 0 .debug_line -1.71Ki -10.4%
[ = ] 0 .rela.debug_info -768 -0.3%
[ = ] 0 .rela.text -624 -0.8%
[ = ] 0 .rela.debug_ranges -384 -2.7%
[ = ] 0 .debug_info -87 -0.2%
[ = ] 0 [Unmapped] -2 -8.7%
+137% +621Ki TOTAL +2.63Mi +139%
It's caused by:
...
;; GIMPLE switch case clusters: JT(2710):-1-5090
;; GIMPLE switch case clusters: JT(2710):-1-5090
;; GIMPLE switch case clusters: JT(2967):-1-5090
;; GIMPLE switch case clusters: JT(1033):-1-5017
...
so there are many switch statements with very reasonable density.
and
insn-dfatab.o: +13% +99.4Ki TOTAL +455Ki +14%
insn-latencytab.o: +19% +136Ki TOTAL +609Ki +20%
There shouldn't be any fallout other from what I mentioned in previous email
that is
a prerequisite for this patch.
Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
I'm still planning to come with some numbers and stats. Will do that next week.
Martin
>From db7ad52eb5d65e41d617fb3ff10ab1bc2cef8d04 Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Wed, 20 Sep 2017 15:22:04 +0200
Subject: [PATCH] Implement smart multiple switch expansion algorithms.
gcc/ChangeLog:
2017-09-29 Martin Liska <mli...@suse.cz>
* tree-switch-conversion.c (MAX_CASE_BIT_TESTS): Remove and move
to header file.
(hoist_edge_and_branch_if_true): Move to ...
(bit_test_cluster::hoist_edge_and_branch_if_true): ... this.
(expand_switch_using_bit_tests_p): Remove.
(struct case_bit_test): Move to header file.
(case_bit_test_cmp): Rename to case_bit_test::cmp.
(emit_case_bit_tests): Move to bit_test_cluster::emit.
(struct switch_conv_info): Transform to switch_conversion class.
(collect_switch_conv_info): Move to ...
(switch_conversion::collect): ... this.
(check_range): Move to ...
(switch_conversion::check_range): ... this.
(check_all_empty_except_final): Likewise.
(switch_conversion::check_all_empty_except_final): Likewise.
(check_final_bb): Likewise.
(switch_conversion::check_final_bb): Likewise.
(create_temp_arrays): Likewise.
(switch_conversion::create_temp_arrays): Likewise.
(free_temp_arrays): Remove.
(gather_default_values): Move to ...
(switch_conversion::gather_default_values): ... this.
(build_constructors): Likewise.
(switch_conversion::build_constructors): Likewise.
(array_value_type): Likewise.
(switch_conversion::array_value_type): Likewise.
(build_one_array): Likewise.
(switch_conversion::build_one_array): Likewise.
(build_arrays): Likewise.
(switch_conversion::build_arrays): Likewise.
(gen_def_assigns): Likewise.
(switch_conversion::gen_def_assigns): Likewise.
(prune_bbs): Likewise.
(switch_conversion::prune_bbs): Likewise.
(fix_phi_nodes): Likewise.
(switch_conversion::fix_phi_nodes): Likewise.
(gen_inbound_check): Likewise.
(switch_conversion::gen_inbound_check): Likewise.
(constructor_contains_same_values_p): Likewise.
(switch_conversion::contains_same_values_p): Likewise.
(process_switch): Likewise.
(switch_conversion::expand): Likewise.
(switch_conversion::~switch_conversion): New function.
(pass_convert_switch::execute): Use new functions.
(group_cluster::~group_cluster): New function.
(struct case_node): Move to header file.
(jump_table_cluster::jump_table_cluster): New function.
(jump_table_cluster::emit): Likewise.
(jump_table_cluster::find_jump_tables): Likewise.
(jump_table_cluster::can_be_handled): Likewise.
(jump_table_cluster::is_beneficial): Likewise.
(bit_test_cluster::bit_test_cluster): Likewise.
(bit_test_cluster::find_bit_tests): Likewise.
(bit_test_cluster::can_be_handled): Likewise.
(bit_test_cluster::is_beneficial): Likewise.
(case_bit_test::cmp): Likewise.
(bit_test_cluster::emit): Likewise.
(emit_case_nodes): Move to ...
(switch_decision_tree::emit_case_nodes): ... this.
(case_values_threshold): Move to
jump_table_cluster::case_values_threshold.
(reset_out_edges_aux): Move to
switch_decision_tree::reset_out_edges_aux.
(compute_cases_per_edge): Move to ...
(switch_decision_tree::compute_cases_per_edge): ... this.
(add_case_node): Remove.
(switch_decision_tree::analyze_switch_statement): New function.
(dump_case_nodes): Move to ...
(switch_decision_tree::dump_case_nodes): ... this.
(balance_case_nodes): Move to ...
(switch_decision_tree::balance_case_nodes): ... this.
(expand_switch_as_decision_tree_p): Remove.
(fix_phi_operands_for_edge): Move to ...
(switch_decision_tree::fix_phi_operands_for_edges): ... this.
(emit_jump): Move to ...
(switch_decision_tree::emit_jump): ... this.
(try_switch_expansion): Move to ...
(switch_decision_tree::try_switch_expansion): ... this.
(emit_case_decision_tree): Remove.
(record_phi_operand_mapping): Move to ...
(switch_decision_tree::record_phi_operand_mapping): ... this.
(switch_decision_tree::emit): New function.
(pass_lower_switch::execute): Make 2 instancens: for -O0 and
other optimization levels.
(emit_cmp_and_jump_insns): Move to ...
(switch_decision_tree::emit_cmp_and_jump_insns): ... this.
(conditional_probability): Remove.
* tree-switch-conversion.h: New file.
* vec.h (vl_ptr>::reverse): New function.
* passes.def: Add pass_lower_switch_O0.
* stmt.c (emit_case_dispatch_table): Fix tree folding.
(expand_case): Likewise.
gcc/testsuite/ChangeLog:
2017-10-05 Martin Liska <mli...@suse.cz>
* gcc.dg/ipa/ipa-icf-13.c: Update scanned pattern.
---
gcc/passes.def | 2 +-
gcc/stmt.c | 17 +-
gcc/testsuite/gcc.dg/ipa/ipa-icf-13.c | 3 +-
gcc/tree-switch-conversion.c | 2304 ++++++++++++++-------------------
gcc/tree-switch-conversion.h | 806 ++++++++++++
gcc/vec.h | 14 +
6 files changed, 1791 insertions(+), 1355 deletions(-)
create mode 100644 gcc/tree-switch-conversion.h
diff --git a/gcc/passes.def b/gcc/passes.def
index bb371d9bde5..ea0c6d37fa1 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -395,8 +395,8 @@ along with GCC; see the file COPYING3. If not see
NEXT_PASS (pass_lower_vaarg);
NEXT_PASS (pass_lower_vector);
NEXT_PASS (pass_lower_complex_O0);
- NEXT_PASS (pass_lower_switch_O0);
NEXT_PASS (pass_sancov_O0);
+ NEXT_PASS (pass_lower_switch_O0);
NEXT_PASS (pass_asan_O0);
NEXT_PASS (pass_tsan_O0);
NEXT_PASS (pass_sanopt);
diff --git a/gcc/stmt.c b/gcc/stmt.c
index 92bd209ad64..4743975a48a 100644
--- a/gcc/stmt.c
+++ b/gcc/stmt.c
@@ -776,18 +776,18 @@ emit_case_dispatch_table (tree index_expr, tree index_type,
for (unsigned j = 0; j < case_list.length (); j++)
{
simple_case_node *n = &case_list[j];
+ tree index_type_unsigned = signed_or_unsigned_type_for (1, index_type);
/* Compute the low and high bounds relative to the minimum
value since that should fit in a HOST_WIDE_INT while the
actual values may not. */
- HOST_WIDE_INT i_low
- = tree_to_uhwi (fold_build2 (MINUS_EXPR, index_type,
+ unsigned HOST_WIDE_INT i_low
+ = tree_to_uhwi (fold_build2 (MINUS_EXPR, index_type_unsigned,
n->m_low, minval));
- HOST_WIDE_INT i_high
- = tree_to_uhwi (fold_build2 (MINUS_EXPR, index_type,
+ unsigned HOST_WIDE_INT i_high
+ = tree_to_uhwi (fold_build2 (MINUS_EXPR, index_type_unsigned,
n->m_high, minval));
- HOST_WIDE_INT i;
- for (i = i_low; i <= i_high; i ++)
+ for (unsigned HOST_WIDE_INT i = i_low; i <= i_high; i ++)
labelvec[i]
= gen_rtx_LABEL_REF (Pmode, label_rtx (n->m_code_label));
}
@@ -913,7 +913,10 @@ expand_case (gswitch *stmt)
maxval = fold_convert (index_type, CASE_LOW (elt));
/* Compute span of values. */
- range = fold_build2 (MINUS_EXPR, index_type, maxval, minval);
+ tree index_type_unsigned = signed_or_unsigned_type_for (1, index_type);
+ range = fold_build2 (MINUS_EXPR, index_type_unsigned,
+ fold_convert (index_type_unsigned, maxval),
+ fold_convert (index_type_unsigned, minval));
/* Listify the labels queue and gather some numbers to decide
how to expand this switch(). */
diff --git a/gcc/testsuite/gcc.dg/ipa/ipa-icf-13.c b/gcc/testsuite/gcc.dg/ipa/ipa-icf-13.c
index 09d817c4030..3e59f8e0933 100644
--- a/gcc/testsuite/gcc.dg/ipa/ipa-icf-13.c
+++ b/gcc/testsuite/gcc.dg/ipa/ipa-icf-13.c
@@ -190,4 +190,5 @@ int main(int argc, char **argv)
/* { dg-final { scan-ipa-dump "Semantic equality hit:s1->s2" "icf" } } */
/* { dg-final { scan-ipa-dump "Semantic equality hit:nsd_different_result->nsd_different_result2" "icf" } } */
/* { dg-final { scan-ipa-dump "Semantic equality hit:gcd->nsd" "icf" } } */
-/* { dg-final { scan-ipa-dump "Equal symbols: 3" "icf" } } */
+/* { dg-final { scan-ipa-dump "Semantic equality hit:CSWTCH.*->CSWTCH.*" "icf" } } */
+/* { dg-final { scan-ipa-dump "Equal symbols: 4" "icf" } } */
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index f67531b2620..6e928afc49c 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -49,629 +49,79 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
#include "alloc-pool.h"
#include "target.h"
#include "tree-into-ssa.h"
-
/* ??? For lang_hooks.types.type_for_mode, but is there a word_mode
type in the GIMPLE type system that is language-independent? */
#include "langhooks.h"
-
-/* Maximum number of case bit tests.
- FIXME: This should be derived from PARAM_CASE_VALUES_THRESHOLD and
- targetm.case_values_threshold(), or be its own param. */
-#define MAX_CASE_BIT_TESTS 3
-
-/* Split the basic block at the statement pointed to by GSIP, and insert
- a branch to the target basic block of E_TRUE conditional on tree
- expression COND.
-
- It is assumed that there is already an edge from the to-be-split
- basic block to E_TRUE->dest block. This edge is removed, and the
- profile information on the edge is re-used for the new conditional
- jump.
-
- The CFG is updated. The dominator tree will not be valid after
- this transformation, but the immediate dominators are updated if
- UPDATE_DOMINATORS is true.
-
- Returns the newly created basic block. */
-
-static basic_block
-hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip,
- tree cond, edge e_true,
- bool update_dominators)
-{
- tree tmp;
- gcond *cond_stmt;
- edge e_false;
- basic_block new_bb, split_bb = gsi_bb (*gsip);
- bool dominated_e_true = false;
-
- gcc_assert (e_true->src == split_bb);
-
- if (update_dominators
- && get_immediate_dominator (CDI_DOMINATORS, e_true->dest) == split_bb)
- dominated_e_true = true;
-
- tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL,
- /*before=*/true, GSI_SAME_STMT);
- cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE);
- gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT);
-
- e_false = split_block (split_bb, cond_stmt);
- new_bb = e_false->dest;
- redirect_edge_pred (e_true, split_bb);
-
- e_true->flags &= ~EDGE_FALLTHRU;
- e_true->flags |= EDGE_TRUE_VALUE;
-
- e_false->flags &= ~EDGE_FALLTHRU;
- e_false->flags |= EDGE_FALSE_VALUE;
- e_false->probability = e_true->probability.invert ();
- e_false->count = split_bb->count - e_true->count;
- new_bb->count = e_false->count;
-
- if (update_dominators)
- {
- if (dominated_e_true)
- set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb);
- set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb);
- }
-
- return new_bb;
-}
-
-
-/* Return true if a switch should be expanded as a bit test.
- RANGE is the difference between highest and lowest case.
- UNIQ is number of unique case node targets, not counting the default case.
- COUNT is the number of comparisons needed, not counting the default case. */
-
-static bool
-expand_switch_using_bit_tests_p (tree range,
- unsigned int uniq,
- unsigned int count, bool speed_p)
-{
- return (((uniq == 1 && count >= 3)
- || (uniq == 2 && count >= 5)
- || (uniq == 3 && count >= 6))
- && lshift_cheap_p (speed_p)
- && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
- && compare_tree_int (range, 0) > 0);
-}
-
-/* Implement switch statements with bit tests
-
-A GIMPLE switch statement can be expanded to a short sequence of bit-wise
-comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)"
-where CST and MINVAL are integer constants. This is better than a series
-of compare-and-banch insns in some cases, e.g. we can implement:
-
- if ((x==4) || (x==6) || (x==9) || (x==11))
-
-as a single bit test:
-
- if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11)))
-
-This transformation is only applied if the number of case targets is small,
-if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are
-performed in "word_mode".
-
-The following example shows the code the transformation generates:
-
- int bar(int x)
- {
- switch (x)
- {
- case '0': case '1': case '2': case '3': case '4':
- case '5': case '6': case '7': case '8': case '9':
- case 'A': case 'B': case 'C': case 'D': case 'E':
- case 'F':
- return 1;
- }
- return 0;
- }
-
-==>
-
- bar (int x)
- {
- tmp1 = x - 48;
- if (tmp1 > (70 - 48)) goto L2;
- tmp2 = 1 << tmp1;
- tmp3 = 0b11111100000001111111111;
- if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2;
- L1:
- return 1;
- L2:
- return 0;
- }
-
-TODO: There are still some improvements to this transformation that could
-be implemented:
-
-* A narrower mode than word_mode could be used if that is cheaper, e.g.
- for x86_64 where a narrower-mode shift may result in smaller code.
-
-* The compounded constant could be shifted rather than the one. The
- test would be either on the sign bit or on the least significant bit,
- depending on the direction of the shift. On some machines, the test
- for the branch would be free if the bit to test is already set by the
- shift operation.
-
-This transformation was contributed by Roger Sayle, see this e-mail:
- http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html
-*/
-
-/* A case_bit_test represents a set of case nodes that may be
- selected from using a bit-wise comparison. HI and LO hold
- the integer to be tested against, TARGET_EDGE contains the
- edge to the basic block to jump to upon success and BITS
- counts the number of case nodes handled by this test,
- typically the number of bits set in HI:LO. The LABEL field
- is used to quickly identify all cases in this set without
- looking at label_to_block for every case label. */
-
-struct case_bit_test
-{
- wide_int mask;
- edge target_edge;
- tree label;
- int bits;
-};
-
-/* Comparison function for qsort to order bit tests by decreasing
- probability of execution. Our best guess comes from a measured
- profile. If the profile counts are equal, break even on the
- number of case nodes, i.e. the node with the most cases gets
- tested first.
-
- TODO: Actually this currently runs before a profile is available.
- Therefore the case-as-bit-tests transformation should be done
- later in the pass pipeline, or something along the lines of
- "Efficient and effective branch reordering using profile data"
- (Yang et. al., 2002) should be implemented (although, how good
- is a paper is called "Efficient and effective ..." when the
- latter is implied by the former, but oh well...). */
-
-static int
-case_bit_test_cmp (const void *p1, const void *p2)
-{
- const struct case_bit_test *const d1 = (const struct case_bit_test *) p1;
- const struct case_bit_test *const d2 = (const struct case_bit_test *) p2;
-
- if (d2->target_edge->count < d1->target_edge->count)
- return -1;
- if (d2->target_edge->count > d1->target_edge->count)
- return 1;
- if (d2->bits != d1->bits)
- return d2->bits - d1->bits;
-
- /* Stabilize the sort. */
- return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label);
-}
-
-/* Expand a switch statement by a short sequence of bit-wise
- comparisons. "switch(x)" is effectively converted into
- "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
- integer constants.
+#include "tree-switch-conversion.h"
- INDEX_EXPR is the value being switched on.
+using namespace tree_switch_conversion;
- MINVAL is the lowest case value of in the case nodes,
- and RANGE is highest value minus MINVAL. MINVAL and RANGE
- are not guaranteed to be of the same type as INDEX_EXPR
- (the gimplifier doesn't change the type of case label values,
- and MINVAL and RANGE are derived from those values).
- MAXVAL is MINVAL + RANGE.
-
- There *MUST* be MAX_CASE_BIT_TESTS or less unique case
- node targets. */
-
-static void
-emit_case_bit_tests (gswitch *swtch, tree index_expr,
- tree minval, tree range, tree maxval)
+switch_conversion::switch_conversion (): m_final_bb (NULL), m_other_count (),
+ m_constructors (NULL), m_default_values (NULL),
+ m_arr_ref_first (NULL), m_arr_ref_last (NULL),
+ m_reason (NULL), m_default_case_nonstandard (false)
{
- struct case_bit_test test[MAX_CASE_BIT_TESTS] = { {} };
- unsigned int i, j, k;
- unsigned int count;
-
- basic_block switch_bb = gimple_bb (swtch);
- basic_block default_bb, new_default_bb, new_bb;
- edge default_edge;
- bool update_dom = dom_info_available_p (CDI_DOMINATORS);
-
- vec<basic_block> bbs_to_fix_dom = vNULL;
-
- tree index_type = TREE_TYPE (index_expr);
- tree unsigned_index_type = unsigned_type_for (index_type);
- unsigned int branch_num = gimple_switch_num_labels (swtch);
-
- gimple_stmt_iterator gsi;
- gassign *shift_stmt;
-
- tree idx, tmp, csui;
- tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1);
- tree word_mode_zero = fold_convert (word_type_node, integer_zero_node);
- tree word_mode_one = fold_convert (word_type_node, integer_one_node);
- int prec = TYPE_PRECISION (word_type_node);
- wide_int wone = wi::one (prec);
-
- /* Get the edge for the default case. */
- tmp = gimple_switch_default_label (swtch);
- default_bb = label_to_block (CASE_LABEL (tmp));
- default_edge = find_edge (switch_bb, default_bb);
-
- /* Go through all case labels, and collect the case labels, profile
- counts, and other information we need to build the branch tests. */
- count = 0;
- for (i = 1; i < branch_num; i++)
- {
- unsigned int lo, hi;
- tree cs = gimple_switch_label (swtch, i);
- tree label = CASE_LABEL (cs);
- edge e = find_edge (switch_bb, label_to_block (label));
- for (k = 0; k < count; k++)
- if (e == test[k].target_edge)
- break;
-
- if (k == count)
- {
- gcc_checking_assert (count < MAX_CASE_BIT_TESTS);
- test[k].mask = wi::zero (prec);
- test[k].target_edge = e;
- test[k].label = label;
- test[k].bits = 1;
- count++;
- }
- else
- test[k].bits++;
-
- lo = tree_to_uhwi (int_const_binop (MINUS_EXPR,
- CASE_LOW (cs), minval));
- if (CASE_HIGH (cs) == NULL_TREE)
- hi = lo;
- else
- hi = tree_to_uhwi (int_const_binop (MINUS_EXPR,
- CASE_HIGH (cs), minval));
-
- for (j = lo; j <= hi; j++)
- test[k].mask |= wi::lshift (wone, j);
- }
-
- qsort (test, count, sizeof (*test), case_bit_test_cmp);
-
- /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of
- the minval subtractions, but it might make the mask constants more
- expensive. So, compare the costs. */
- if (compare_tree_int (minval, 0) > 0
- && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
- {
- int cost_diff;
- HOST_WIDE_INT m = tree_to_uhwi (minval);
- rtx reg = gen_raw_REG (word_mode, 10000);
- bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch));
- cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg,
- GEN_INT (-m)), speed_p);
- for (i = 0; i < count; i++)
- {
- rtx r = immed_wide_int_const (test[i].mask, word_mode);
- cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r),
- word_mode, speed_p);
- r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode);
- cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r),
- word_mode, speed_p);
- }
- if (cost_diff > 0)
- {
- for (i = 0; i < count; i++)
- test[i].mask = wi::lshift (test[i].mask, m);
- minval = build_zero_cst (TREE_TYPE (minval));
- range = maxval;
- }
- }
-
- /* We generate two jumps to the default case label.
- Split the default edge, so that we don't have to do any PHI node
- updating. */
- new_default_bb = split_edge (default_edge);
-
- if (update_dom)
- {
- bbs_to_fix_dom.create (10);
- bbs_to_fix_dom.quick_push (switch_bb);
- bbs_to_fix_dom.quick_push (default_bb);
- bbs_to_fix_dom.quick_push (new_default_bb);
- }
-
- /* Now build the test-and-branch code. */
-
- gsi = gsi_last_bb (switch_bb);
-
- /* idx = (unsigned)x - minval. */
- idx = fold_convert (unsigned_index_type, index_expr);
- idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx,
- fold_convert (unsigned_index_type, minval));
- idx = force_gimple_operand_gsi (&gsi, idx,
- /*simple=*/true, NULL_TREE,
- /*before=*/true, GSI_SAME_STMT);
-
- /* if (idx > range) goto default */
- range = force_gimple_operand_gsi (&gsi,
- fold_convert (unsigned_index_type, range),
- /*simple=*/true, NULL_TREE,
- /*before=*/true, GSI_SAME_STMT);
- tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range);
- new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom);
- if (update_dom)
- bbs_to_fix_dom.quick_push (new_bb);
- gcc_assert (gimple_bb (swtch) == new_bb);
- gsi = gsi_last_bb (new_bb);
-
- /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors
- of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */
- if (update_dom)
- {
- vec<basic_block> dom_bbs;
- basic_block dom_son;
-
- dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb);
- FOR_EACH_VEC_ELT (dom_bbs, i, dom_son)
- {
- edge e = find_edge (new_bb, dom_son);
- if (e && single_pred_p (e->dest))
- continue;
- set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb);
- bbs_to_fix_dom.safe_push (dom_son);
- }
- dom_bbs.release ();
- }
-
- /* csui = (1 << (word_mode) idx) */
- csui = make_ssa_name (word_type_node);
- tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one,
- fold_convert (word_type_node, idx));
- tmp = force_gimple_operand_gsi (&gsi, tmp,
- /*simple=*/false, NULL_TREE,
- /*before=*/true, GSI_SAME_STMT);
- shift_stmt = gimple_build_assign (csui, tmp);
- gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT);
- update_stmt (shift_stmt);
-
- /* for each unique set of cases:
- if (const & csui) goto target */
- for (k = 0; k < count; k++)
- {
- tmp = wide_int_to_tree (word_type_node, test[k].mask);
- tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp);
- tmp = force_gimple_operand_gsi (&gsi, tmp,
- /*simple=*/true, NULL_TREE,
- /*before=*/true, GSI_SAME_STMT);
- tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero);
- new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge,
- update_dom);
- if (update_dom)
- bbs_to_fix_dom.safe_push (new_bb);
- gcc_assert (gimple_bb (swtch) == new_bb);
- gsi = gsi_last_bb (new_bb);
- }
-
- /* We should have removed all edges now. */
- gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0);
-
- /* If nothing matched, go to the default label. */
- make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU);
-
- /* The GIMPLE_SWITCH is now redundant. */
- gsi_remove (&gsi, true);
-
- if (update_dom)
- {
- /* Fix up the dominator tree. */
- iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true);
- bbs_to_fix_dom.release ();
- }
}
-
-/*
- Switch initialization conversion
-
-The following pass changes simple initializations of scalars in a switch
-statement into initializations from a static array. Obviously, the values
-must be constant and known at compile time and a default branch must be
-provided. For example, the following code:
-
- int a,b;
-
- switch (argc)
- {
- case 1:
- case 2:
- a_1 = 8;
- b_1 = 6;
- break;
- case 3:
- a_2 = 9;
- b_2 = 5;
- break;
- case 12:
- a_3 = 10;
- b_3 = 4;
- break;
- default:
- a_4 = 16;
- b_4 = 1;
- break;
- }
- a_5 = PHI <a_1, a_2, a_3, a_4>
- b_5 = PHI <b_1, b_2, b_3, b_4>
-
-
-is changed into:
-
- static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4};
- static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16,
- 16, 16, 10};
-
- if (((unsigned) argc) - 1 < 11)
- {
- a_6 = CSWTCH02[argc - 1];
- b_6 = CSWTCH01[argc - 1];
- }
- else
- {
- a_7 = 16;
- b_7 = 1;
- }
- a_5 = PHI <a_6, a_7>
- b_b = PHI <b_6, b_7>
-There are further constraints. Specifically, the range of values across all
-case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default
-eight) times the number of the actual switch branches.
-
-This transformation was contributed by Martin Jambor, see this e-mail:
- http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */
-
-/* The main structure of the pass. */
-struct switch_conv_info
-{
- /* The expression used to decide the switch branch. */
- tree index_expr;
-
- /* The following integer constants store the minimum and maximum value
- covered by the case labels. */
- tree range_min;
- tree range_max;
-
- /* The difference between the above two numbers. Stored here because it
- is used in all the conversion heuristics, as well as for some of the
- transformation, and it is expensive to re-compute it all the time. */
- tree range_size;
-
- /* Basic block that contains the actual GIMPLE_SWITCH. */
- basic_block switch_bb;
-
- /* Basic block that is the target of the default case. */
- basic_block default_bb;
-
- /* The single successor block of all branches out of the GIMPLE_SWITCH,
- if such a block exists. Otherwise NULL. */
- basic_block final_bb;
-
- /* The probability of the default edge in the replaced switch. */
- profile_probability default_prob;
-
- /* The count of the default edge in the replaced switch. */
- profile_count default_count;
-
- /* Combined count of all other (non-default) edges in the replaced switch. */
- profile_count other_count;
-
- /* Number of phi nodes in the final bb (that we'll be replacing). */
- int phi_count;
-
- /* Array of default values, in the same order as phi nodes. */
- tree *default_values;
-
- /* Constructors of new static arrays. */
- vec<constructor_elt, va_gc> **constructors;
-
- /* Array of ssa names that are initialized with a value from a new static
- array. */
- tree *target_inbound_names;
-
- /* Array of ssa names that are initialized with the default value if the
- switch expression is out of range. */
- tree *target_outbound_names;
-
- /* VOP SSA_NAME. */
- tree target_vop;
-
- /* The first load statement that loads a temporary from a new static array.
- */
- gimple *arr_ref_first;
-
- /* The last load statement that loads a temporary from a new static array. */
- gimple *arr_ref_last;
-
- /* String reason why the case wasn't a good candidate that is written to the
- dump file, if there is one. */
- const char *reason;
-
- /* True if default case is not used for any value between range_min and
- range_max inclusive. */
- bool contiguous_range;
-
- /* True if default case does not have the required shape for other case
- labels. */
- bool default_case_nonstandard;
-
- /* Parameters for expand_switch_using_bit_tests. Should be computed
- the same way as in expand_case. */
- unsigned int uniq;
- unsigned int count;
-};
-
-/* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */
-
-static void
-collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info)
+void
+switch_conversion::collect (gswitch *swtch)
{
unsigned int branch_num = gimple_switch_num_labels (swtch);
tree min_case, max_case;
- unsigned int count, i;
+ unsigned int i;
edge e, e_default, e_first;
edge_iterator ei;
basic_block first;
- memset (info, 0, sizeof (*info));
+ m_switch = swtch;
/* The gimplifier has already sorted the cases by CASE_LOW and ensured there
is a default label which is the first in the vector.
Collect the bits we can deduce from the CFG. */
- info->index_expr = gimple_switch_index (swtch);
- info->switch_bb = gimple_bb (swtch);
- info->default_bb
+ m_index_expr = gimple_switch_index (swtch);
+ m_switch_bb = gimple_bb (swtch);
+ m_default_bb
= label_to_block (CASE_LABEL (gimple_switch_default_label (swtch)));
- e_default = find_edge (info->switch_bb, info->default_bb);
- info->default_prob = e_default->probability;
- info->default_count = e_default->count;
- FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
+ e_default = find_edge (m_switch_bb, m_default_bb);
+ m_default_prob = e_default->probability;
+ m_default_count = e_default->count;
+ FOR_EACH_EDGE (e, ei, m_switch_bb->succs)
if (e != e_default)
- info->other_count += e->count;
+ m_other_count += e->count;
/* Get upper and lower bounds of case values, and the covered range. */
min_case = gimple_switch_label (swtch, 1);
max_case = gimple_switch_label (swtch, branch_num - 1);
- info->range_min = CASE_LOW (min_case);
+ m_range_min = CASE_LOW (min_case);
if (CASE_HIGH (max_case) != NULL_TREE)
- info->range_max = CASE_HIGH (max_case);
+ m_range_max = CASE_HIGH (max_case);
else
- info->range_max = CASE_LOW (max_case);
+ m_range_max = CASE_LOW (max_case);
- info->contiguous_range = true;
- tree last = CASE_HIGH (min_case) ? CASE_HIGH (min_case) : info->range_min;
+ m_contiguous_range = true;
+ tree last = CASE_HIGH (min_case) ? CASE_HIGH (min_case) : m_range_min;
for (i = 2; i < branch_num; i++)
{
tree elt = gimple_switch_label (swtch, i);
wide_int w = last;
if (w + 1 != CASE_LOW (elt))
{
- info->contiguous_range = false;
+ m_contiguous_range = false;
break;
}
last = CASE_HIGH (elt) ? CASE_HIGH (elt) : CASE_LOW (elt);
}
- if (info->contiguous_range)
+ if (m_contiguous_range)
{
first = label_to_block (CASE_LABEL (gimple_switch_label (swtch, 1)));
- e_first = find_edge (info->switch_bb, first);
+ e_first = find_edge (m_switch_bb, first);
}
else
{
- first = info->default_bb;
+ first = m_default_bb;
e_first = e_default;
}
@@ -681,103 +131,91 @@ collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info)
if the range is contiguous and default case otherwise as
guess or its destination in case it is a forwarder block. */
if (! single_pred_p (e_first->dest))
- info->final_bb = e_first->dest;
+ m_final_bb = e_first->dest;
else if (single_succ_p (e_first->dest)
&& ! single_pred_p (single_succ (e_first->dest)))
- info->final_bb = single_succ (e_first->dest);
+ m_final_bb = single_succ (e_first->dest);
/* Require that all switch destinations are either that common
FINAL_BB or a forwarder to it, except for the default
case if contiguous range. */
- if (info->final_bb)
- FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
+ if (m_final_bb)
+ FOR_EACH_EDGE (e, ei, m_switch_bb->succs)
{
- if (e->dest == info->final_bb)
+ if (e->dest == m_final_bb)
continue;
if (single_pred_p (e->dest)
&& single_succ_p (e->dest)
- && single_succ (e->dest) == info->final_bb)
+ && single_succ (e->dest) == m_final_bb)
continue;
- if (e == e_default && info->contiguous_range)
+ if (e == e_default && m_contiguous_range)
{
- info->default_case_nonstandard = true;
+ m_default_case_nonstandard = true;
continue;
}
- info->final_bb = NULL;
+ m_final_bb = NULL;
break;
}
- info->range_size
- = int_const_binop (MINUS_EXPR, info->range_max, info->range_min);
+ m_range_size
+ = int_const_binop (MINUS_EXPR, m_range_max, m_range_min);
/* Get a count of the number of case labels. Single-valued case labels
simply count as one, but a case range counts double, since it may
require two compares if it gets lowered as a branching tree. */
- count = 0;
+ m_count = 0;
for (i = 1; i < branch_num; i++)
{
tree elt = gimple_switch_label (swtch, i);
- count++;
+ m_count++;
if (CASE_HIGH (elt)
&& ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt)))
- count++;
+ m_count++;
}
- info->count = count;
-
- /* Get the number of unique non-default targets out of the GIMPLE_SWITCH
- block. Assume a CFG cleanup would have already removed degenerate
- switch statements, this allows us to just use EDGE_COUNT. */
- info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1;
}
-/* Checks whether the range given by individual case statements of the SWTCH
- switch statement isn't too big and whether the number of branches actually
- satisfies the size of the new array. */
-
-static bool
-check_range (struct switch_conv_info *info)
+bool
+switch_conversion::check_range ()
{
- gcc_assert (info->range_size);
- if (!tree_fits_uhwi_p (info->range_size))
+ gcc_assert (m_range_size);
+ if (!tree_fits_uhwi_p (m_range_size))
{
- info->reason = "index range way too large or otherwise unusable";
+ m_reason = "index range way too large or otherwise unusable";
return false;
}
- if (tree_to_uhwi (info->range_size)
- > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO))
+ if (tree_to_uhwi (m_range_size)
+ > ((unsigned) m_count * SWITCH_CONVERSION_BRANCH_RATIO))
{
- info->reason = "the maximum range-branch ratio exceeded";
+ m_reason = "the maximum range-branch ratio exceeded";
return false;
}
return true;
}
-/* Checks whether all but the FINAL_BB basic blocks are empty. */
-
-static bool
-check_all_empty_except_final (struct switch_conv_info *info)
+bool
+switch_conversion::check_all_empty_except_final ()
{
- edge e, e_default = find_edge (info->switch_bb, info->default_bb);
+ edge e, e_default = find_edge (m_switch_bb, m_default_bb);
edge_iterator ei;
- FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
+ FOR_EACH_EDGE (e, ei, m_switch_bb->succs)
{
- if (e->dest == info->final_bb)
+ if (e->dest == m_final_bb)
continue;
if (!empty_block_p (e->dest))
{
- if (info->contiguous_range && e == e_default)
+ if (m_contiguous_range && e == e_default)
{
- info->default_case_nonstandard = true;
+ m_default_case_nonstandard = true;
continue;
}
- info->reason = "bad case - a non-final BB not empty";
+ m_reason = "bad case - a non-final BB not empty";
return false;
}
}
@@ -785,18 +223,13 @@ check_all_empty_except_final (struct switch_conv_info *info)
return true;
}
-/* This function checks whether all required values in phi nodes in final_bb
- are constants. Required values are those that correspond to a basic block
- which is a part of the examined switch statement. It returns true if the
- phi nodes are OK, otherwise false. */
-
-static bool
-check_final_bb (gswitch *swtch, struct switch_conv_info *info)
+bool
+switch_conversion::check_final_bb ()
{
gphi_iterator gsi;
- info->phi_count = 0;
- for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ m_phi_count = 0;
+ for (gsi = gsi_start_phis (m_final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gphi *phi = gsi.phi ();
unsigned int i;
@@ -804,16 +237,16 @@ check_final_bb (gswitch *swtch, struct switch_conv_info *info)
if (virtual_operand_p (gimple_phi_result (phi)))
continue;
- info->phi_count++;
+ m_phi_count++;
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
basic_block bb = gimple_phi_arg_edge (phi, i)->src;
- if (bb == info->switch_bb
+ if (bb == m_switch_bb
|| (single_pred_p (bb)
- && single_pred (bb) == info->switch_bb
- && (!info->default_case_nonstandard
+ && single_pred (bb) == m_switch_bb
+ && (!m_default_case_nonstandard
|| empty_block_p (bb))))
{
tree reloc, val;
@@ -841,25 +274,25 @@ check_final_bb (gswitch *swtch, struct switch_conv_info *info)
/* For contiguous range, we can allow non-constant
or one that needs relocation, as long as it is
only reachable from the default case. */
- if (bb == info->switch_bb)
- bb = info->final_bb;
- if (!info->contiguous_range || bb != info->default_bb)
+ if (bb == m_switch_bb)
+ bb = m_final_bb;
+ if (!m_contiguous_range || bb != m_default_bb)
{
- info->reason = reason;
+ m_reason = reason;
return false;
}
- unsigned int branch_num = gimple_switch_num_labels (swtch);
+ unsigned int branch_num = gimple_switch_num_labels (m_switch);
for (unsigned int i = 1; i < branch_num; i++)
{
- tree lab = CASE_LABEL (gimple_switch_label (swtch, i));
+ tree lab = CASE_LABEL (gimple_switch_label (m_switch, i));
if (label_to_block (lab) == bb)
{
- info->reason = reason;
+ m_reason = reason;
return false;
}
}
- info->default_case_nonstandard = true;
+ m_default_case_nonstandard = true;
}
}
}
@@ -868,44 +301,24 @@ check_final_bb (gswitch *swtch, struct switch_conv_info *info)
return true;
}
-/* The following function allocates default_values, target_{in,out}_names and
- constructors arrays. The last one is also populated with pointers to
- vectors that will become constructors of new arrays. */
-
-static void
-create_temp_arrays (struct switch_conv_info *info)
+void
+switch_conversion::create_temp_arrays ()
{
int i;
- info->default_values = XCNEWVEC (tree, info->phi_count * 3);
+ m_default_values = XCNEWVEC (tree, m_phi_count * 3);
/* ??? Macros do not support multi argument templates in their
argument list. We create a typedef to work around that problem. */
typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc;
- info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count);
- info->target_inbound_names = info->default_values + info->phi_count;
- info->target_outbound_names = info->target_inbound_names + info->phi_count;
- for (i = 0; i < info->phi_count; i++)
- vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1);
+ m_constructors = XCNEWVEC (vec_constructor_elt_gc, m_phi_count);
+ m_target_inbound_names = m_default_values + m_phi_count;
+ m_target_outbound_names = m_target_inbound_names + m_phi_count;
+ for (i = 0; i < m_phi_count; i++)
+ vec_alloc (m_constructors[i], tree_to_uhwi (m_range_size) + 1);
}
-/* Free the arrays created by create_temp_arrays(). The vectors that are
- created by that function are not freed here, however, because they have
- already become constructors and must be preserved. */
-
-static void
-free_temp_arrays (struct switch_conv_info *info)
-{
- XDELETEVEC (info->constructors);
- XDELETEVEC (info->default_values);
-}
-
-/* Populate the array of default values in the order of phi nodes.
- DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch
- if the range is non-contiguous or the default case has standard
- structure, otherwise it is the first non-default case instead. */
-
-static void
-gather_default_values (tree default_case, struct switch_conv_info *info)
+void
+switch_conversion::gather_default_values (tree default_case)
{
gphi_iterator gsi;
basic_block bb = label_to_block (CASE_LABEL (default_case));
@@ -913,46 +326,42 @@ gather_default_values (tree default_case, struct switch_conv_info *info)
int i = 0;
gcc_assert (CASE_LOW (default_case) == NULL_TREE
- || info->default_case_nonstandard);
+ || m_default_case_nonstandard);
- if (bb == info->final_bb)
- e = find_edge (info->switch_bb, bb);
+ if (bb == m_final_bb)
+ e = find_edge (m_switch_bb, bb);
else
e = single_succ_edge (bb);
- for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ for (gsi = gsi_start_phis (m_final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gphi *phi = gsi.phi ();
if (virtual_operand_p (gimple_phi_result (phi)))
continue;
tree val = PHI_ARG_DEF_FROM_EDGE (phi, e);
gcc_assert (val);
- info->default_values[i++] = val;
+ m_default_values[i++] = val;
}
}
-/* The following function populates the vectors in the constructors array with
- future contents of the static arrays. The vectors are populated in the
- order of phi nodes. SWTCH is the switch statement being converted. */
-
-static void
-build_constructors (gswitch *swtch, struct switch_conv_info *info)
+void
+switch_conversion::build_constructors ()
{
- unsigned i, branch_num = gimple_switch_num_labels (swtch);
- tree pos = info->range_min;
+ unsigned i, branch_num = gimple_switch_num_labels (m_switch);
+ tree pos = m_range_min;
tree pos_one = build_int_cst (TREE_TYPE (pos), 1);
for (i = 1; i < branch_num; i++)
{
- tree cs = gimple_switch_label (swtch, i);
+ tree cs = gimple_switch_label (m_switch, i);
basic_block bb = label_to_block (CASE_LABEL (cs));
edge e;
tree high;
gphi_iterator gsi;
int j;
- if (bb == info->final_bb)
- e = find_edge (info->switch_bb, bb);
+ if (bb == m_final_bb)
+ e = find_edge (m_switch_bb, bb);
else
e = single_succ_edge (bb);
gcc_assert (e);
@@ -960,15 +369,14 @@ build_constructors (gswitch *swtch, struct switch_conv_info *info)
while (tree_int_cst_lt (pos, CASE_LOW (cs)))
{
int k;
- gcc_assert (!info->contiguous_range);
- for (k = 0; k < info->phi_count; k++)
+ for (k = 0; k < m_phi_count; k++)
{
constructor_elt elt;
- elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min);
+ elt.index = int_const_binop (MINUS_EXPR, pos, m_range_min);
elt.value
- = unshare_expr_without_location (info->default_values[k]);
- info->constructors[k]->quick_push (elt);
+ = unshare_expr_without_location (m_default_values[k]);
+ m_constructors[k]->quick_push (elt);
}
pos = int_const_binop (PLUS_EXPR, pos, pos_one);
@@ -980,7 +388,7 @@ build_constructors (gswitch *swtch, struct switch_conv_info *info)
high = CASE_HIGH (cs);
else
high = CASE_LOW (cs);
- for (gsi = gsi_start_phis (info->final_bb);
+ for (gsi = gsi_start_phis (m_final_bb);
!gsi_end_p (gsi); gsi_next (&gsi))
{
gphi *phi = gsi.phi ();
@@ -994,9 +402,9 @@ build_constructors (gswitch *swtch, struct switch_conv_info *info)
{
constructor_elt elt;
- elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min);
+ elt.index = int_const_binop (MINUS_EXPR, pos, m_range_min);
elt.value = unshare_expr_without_location (val);
- info->constructors[j]->quick_push (elt);
+ m_constructors[j]->quick_push (elt);
pos = int_const_binop (PLUS_EXPR, pos, pos_one);
} while (!tree_int_cst_lt (high, pos)
@@ -1006,12 +414,8 @@ build_constructors (gswitch *swtch, struct switch_conv_info *info)
}
}
-/* If all values in the constructor vector are the same, return the value.
- Otherwise return NULL_TREE. Not supposed to be called for empty
- vectors. */
-
-static tree
-constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec)
+tree
+switch_conversion::contains_same_values_p (vec<constructor_elt, va_gc> *vec)
{
unsigned int i;
tree prev = NULL_TREE;
@@ -1027,15 +431,10 @@ constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec)
return prev;
}
-/* Return type which should be used for array elements, either TYPE's
- main variant or, for integral types, some smaller integral type
- that can still hold all the constants. */
-
-static tree
-array_value_type (gswitch *swtch, tree type, int num,
- struct switch_conv_info *info)
+tree
+switch_conversion::array_value_type (tree type, int num)
{
- unsigned int i, len = vec_safe_length (info->constructors[num]);
+ unsigned int i, len = vec_safe_length (m_constructors[num]);
constructor_elt *elt;
int sign = 0;
tree smaller_type;
@@ -1055,10 +454,10 @@ array_value_type (gswitch *swtch, tree type, int num,
if (GET_MODE_SIZE (type_mode) <= GET_MODE_SIZE (mode))
return type;
- if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32))
+ if (len < (optimize_bb_for_size_p (gimple_bb (m_switch)) ? 2 : 32))
return type;
- FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt)
+ FOR_EACH_VEC_SAFE_ELT (m_constructors[num], i, elt)
{
wide_int cst;
@@ -1104,49 +503,39 @@ array_value_type (gswitch *swtch, tree type, int num,
return smaller_type;
}
-/* Create an appropriate array type and declaration and assemble a static array
- variable. Also create a load statement that initializes the variable in
- question with a value from the static array. SWTCH is the switch statement
- being converted, NUM is the index to arrays of constructors, default values
- and target SSA names for this particular array. ARR_INDEX_TYPE is the type
- of the index of the new array, PHI is the phi node of the final BB that
- corresponds to the value that will be loaded from the created array. TIDX
- is an ssa name of a temporary variable holding the index for loads from the
- new array. */
-
-static void
-build_one_array (gswitch *swtch, int num, tree arr_index_type,
- gphi *phi, tree tidx, struct switch_conv_info *info)
+void
+switch_conversion::build_one_array (int num, tree arr_index_type,
+ gphi *phi, tree tidx)
{
tree name, cst;
gimple *load;
- gimple_stmt_iterator gsi = gsi_for_stmt (swtch);
- location_t loc = gimple_location (swtch);
+ gimple_stmt_iterator gsi = gsi_for_stmt (m_switch);
+ location_t loc = gimple_location (m_switch);
- gcc_assert (info->default_values[num]);
+ gcc_assert (m_default_values[num]);
name = copy_ssa_name (PHI_RESULT (phi));
- info->target_inbound_names[num] = name;
+ m_target_inbound_names[num] = name;
- cst = constructor_contains_same_values_p (info->constructors[num]);
+ cst = contains_same_values_p (m_constructors[num]);
if (cst)
load = gimple_build_assign (name, cst);
else
{
tree array_type, ctor, decl, value_type, fetch, default_type;
- default_type = TREE_TYPE (info->default_values[num]);
- value_type = array_value_type (swtch, default_type, num, info);
+ default_type = TREE_TYPE (m_default_values[num]);
+ value_type = array_value_type (default_type, num);
array_type = build_array_type (value_type, arr_index_type);
if (default_type != value_type)
{
unsigned int i;
constructor_elt *elt;
- FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt)
+ FOR_EACH_VEC_SAFE_ELT (m_constructors[num], i, elt)
elt->value = fold_convert (value_type, elt->value);
}
- ctor = build_constructor (array_type, info->constructors[num]);
+ ctor = build_constructor (array_type, m_constructors[num]);
TREE_CONSTANT (ctor) = true;
TREE_STATIC (ctor) = true;
@@ -1175,15 +564,11 @@ build_one_array (gswitch *swtch, int num, tree arr_index_type,
gsi_insert_before (&gsi, load, GSI_SAME_STMT);
update_stmt (load);
- info->arr_ref_last = load;
+ m_arr_ref_last = load;
}
-/* Builds and initializes static arrays initialized with values gathered from
- the SWTCH switch statement. Also creates statements that load values from
- them. */
-
-static void
-build_arrays (gswitch *swtch, struct switch_conv_info *info)
+void
+switch_conversion::build_arrays ()
{
tree arr_index_type;
tree tidx, sub, utype;
@@ -1191,84 +576,77 @@ build_arrays (gswitch *swtch, struct switch_conv_info *info)
gimple_stmt_iterator gsi;
gphi_iterator gpi;
int i;
- location_t loc = gimple_location (swtch);
+ location_t loc = gimple_location (m_switch);
- gsi = gsi_for_stmt (swtch);
+ gsi = gsi_for_stmt (m_switch);
/* Make sure we do not generate arithmetics in a subrange. */
- utype = TREE_TYPE (info->index_expr);
+ utype = TREE_TYPE (m_index_expr);
if (TREE_TYPE (utype))
utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1);
else
utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1);
- arr_index_type = build_index_type (info->range_size);
+ arr_index_type = build_index_type (m_range_size);
tidx = make_ssa_name (utype);
sub = fold_build2_loc (loc, MINUS_EXPR, utype,
- fold_convert_loc (loc, utype, info->index_expr),
- fold_convert_loc (loc, utype, info->range_min));
+ fold_convert_loc (loc, utype, m_index_expr),
+ fold_convert_loc (loc, utype, m_range_min));
sub = force_gimple_operand_gsi (&gsi, sub,
false, NULL, true, GSI_SAME_STMT);
stmt = gimple_build_assign (tidx, sub);
gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
update_stmt (stmt);
- info->arr_ref_first = stmt;
+ m_arr_ref_first = stmt;
- for (gpi = gsi_start_phis (info->final_bb), i = 0;
+ for (gpi = gsi_start_phis (m_final_bb), i = 0;
!gsi_end_p (gpi); gsi_next (&gpi))
{
gphi *phi = gpi.phi ();
if (!virtual_operand_p (gimple_phi_result (phi)))
- build_one_array (swtch, i++, arr_index_type, phi, tidx, info);
+ build_one_array (i++, arr_index_type, phi, tidx);
else
{
edge e;
edge_iterator ei;
- FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
+ FOR_EACH_EDGE (e, ei, m_switch_bb->succs)
{
- if (e->dest == info->final_bb)
+ if (e->dest == m_final_bb)
break;
- if (!info->default_case_nonstandard
- || e->dest != info->default_bb)
+ if (!m_default_case_nonstandard
+ || e->dest != m_default_bb)
{
e = single_succ_edge (e->dest);
break;
}
}
- gcc_assert (e && e->dest == info->final_bb);
- info->target_vop = PHI_ARG_DEF_FROM_EDGE (phi, e);
+ gcc_assert (e && e->dest == m_final_bb);
+ m_target_vop = PHI_ARG_DEF_FROM_EDGE (phi, e);
}
}
}
-/* Generates and appropriately inserts loads of default values at the position
- given by BSI. Returns the last inserted statement. */
-
-static gassign *
-gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info)
+gassign *
+switch_conversion::gen_def_assigns (gimple_stmt_iterator *gsi)
{
int i;
gassign *assign = NULL;
- for (i = 0; i < info->phi_count; i++)
+ for (i = 0; i < m_phi_count; i++)
{
- tree name = copy_ssa_name (info->target_inbound_names[i]);
- info->target_outbound_names[i] = name;
- assign = gimple_build_assign (name, info->default_values[i]);
+ tree name = copy_ssa_name (m_target_inbound_names[i]);
+ m_target_outbound_names[i] = name;
+ assign = gimple_build_assign (name, m_default_values[i]);
gsi_insert_before (gsi, assign, GSI_SAME_STMT);
update_stmt (assign);
}
return assign;
}
-/* Deletes the unused bbs and edges that now contain the switch statement and
- its empty branch bbs. BBD is the now dead BB containing the original switch
- statement, FINAL is the last BB of the converted switch statement (in terms
- of succession). */
-
-static void
-prune_bbs (basic_block bbd, basic_block final, basic_block default_bb)
+void
+switch_conversion::prune_bbs (basic_block bbd, basic_block final,
+ basic_block default_bb)
{
edge_iterator ei;
edge e;
@@ -1284,14 +662,8 @@ prune_bbs (basic_block bbd, basic_block final, basic_block default_bb)
delete_basic_block (bbd);
}
-/* Add values to phi nodes in final_bb for the two new edges. E1F is the edge
- from the basic block loading values from an array and E2F from the basic
- block loading default values. BBF is the last switch basic block (see the
- bbf description in the comment below). */
-
-static void
-fix_phi_nodes (edge e1f, edge e2f, basic_block bbf,
- struct switch_conv_info *info)
+void
+switch_conversion::fix_phi_nodes (edge e1f, edge e2f, basic_block bbf)
{
gphi_iterator gsi;
int i;
@@ -1302,41 +674,20 @@ fix_phi_nodes (edge e1f, edge e2f, basic_block bbf,
gphi *phi = gsi.phi ();
tree inbound, outbound;
if (virtual_operand_p (gimple_phi_result (phi)))
- inbound = outbound = info->target_vop;
+ inbound = outbound = m_target_vop;
else
{
- inbound = info->target_inbound_names[i];
- outbound = info->target_outbound_names[i++];
+ inbound = m_target_inbound_names[i];
+ outbound = m_target_outbound_names[i++];
}
add_phi_arg (phi, inbound, e1f, UNKNOWN_LOCATION);
- if (!info->default_case_nonstandard)
+ if (!m_default_case_nonstandard)
add_phi_arg (phi, outbound, e2f, UNKNOWN_LOCATION);
}
}
-/* Creates a check whether the switch expression value actually falls into the
- range given by all the cases. If it does not, the temporaries are loaded
- with default values instead. SWTCH is the switch statement being converted.
-
- bb0 is the bb with the switch statement, however, we'll end it with a
- condition instead.
-
- bb1 is the bb to be used when the range check went ok. It is derived from
- the switch BB
-
- bb2 is the bb taken when the expression evaluated outside of the range
- covered by the created arrays. It is populated by loads of default
- values.
-
- bbF is a fall through for both bb1 and bb2 and contains exactly what
- originally followed the switch statement.
-
- bbD contains the switch statement (in the end). It is unreachable but we
- still need to strip off its edges.
-*/
-
-static void
-gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
+void
+switch_conversion::gen_inbound_check ()
{
tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION);
tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION);
@@ -1351,30 +702,30 @@ gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
gimple_stmt_iterator gsi;
basic_block bb0, bb1, bb2, bbf, bbd;
edge e01 = NULL, e02, e21, e1d, e1f, e2f;
- location_t loc = gimple_location (swtch);
+ location_t loc = gimple_location (m_switch);
- gcc_assert (info->default_values);
+ gcc_assert (m_default_values);
- bb0 = gimple_bb (swtch);
+ bb0 = gimple_bb (m_switch);
- tidx = gimple_assign_lhs (info->arr_ref_first);
+ tidx = gimple_assign_lhs (m_arr_ref_first);
utype = TREE_TYPE (tidx);
/* (end of) block 0 */
- gsi = gsi_for_stmt (info->arr_ref_first);
+ gsi = gsi_for_stmt (m_arr_ref_first);
gsi_next (&gsi);
- bound = fold_convert_loc (loc, utype, info->range_size);
+ bound = fold_convert_loc (loc, utype, m_range_size);
cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE);
gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT);
update_stmt (cond_stmt);
/* block 2 */
- if (!info->default_case_nonstandard)
+ if (!m_default_case_nonstandard)
{
label2 = gimple_build_label (label_decl2);
gsi_insert_before (&gsi, label2, GSI_SAME_STMT);
- last_assign = gen_def_assigns (&gsi, info);
+ last_assign = gen_def_assigns (&gsi);
}
/* block 1 */
@@ -1382,7 +733,7 @@ gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
gsi_insert_before (&gsi, label1, GSI_SAME_STMT);
/* block F */
- gsi = gsi_start_bb (info->final_bb);
+ gsi = gsi_start_bb (m_final_bb);
label3 = gimple_build_label (label_decl3);
gsi_insert_before (&gsi, label3, GSI_SAME_STMT);
@@ -1390,10 +741,10 @@ gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
e02 = split_block (bb0, cond_stmt);
bb2 = e02->dest;
- if (info->default_case_nonstandard)
+ if (m_default_case_nonstandard)
{
bb1 = bb2;
- bb2 = info->default_bb;
+ bb2 = m_default_bb;
e01 = e02;
e01->flags = EDGE_TRUE_VALUE;
e02 = make_edge (bb0, bb2, EDGE_FALSE_VALUE);
@@ -1417,49 +768,49 @@ gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
remove_edge (e21);
}
- e1d = split_block (bb1, info->arr_ref_last);
+ e1d = split_block (bb1, m_arr_ref_last);
bbd = e1d->dest;
remove_edge (e1d);
- /* flags and profiles of the edge for in-range values */
- if (!info->default_case_nonstandard)
+ /* Flags and profiles of the edge for in-range values. */
+ if (!m_default_case_nonstandard)
e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE);
- e01->probability = info->default_prob.invert ();
- e01->count = info->other_count;
+ e01->probability = m_default_prob.invert ();
+ e01->count = m_other_count;
- /* flags and profiles of the edge taking care of out-of-range values */
+ /* Flags and profiles of the edge taking care of out-of-range values. */
e02->flags &= ~EDGE_FALLTHRU;
e02->flags |= EDGE_FALSE_VALUE;
- e02->probability = info->default_prob;
- e02->count = info->default_count;
+ e02->probability = m_default_prob;
+ e02->count = m_default_count;
- bbf = info->final_bb;
+ bbf = m_final_bb;
e1f = make_edge (bb1, bbf, EDGE_FALLTHRU);
e1f->probability = profile_probability::always ();
- e1f->count = info->other_count;
+ e1f->count = m_other_count;
- if (info->default_case_nonstandard)
+ if (m_default_case_nonstandard)
e2f = NULL;
else
{
e2f = make_edge (bb2, bbf, EDGE_FALLTHRU);
e2f->probability = profile_probability::always ();
- e2f->count = info->default_count;
+ e2f->count = m_default_count;
}
- /* frequencies of the new BBs */
+ /* Frequencies of the new BBs. */
bb1->frequency = EDGE_FREQUENCY (e01);
bb2->frequency = EDGE_FREQUENCY (e02);
- if (!info->default_case_nonstandard)
+ if (!m_default_case_nonstandard)
bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f);
/* Tidy blocks that have become unreachable. */
- prune_bbs (bbd, info->final_bb,
- info->default_case_nonstandard ? info->default_bb : NULL);
+ prune_bbs (bbd, m_final_bb,
+ m_default_case_nonstandard ? m_default_bb : NULL);
/* Fixup the PHI nodes in bbF. */
- fix_phi_nodes (e1f, e2f, bbf, info);
+ fix_phi_nodes (e1f, e2f, bbf);
/* Fix the dominator tree, if it is available. */
if (dom_info_available_p (CDI_DOMINATORS))
@@ -1467,7 +818,7 @@ gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
vec<basic_block> bbs_to_fix_dom;
set_immediate_dominator (CDI_DOMINATORS, bb1, bb0);
- if (!info->default_case_nonstandard)
+ if (!m_default_case_nonstandard)
set_immediate_dominator (CDI_DOMINATORS, bb2, bb0);
if (! get_immediate_dominator (CDI_DOMINATORS, bbf))
/* If bbD was the immediate dominator ... */
@@ -1485,96 +836,72 @@ gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
}
}
-/* The following function is invoked on every switch statement (the current one
- is given in SWTCH) and runs the individual phases of switch conversion on it
- one after another until one fails or the conversion is completed.
- Returns NULL on success, or a pointer to a string with the reason why the
- conversion failed. */
-
-static const char *
-process_switch (gswitch *swtch)
+const char *
+switch_conversion::expand (gswitch *swtch)
{
- struct switch_conv_info info;
-
/* Group case labels so that we get the right results from the heuristics
that decide on the code generation approach for this switch. */
group_case_labels_stmt (swtch);
/* If this switch is now a degenerate case with only a default label,
- there is nothing left for us to do. */
+ there is nothing left for us to do. */
if (gimple_switch_num_labels (swtch) < 2)
return "switch is a degenerate case";
- collect_switch_conv_info (swtch, &info);
+ collect (swtch);
/* No error markers should reach here (they should be filtered out
during gimplification). */
- gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node);
+ gcc_checking_assert (TREE_TYPE (m_index_expr) != error_mark_node);
/* A switch on a constant should have been optimized in tree-cfg-cleanup. */
- gcc_checking_assert (! TREE_CONSTANT (info.index_expr));
-
- if (info.uniq <= MAX_CASE_BIT_TESTS)
- {
- if (expand_switch_using_bit_tests_p (info.range_size,
- info.uniq, info.count,
- optimize_bb_for_speed_p
- (gimple_bb (swtch))))
- {
- if (dump_file)
- fputs (" expanding as bit test is preferable\n", dump_file);
- emit_case_bit_tests (swtch, info.index_expr, info.range_min,
- info.range_size, info.range_max);
- loops_state_set (LOOPS_NEED_FIXUP);
- return NULL;
- }
-
- if (info.uniq <= 2)
- /* This will be expanded as a decision tree in stmt.c:expand_case. */
- return " expanding as jumps is preferable";
- }
+ gcc_checking_assert (!TREE_CONSTANT (m_index_expr));
/* If there is no common successor, we cannot do the transformation. */
- if (! info.final_bb)
+ if (!m_final_bb)
return "no common successor to all case label target blocks found";
/* Check the case label values are within reasonable range: */
- if (!check_range (&info))
+ if (!check_range ())
{
- gcc_assert (info.reason);
- return info.reason;
+ gcc_assert (m_reason);
+ return m_reason;
}
/* For all the cases, see whether they are empty, the assignments they
represent constant and so on... */
- if (! check_all_empty_except_final (&info))
+ if (!check_all_empty_except_final ())
{
- gcc_assert (info.reason);
- return info.reason;
+ gcc_assert (m_reason);
+ return m_reason;
}
- if (!check_final_bb (swtch, &info))
+ if (!check_final_bb ())
{
- gcc_assert (info.reason);
- return info.reason;
+ gcc_assert (m_reason);
+ return m_reason;
}
/* At this point all checks have passed and we can proceed with the
transformation. */
- create_temp_arrays (&info);
- gather_default_values (info.default_case_nonstandard
+ create_temp_arrays ();
+ gather_default_values (m_default_case_nonstandard
? gimple_switch_label (swtch, 1)
- : gimple_switch_default_label (swtch), &info);
- build_constructors (swtch, &info);
+ : gimple_switch_default_label (swtch));
+ build_constructors ();
- build_arrays (swtch, &info); /* Build the static arrays and assignments. */
- gen_inbound_check (swtch, &info); /* Build the bounds check. */
+ build_arrays (); /* Build the static arrays and assignments. */
+ gen_inbound_check (); /* Build the bounds check. */
- /* Cleanup: */
- free_temp_arrays (&info);
return NULL;
}
+switch_conversion::~switch_conversion ()
+{
+ XDELETEVEC (m_constructors);
+ XDELETEVEC (m_default_values);
+}
+
/* The main function of the pass scans statements for switches and invokes
process_switch on them. */
@@ -1628,8 +955,9 @@ pass_convert_switch::execute (function *fun)
putc ('\n', dump_file);
}
- failure_reason = process_switch (as_a <gswitch *> (stmt));
- if (! failure_reason)
+ switch_conversion sconv;
+ failure_reason = sconv.expand (as_a <gswitch *> (stmt));
+ if (!failure_reason)
{
if (dump_file)
{
@@ -1637,9 +965,10 @@ pass_convert_switch::execute (function *fun)
fputs ("--------------------------------\n", dump_file);
}
- /* Make no effort to update the post-dominator tree. It is actually not
- that hard for the transformations we have performed, but it is not
- supported by iterate_fix_dominators. */
+ /* Make no effort to update the post-dominator tree.
+ It is actually not that hard for the transformations
+ we have performed, but it is not supported
+ by iterate_fix_dominators. */
free_dominance_info (CDI_POST_DOMINATORS);
}
else
@@ -1659,70 +988,453 @@ pass_convert_switch::execute (function *fun)
} // anon namespace
-gimple_opt_pass *
-make_pass_convert_switch (gcc::context *ctxt)
+group_cluster::~group_cluster ()
{
- return new pass_convert_switch (ctxt);
+ for (unsigned i = 0; i < m_cases.length (); i++)
+ delete m_cases[i];
+
+ m_cases.release ();
}
-struct case_node
+jump_table_cluster::jump_table_cluster (vec<cluster *> &clusters,
+ unsigned start, unsigned end)
{
- case_node *left; /* Left son in binary tree. */
- case_node *right; /* Right son in binary tree;
- also node chain. */
- case_node *parent; /* Parent of node in binary tree. */
- tree low; /* Lowest index value for this label. */
- tree high; /* Highest index value for this label. */
- basic_block case_bb; /* Label to jump to when node matches. */
- tree case_label; /* Label to jump to when node matches. */
- profile_probability prob; /* Probability of taking this case. */
- profile_probability subtree_prob; /* Probability of reaching subtree
- rooted at this node. */
-};
+ gcc_checking_assert (end - start + 1 >= 1);
+ m_prob = profile_probability::never ();
+ m_cases.create (end - start + 1);
+ for (unsigned i = start; i <= end; i++)
+ {
+ m_cases.quick_push (static_cast<simple_cluster *> (clusters[i]));
+ m_prob += clusters[i]->m_prob;
+ }
+ m_subtree_prob = m_prob;
+}
+
+void
+jump_table_cluster::emit (tree index_expr, tree,
+ tree default_label_expr, basic_block default_bb)
+{
+ /* For jump table we just emit a new gswitch statement that will
+ be latter lowered to jump table. */
+ auto_vec <tree> labels;
+ labels.create (m_cases.length ());
+
+ make_edge (m_case_bb, default_bb, 0);
+ for (unsigned i = 0; i < m_cases.length (); i++)
+ {
+ labels.quick_push (unshare_expr (m_cases[i]->m_case_label_expr));
+ make_edge (m_case_bb, m_cases[i]->m_case_bb, 0);
+ }
+
+ gswitch *s = gimple_build_switch (index_expr,
+ unshare_expr (default_label_expr), labels);
+ gimple_stmt_iterator gsi = gsi_start_bb (m_case_bb);
+ gsi_insert_after (&gsi, s, GSI_NEW_STMT);
+}
+
+vec<cluster *>
+jump_table_cluster::find_jump_tables (vec<cluster *> &clusters)
+{
+ unsigned l = clusters.length ();
+ auto_vec<min_cluster_item> min;
+ min.reserve (l + 1);
+
+ min.quick_push (min_cluster_item (0, 0, 0));
+
+ for (unsigned i = 1; i <= l; i++)
+ {
+ /* Set minimal # of clusters with i-th item to infinite. */
+ min.quick_push (min_cluster_item (INT_MAX, INT_MAX, INT_MAX));
+
+ for (unsigned j = 0; j < i; j++)
+ {
+ unsigned HOST_WIDE_INT s = min[j].m_non_jt_cases;
+ if (i - j < case_values_threshold ())
+ s += i - j;
+
+ /* Prefer clusters with smaller number of numbers covered. */
+ if ((min[j].m_count + 1 < min[i].m_count
+ || (min[j].m_count + 1 == min[i].m_count
+ && s < min[i].m_non_jt_cases))
+ && can_be_handled (clusters, j, i - 1))
+ min[i] = min_cluster_item (min[j].m_count + 1, j, s);
+ }
+ }
+
+ /* No result. */
+ if (min[l].m_count == INT_MAX)
+ return clusters.copy ();
+
+ vec<cluster *> output;
+ output.create (4);
+
+ /* Find and build the clusters. */
+ for (int end = l;;)
+ {
+ int start = min[end].m_start;
+
+ /* Do not allow clusters with small number of cases. */
+ if (is_beneficial (clusters, start, end - 1))
+ output.safe_push (new jump_table_cluster (clusters, start, end - 1));
+ else
+ for (int i = end - 1; i >= start; i--)
+ output.safe_push (clusters[i]);
+
+ end = start;
+
+ if (start <= 0)
+ break;
+ }
+
+ output.reverse ();
+ return output;
+}
+
+bool
+jump_table_cluster::can_be_handled (const vec<cluster *> &clusters,
+ unsigned start, unsigned end)
+{
+ /* If the switch is relatively small such that the cost of one
+ indirect jump on the target are higher than the cost of a
+ decision tree, go with the decision tree.
+
+ If range of values is much bigger than number of values,
+ or if it is too large to represent in a HOST_WIDE_INT,
+ make a sequence of conditional branches instead of a dispatch.
+
+ The definition of "much bigger" depends on whether we are
+ optimizing for size or for speed. If the former, the maximum
+ ratio range/count = 3, because this was found to be the optimal
+ ratio for size on i686-pc-linux-gnu, see PR11823. The ratio
+ 10 is much older, and was probably selected after an extensive
+ benchmarking investigation on numerous platforms. Or maybe it
+ just made sense to someone at some point in the history of GCC,
+ who knows... */
+ if (!flag_jump_tables)
+ return false;
+
+ unsigned HOST_WIDE_INT max_ratio = optimize_insn_for_size_p () ? 3 : 10;
+
+ unsigned HOST_WIDE_INT range = get_range (clusters[start]->get_low (),
+ clusters[end]->get_high ());
+
+ unsigned HOST_WIDE_INT value_count = 0;
+ for (unsigned i = start; i <= end; i++)
+ value_count += get_range (clusters[i]->get_low (),
+ clusters[i]->get_high ());
+
+ return range <= max_ratio * value_count;
+}
+
+bool
+jump_table_cluster::is_beneficial (const vec<cluster *> &,
+ unsigned start, unsigned end)
+{
+ return end - start + 1 >= case_values_threshold ();
+}
+
+bit_test_cluster::bit_test_cluster (vec<cluster *> &clusters,
+ unsigned start, unsigned end)
+{
+ gcc_checking_assert (end - start + 1 >= 1);
+ m_prob = profile_probability::never ();
+ m_cases.create (end - start + 1);
+ for (unsigned i = start; i <= end; i++)
+ {
+ m_prob += clusters[i]->m_prob;
+ m_cases.safe_push (static_cast<simple_cluster *> (clusters[i]));
+ }
+
+ m_subtree_prob = m_prob;
+}
+
+vec<cluster *>
+bit_test_cluster::find_bit_tests (vec<cluster *> &clusters)
+{
+ vec<cluster *> output;
+ output.create (4);
+
+ unsigned l = clusters.length ();
+ auto_vec<min_cluster_item> min;
+ min.reserve (l + 1);
+
+ min.quick_push (min_cluster_item (0, 0, 0));
+
+ for (unsigned i = 1; i <= l; i++)
+ {
+ /* Set minimal # of clusters with i-th item to infinite. */
+ min.quick_push (min_cluster_item (INT_MAX, INT_MAX, INT_MAX));
+
+ for (unsigned j = 0; j < i; j++)
+ {
+ if (min[j].m_count + 1 < min[i].m_count
+ && can_be_handled (clusters, j, i - 1))
+ min[i] = min_cluster_item (min[j].m_count + 1, j, INT_MAX);
+ }
+ }
+
+ /* No result. */
+ if (min[l].m_count == INT_MAX)
+ return clusters.copy ();
+
+ /* Find and build the clusters. */
+ for (int end = l;;)
+ {
+ int start = min[end].m_start;
+
+ if (is_beneficial (clusters, start, end - 1))
+ output.safe_push (new bit_test_cluster (clusters, start, end - 1));
+ else
+ for (int i = end - 1; i >= start; i--)
+ output.safe_push (clusters[i]);
+
+ end = start;
+
+ if (start <= 0)
+ break;
+ }
+
+ output.reverse ();
+ return output;
+}
+
+bool
+bit_test_cluster::can_be_handled (const vec<cluster *> &clusters,
+ unsigned start, unsigned end)
+{
+ HOST_WIDE_INT range = get_range (clusters[start]->get_low (),
+ clusters[end]->get_high ());
+
+ if (range >= GET_MODE_BITSIZE (word_mode))
+ return false;
+
+ auto_bitmap dest_bbs;
+
+ for (unsigned i = start; i <= end; i++)
+ {
+ simple_cluster *sc = static_cast<simple_cluster *> (clusters[i]);
+ bitmap_set_bit (dest_bbs, sc->m_case_bb->index);
+ }
+
+ return bitmap_count_bits (dest_bbs) <= 3;
+}
+
+bool
+bit_test_cluster::is_beneficial (const vec<cluster *> &clusters,
+ unsigned start, unsigned end)
+{
+ auto_bitmap dest_bbs;
+
+ for (unsigned i = start; i <= end; i++)
+ {
+ simple_cluster *sc = static_cast<simple_cluster *> (clusters[i]);
+ bitmap_set_bit (dest_bbs, sc->m_case_bb->index);
+ }
+
+ unsigned HOST_WIDE_INT uniq = bitmap_count_bits (dest_bbs);
+ unsigned HOST_WIDE_INT count = end - start + 1;
+
+ return (((uniq == 1 && count >= 3)
+ || (uniq == 2 && count >= 5)
+ || (uniq == 3 && count >= 6)));
+}
-typedef case_node *case_node_ptr;
+int
+case_bit_test::cmp (const void *p1, const void *p2)
+{
+ const struct case_bit_test *const d1 = (const struct case_bit_test *) p1;
+ const struct case_bit_test *const d2 = (const struct case_bit_test *) p2;
-static basic_block emit_case_nodes (basic_block, tree, case_node_ptr,
- basic_block, tree, profile_probability,
- tree, hash_map<tree, tree> *);
+ if (d2->bits != d1->bits)
+ return d2->bits - d1->bits;
-/* Return the smallest number of different values for which it is best to use a
- jump-table instead of a tree of conditional branches. */
+ /* Stabilize the sort. */
+ return (LABEL_DECL_UID (CASE_LABEL (d2->label))
+ - LABEL_DECL_UID (CASE_LABEL (d1->label)));
+}
-static unsigned int
-case_values_threshold (void)
+void
+bit_test_cluster::emit (tree index_expr, tree index_type,
+ tree, basic_block default_bb)
{
- unsigned int threshold = PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD);
+ struct case_bit_test test[m_max_case_bit_tests] = { {} };
+ unsigned int i, j, k;
+ unsigned int count;
+
+ tree unsigned_index_type = unsigned_type_for (index_type);
+
+ gimple_stmt_iterator gsi;
+ gassign *shift_stmt;
+
+ tree idx, tmp, csui;
+ tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1);
+ tree word_mode_zero = fold_convert (word_type_node, integer_zero_node);
+ tree word_mode_one = fold_convert (word_type_node, integer_one_node);
+ int prec = TYPE_PRECISION (word_type_node);
+ wide_int wone = wi::one (prec);
- if (threshold == 0)
- threshold = targetm.case_values_threshold ();
+ tree minval = get_low ();
+ tree maxval = get_high ();
+ tree range = int_const_binop (MINUS_EXPR, maxval, minval);
+
+ /* Go through all case labels, and collect the case labels, profile
+ counts, and other information we need to build the branch tests. */
+ count = 0;
+ for (i = 0; i < m_cases.length (); i++)
+ {
+ unsigned int lo, hi;
+ simple_cluster *n = static_cast<simple_cluster *> (m_cases[i]);
+ for (k = 0; k < count; k++)
+ if (n->m_case_bb == test[k].target_bb)
+ break;
- return threshold;
+ if (k == count)
+ {
+ gcc_checking_assert (count < m_max_case_bit_tests);
+ test[k].mask = wi::zero (prec);
+ test[k].target_bb = n->m_case_bb;
+ test[k].label = n->m_case_label_expr;
+ test[k].bits = 1;
+ count++;
+ }
+ else
+ test[k].bits++;
+
+ lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, n->get_low (), minval));
+ if (n->get_high () == NULL_TREE)
+ hi = lo;
+ else
+ hi = tree_to_uhwi (int_const_binop (MINUS_EXPR, n->get_high (),
+ minval));
+
+ for (j = lo; j <= hi; j++)
+ test[k].mask |= wi::lshift (wone, j);
+ }
+
+ qsort (test, count, sizeof (*test), case_bit_test::cmp);
+
+ /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of
+ the minval subtractions, but it might make the mask constants more
+ expensive. So, compare the costs. */
+ if (compare_tree_int (minval, 0) > 0
+ && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
+ {
+ int cost_diff;
+ HOST_WIDE_INT m = tree_to_uhwi (minval);
+ rtx reg = gen_raw_REG (word_mode, 10000);
+ bool speed_p = optimize_insn_for_speed_p ();
+ cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg,
+ GEN_INT (-m)), speed_p);
+ for (i = 0; i < count; i++)
+ {
+ rtx r = immed_wide_int_const (test[i].mask, word_mode);
+ cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r),
+ word_mode, speed_p);
+ r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode);
+ cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r),
+ word_mode, speed_p);
+ }
+ if (cost_diff > 0)
+ {
+ for (i = 0; i < count; i++)
+ test[i].mask = wi::lshift (test[i].mask, m);
+ minval = build_zero_cst (TREE_TYPE (minval));
+ range = maxval;
+ }
+ }
+
+ /* Now build the test-and-branch code. */
+
+ gsi = gsi_last_bb (m_case_bb);
+
+ /* idx = (unsigned)x - minval. */
+ idx = fold_convert (unsigned_index_type, index_expr);
+ idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx,
+ fold_convert (unsigned_index_type, minval));
+ idx = force_gimple_operand_gsi (&gsi, idx,
+ /*simple=*/true, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+
+ /* if (idx > range) goto default */
+ range = force_gimple_operand_gsi (&gsi,
+ fold_convert (unsigned_index_type, range),
+ /*simple=*/true, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+ tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range);
+ basic_block new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_bb);
+ gsi = gsi_last_bb (new_bb);
+
+ /* csui = (1 << (word_mode) idx) */
+ csui = make_ssa_name (word_type_node);
+ tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one,
+ fold_convert (word_type_node, idx));
+ tmp = force_gimple_operand_gsi (&gsi, tmp,
+ /*simple=*/false, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+ shift_stmt = gimple_build_assign (csui, tmp);
+ gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT);
+ update_stmt (shift_stmt);
+
+ /* for each unique set of cases:
+ if (const & csui) goto target */
+ for (k = 0; k < count; k++)
+ {
+ tmp = wide_int_to_tree (word_type_node, test[k].mask);
+ tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp);
+ tmp = force_gimple_operand_gsi (&gsi, tmp,
+ /*simple=*/true, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+ tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero);
+ new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_bb);
+ gsi = gsi_last_bb (new_bb);
+ }
+
+ /* We should have removed all edges now. */
+ gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0);
+
+ /* If nothing matched, go to the default label. */
+ make_edge (gsi_bb (gsi), default_bb, EDGE_FALLTHRU);
}
-/* Reset the aux field of all outgoing edges of basic block BB. */
+basic_block
+bit_test_cluster::hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip,
+ tree cond, basic_block case_bb)
+{
+ tree tmp;
+ gcond *cond_stmt;
+ edge e_false;
+ basic_block new_bb, split_bb = gsi_bb (*gsip);
+
+ edge e_true = make_edge (split_bb, case_bb, EDGE_TRUE_VALUE);
+ gcc_assert (e_true->src == split_bb);
+
+ tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL,
+ /*before=*/true, GSI_SAME_STMT);
+ cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE);
+ gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT);
+
+ e_false = split_block (split_bb, cond_stmt);
+ new_bb = e_false->dest;
+ redirect_edge_pred (e_true, split_bb);
+
+ e_false->flags &= ~EDGE_FALLTHRU;
+ e_false->flags |= EDGE_FALSE_VALUE;
+ e_false->probability = e_true->probability.invert ();
+ e_false->count = split_bb->count - e_true->count;
+ new_bb->count = e_false->count;
-static inline void
-reset_out_edges_aux (basic_block bb)
-{
- edge e;
- edge_iterator ei;
- FOR_EACH_EDGE (e, ei, bb->succs)
- e->aux = (void *) 0;
+ return new_bb;
}
-/* Compute the number of case labels that correspond to each outgoing edge of
- STMT. Record this information in the aux field of the edge. */
-
-static inline void
-compute_cases_per_edge (gswitch *stmt)
+void
+switch_decision_tree::compute_cases_per_edge ()
{
- basic_block bb = gimple_bb (stmt);
- reset_out_edges_aux (bb);
- int ncases = gimple_switch_num_labels (stmt);
+ basic_block bb = gimple_bb (m_switch);
+ reset_out_edges_aux ();
+ int ncases = gimple_switch_num_labels (m_switch);
for (int i = ncases - 1; i >= 1; --i)
{
- tree elt = gimple_switch_label (stmt, i);
+ tree elt = gimple_switch_label (m_switch, i);
tree lab = CASE_LABEL (elt);
basic_block case_bb = label_to_block_fn (cfun, lab);
edge case_edge = find_edge (bb, case_bb);
@@ -1730,250 +1442,126 @@ compute_cases_per_edge (gswitch *stmt)
}
}
-/* Do the insertion of a case label into case_list. The labels are
- fed to us in descending order from the sorted vector of case labels used
- in the tree part of the middle end. So the list we construct is
- sorted in ascending order.
-
- LABEL is the case label to be inserted. LOW and HIGH are the bounds
- against which the index is compared to jump to LABEL and PROB is the
- estimated probability LABEL is reached from the switch statement. */
-
-static case_node *
-add_case_node (case_node *head, tree low, tree high, basic_block case_bb,
- tree case_label, profile_probability prob,
- object_allocator<case_node> &case_node_pool)
+bool
+switch_decision_tree::analyze_switch_statement ()
{
- case_node *r;
-
- gcc_checking_assert (low);
- gcc_checking_assert (high && (TREE_TYPE (low) == TREE_TYPE (high)));
-
- /* Add this label to the chain. */
- r = case_node_pool.allocate ();
- r->low = low;
- r->high = high;
- r->case_bb = case_bb;
- r->case_label = case_label;
- r->parent = r->left = NULL;
- r->prob = prob;
- r->subtree_prob = prob;
- r->right = head;
- return r;
-}
-
-/* Dump ROOT, a list or tree of case nodes, to file. */
+ unsigned l = gimple_switch_num_labels (m_switch);
+ basic_block bb = gimple_bb (m_switch);
+ auto_vec<cluster *> clusters;
+ clusters.create (l - 1);
-static void
-dump_case_nodes (FILE *f, case_node *root, int indent_step, int indent_level)
-{
- if (root == 0)
- return;
- indent_level++;
+ tree default_label = CASE_LABEL (gimple_switch_default_label (m_switch));
+ basic_block default_bb = label_to_block_fn (cfun, default_label);
+ m_case_bbs.reserve (l);
+ m_case_bbs.quick_push (default_bb);
- dump_case_nodes (f, root->left, indent_step, indent_level);
+ compute_cases_per_edge ();
- fputs (";; ", f);
- fprintf (f, "%*s", indent_step * indent_level, "");
- print_dec (root->low, f, TYPE_SIGN (TREE_TYPE (root->low)));
- if (!tree_int_cst_equal (root->low, root->high))
+ for (unsigned i = 1; i < l; i++)
{
- fprintf (f, " ... ");
- print_dec (root->high, f, TYPE_SIGN (TREE_TYPE (root->high)));
- }
- fputs ("\n", f);
+ tree elt = gimple_switch_label (m_switch, i);
+ tree lab = CASE_LABEL (elt);
+ basic_block case_bb = label_to_block_fn (cfun, lab);
+ edge case_edge = find_edge (bb, case_bb);
+ tree low = CASE_LOW (elt);
+ tree high = CASE_HIGH (elt);
+ if (high == NULL_TREE)
+ high = low;
- dump_case_nodes (f, root->right, indent_step, indent_level);
-}
+ profile_probability p
+ = case_edge->probability.apply_scale (1, (intptr_t) (case_edge->aux));
+ clusters.quick_push (new simple_cluster (low, high, elt, case_bb, p));
+ m_case_bbs.quick_push (case_bb);
+ }
-/* Take an ordered list of case nodes
- and transform them into a near optimal binary tree,
- on the assumption that any target code selection value is as
- likely as any other.
+ reset_out_edges_aux ();
- The transformation is performed by splitting the ordered
- list into two equal sections plus a pivot. The parts are
- then attached to the pivot as left and right branches. Each
- branch is then transformed recursively. */
+ /* Find jump table clusters. */
+ vec<cluster *> output = jump_table_cluster::find_jump_tables (clusters);
-static void
-balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
-{
- case_node_ptr np;
+ /* Find jump table clusters. */
+ vec<cluster *> output2;
+ auto_vec<cluster *> tmp;
+ output2.create (1);
+ tmp.create (1);
- np = *head;
- if (np)
+ for (unsigned i = 0; i < output.length (); i++)
{
- int i = 0;
- int ranges = 0;
- case_node_ptr *npp;
- case_node_ptr left;
-
- /* Count the number of entries on branch. Also count the ranges. */
-
- while (np)
- {
- if (!tree_int_cst_equal (np->low, np->high))
- ranges++;
-
- i++;
- np = np->right;
- }
-
- if (i > 2)
+ cluster *c = output[i];
+ if (c->get_type () != SIMPLE_CASE)
{
- /* Split this list if it is long enough for that to help. */
- npp = head;
- left = *npp;
-
- /* If there are just three nodes, split at the middle one. */
- if (i == 3)
- npp = &(*npp)->right;
- else
+ if (!tmp.is_empty ())
{
- /* Find the place in the list that bisects the list's total cost,
- where ranges count as 2.
- Here I gets half the total cost. */
- i = (i + ranges + 1) / 2;
- while (1)
- {
- /* Skip nodes while their cost does not reach that amount. */
- if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
- i--;
- i--;
- if (i <= 0)
- break;
- npp = &(*npp)->right;
- }
+ vec<cluster *> n = bit_test_cluster::find_bit_tests (tmp);
+ output2.safe_splice (n);
+ n.release ();
+ tmp.truncate (0);
}
- *head = np = *npp;
- *npp = 0;
- np->parent = parent;
- np->left = left;
-
- /* Optimize each of the two split parts. */
- balance_case_nodes (&np->left, np);
- balance_case_nodes (&np->right, np);
- np->subtree_prob = np->prob;
- np->subtree_prob += np->left->subtree_prob;
- np->subtree_prob += np->right->subtree_prob;
+ output2.safe_push (c);
}
else
- {
- /* Else leave this branch as one level,
- but fill in `parent' fields. */
- np = *head;
- np->parent = parent;
- np->subtree_prob = np->prob;
- for (; np->right; np = np->right)
- {
- np->right->parent = np;
- (*head)->subtree_prob += np->right->subtree_prob;
- }
- }
+ tmp.safe_push (c);
}
-}
-
-/* Return true if a switch should be expanded as a decision tree.
- RANGE is the difference between highest and lowest case.
- UNIQ is number of unique case node targets, not counting the default case.
- COUNT is the number of comparisons needed, not counting the default case. */
-
-static bool
-expand_switch_as_decision_tree_p (tree range,
- unsigned int uniq ATTRIBUTE_UNUSED,
- unsigned int count)
-{
- int max_ratio;
- /* If neither casesi or tablejump is available, or flag_jump_tables
- over-ruled us, we really have no choice. */
- if (!targetm.have_casesi () && !targetm.have_tablejump ())
- return true;
- if (!flag_jump_tables)
- return true;
-#ifndef ASM_OUTPUT_ADDR_DIFF_ELT
- if (flag_pic)
- return true;
-#endif
+ /* We still can have a temporary vector to test. */
+ if (!tmp.is_empty ())
+ {
+ vec<cluster *> n = bit_test_cluster::find_bit_tests (tmp);
+ output2.safe_splice (n);
+ n.release ();
+ }
- /* If the switch is relatively small such that the cost of one
- indirect jump on the target are higher than the cost of a
- decision tree, go with the decision tree.
+ if (dump_file)
+ {
+ fprintf (dump_file, ";; GIMPLE switch case clusters: ");
+ for (unsigned i = 0; i < output2.length (); i++)
+ output2[i]->dump (dump_file);
+ fprintf (dump_file, "\n");
+ }
- If range of values is much bigger than number of values,
- or if it is too large to represent in a HOST_WIDE_INT,
- make a sequence of conditional branches instead of a dispatch.
+ output.release ();
- The definition of "much bigger" depends on whether we are
- optimizing for size or for speed. If the former, the maximum
- ratio range/count = 3, because this was found to be the optimal
- ratio for size on i686-pc-linux-gnu, see PR11823. The ratio
- 10 is much older, and was probably selected after an extensive
- benchmarking investigation on numerous platforms. Or maybe it
- just made sense to someone at some point in the history of GCC,
- who knows... */
- max_ratio = optimize_insn_for_size_p () ? 3 : 10;
- if (count < case_values_threshold () || !tree_fits_uhwi_p (range)
- || compare_tree_int (range, max_ratio * count) > 0)
- return true;
+ bool expanded = try_switch_expansion (output2);
- return false;
-}
+ for (unsigned i = 0; i < output2.length (); i++)
+ delete output2[i];
-static void
-fix_phi_operands_for_edge (edge e, hash_map<tree, tree> *phi_mapping)
-{
- basic_block bb = e->dest;
- gphi_iterator gsi;
- for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gphi *phi = gsi.phi ();
+ output2.release ();
- tree *definition = phi_mapping->get (gimple_phi_result (phi));
- if (definition)
- add_phi_arg (phi, *definition, e, UNKNOWN_LOCATION);
- }
+ return expanded;
}
-
-/* Add an unconditional jump to CASE_BB that happens in basic block BB. */
-
-static void
-emit_jump (basic_block bb, basic_block case_bb,
- hash_map<tree, tree> *phi_mapping)
+bool
+switch_decision_tree::try_switch_expansion (vec<cluster *> &clusters)
{
- edge e = single_succ_edge (bb);
- redirect_edge_succ (e, case_bb);
- fix_phi_operands_for_edge (e, phi_mapping);
-}
+ tree index_expr = gimple_switch_index (m_switch);
+ tree index_type = TREE_TYPE (index_expr);
+ basic_block bb = gimple_bb (m_switch);
-/* Generate a decision tree, switching on INDEX_EXPR and jumping to
- one of the labels in CASE_LIST or to the DEFAULT_LABEL.
- DEFAULT_PROB is the estimated probability that it jumps to
- DEFAULT_LABEL.
+ if (gimple_switch_num_labels (m_switch) == 1)
+ return false;
- We generate a binary decision tree to select the appropriate target
- code. */
+ /* Find the default case target label. */
+ tree default_label_expr = CASE_LABEL (gimple_switch_default_label (m_switch));
+ m_default_bb = label_to_block_fn (cfun, default_label_expr);
+ edge default_edge = find_edge (bb, m_default_bb);
-static void
-emit_case_decision_tree (gswitch *s, tree index_expr, tree index_type,
- case_node_ptr case_list, basic_block default_bb,
- tree default_label, profile_probability default_prob,
- hash_map<tree, tree> *phi_mapping)
-{
- balance_case_nodes (&case_list, NULL);
+ /* Do the insertion of a case label into m_case_list. The labels are
+ fed to us in descending order from the sorted vector of case labels used
+ in the tree part of the middle end. So the list we construct is
+ sorted in ascending order. */
- if (dump_file)
- dump_function_to_file (current_function_decl, dump_file, dump_flags);
- if (dump_file && (dump_flags & TDF_DETAILS))
+ for (int i = clusters.length () - 1; i >= 0; i--)
{
- int indent_step = ceil_log2 (TYPE_PRECISION (index_type)) + 2;
- fprintf (dump_file, ";; Expanding GIMPLE switch as decision tree:\n");
- dump_case_nodes (dump_file, case_list, indent_step, 0);
+ case_tree_node *r = m_case_list;
+ m_case_list = m_case_node_pool.allocate ();
+ m_case_list->m_right = r;
+ m_case_list->m_c = clusters[i];
}
- basic_block bb = gimple_bb (s);
+ record_phi_operand_mapping ();
+
+ /* Split basic block that contains the gswitch statement. */
gimple_stmt_iterator gsi = gsi_last_bb (bb);
edge e;
if (gsi_end_p (gsi))
@@ -1985,27 +1573,37 @@ emit_case_decision_tree (gswitch *s, tree index_expr, tree index_type,
}
bb = split_edge (e);
- bb = emit_case_nodes (bb, index_expr, case_list, default_bb, default_label,
- default_prob, index_type, phi_mapping);
+ /* Create new basic blocks for non-case clusters where specific expansion
+ needs to happen. */
+ for (unsigned i = 0; i < clusters.length (); i++)
+ if (clusters[i]->get_type () != SIMPLE_CASE)
+ {
+ clusters[i]->m_case_bb = create_empty_bb (bb);
+ clusters[i]->m_case_bb->loop_father = bb->loop_father;
+ }
+
+ emit (bb, index_expr, default_edge->probability, index_type);
- if (bb)
- emit_jump (bb, default_bb, phi_mapping);
+ /* Emit cluster-specific switch handling. */
+ for (unsigned i = 0; i < clusters.length (); i++)
+ if (clusters[i]->get_type () != SIMPLE_CASE)
+ clusters[i]->emit (index_expr, index_type,
+ gimple_switch_default_label (m_switch), m_default_bb);
- /* Remove all edges and do just an edge that will reach default_bb. */
- gsi = gsi_last_bb (gimple_bb (s));
- gsi_remove (&gsi, true);
+ fix_phi_operands_for_edges ();
+
+ return true;
}
-static void
-record_phi_operand_mapping (const vec<basic_block> bbs, basic_block switch_bb,
- hash_map <tree, tree> *map)
+void
+switch_decision_tree::record_phi_operand_mapping ()
{
+ basic_block switch_bb = gimple_bb (m_switch);
/* Record all PHI nodes that have to be fixed after conversion. */
- for (unsigned i = 0; i < bbs.length (); i++)
+ for (unsigned i = 0; i < m_case_bbs.length (); i++)
{
- basic_block bb = bbs[i];
-
gphi_iterator gsi;
+ basic_block bb = m_case_bbs[i];
for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gphi *phi = gsi.phi ();
@@ -2017,7 +1615,7 @@ record_phi_operand_mapping (const vec<basic_block> bbs, basic_block switch_bb,
{
tree def = gimple_phi_arg_def (phi, i);
tree result = gimple_phi_result (phi);
- map->put (result, def);
+ m_phi_mapping.put (result, def);
break;
}
}
@@ -2025,133 +1623,174 @@ record_phi_operand_mapping (const vec<basic_block> bbs, basic_block switch_bb,
}
}
-/* Attempt to expand gimple switch STMT to a decision tree. */
-
-static bool
-try_switch_expansion (gswitch *stmt)
+void
+switch_decision_tree::fix_phi_operands_for_edges ()
{
- tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
- basic_block default_bb;
- unsigned int count, uniq;
- int i;
- int ncases = gimple_switch_num_labels (stmt);
- tree index_expr = gimple_switch_index (stmt);
- tree index_type = TREE_TYPE (index_expr);
- tree elt;
- basic_block bb = gimple_bb (stmt);
+ gphi_iterator gsi;
- hash_map<tree, tree> phi_mapping;
- auto_vec<basic_block> case_bbs;
+ for (unsigned i = 0; i < m_case_bbs.length (); i++)
+ {
+ basic_block bb = m_case_bbs[i];
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gphi *phi = gsi.phi ();
+ for (unsigned j = 0; j < gimple_phi_num_args (phi); j++)
+ {
+ tree def = gimple_phi_arg_def (phi, j);
+ if (def == NULL_TREE)
+ {
+ edge e = gimple_phi_arg_edge (phi, j);
+ tree *definition
+ = m_phi_mapping.get (gimple_phi_result (phi));
+ gcc_assert (definition);
+ add_phi_arg (phi, *definition, e, UNKNOWN_LOCATION);
+ }
+ }
+ }
+ }
+}
- /* A list of case labels; it is first built as a list and it may then
- be rearranged into a nearly balanced binary tree. */
- case_node *case_list = 0;
+void
+switch_decision_tree::emit (basic_block bb, tree index_expr,
+ profile_probability default_prob, tree index_type)
+{
+ balance_case_nodes (&m_case_list, NULL);
- /* A pool for case nodes. */
- object_allocator<case_node> case_node_pool ("struct case_node pool");
+ if (dump_file)
+ dump_function_to_file (current_function_decl, dump_file, dump_flags);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ int indent_step = ceil_log2 (TYPE_PRECISION (index_type)) + 2;
+ fprintf (dump_file, ";; Expanding GIMPLE switch as decision tree:\n");
+ gcc_assert (m_case_list != NULL);
+ dump_case_nodes (dump_file, m_case_list, indent_step, 0);
+ }
- /* cleanup_tree_cfg removes all SWITCH_EXPR with their index
- expressions being INTEGER_CST. */
- gcc_assert (TREE_CODE (index_expr) != INTEGER_CST);
+ bb = emit_case_nodes (bb, index_expr, m_case_list, default_prob, index_type);
- if (ncases == 1)
- return false;
+ if (bb)
+ emit_jump (bb, m_default_bb);
- /* Find the default case target label. */
- tree default_label = CASE_LABEL (gimple_switch_default_label (stmt));
- default_bb = label_to_block_fn (cfun, default_label);
- edge default_edge = find_edge (bb, default_bb);
- profile_probability default_prob = default_edge->probability;
- case_bbs.safe_push (default_bb);
-
- /* Get upper and lower bounds of case values. */
- elt = gimple_switch_label (stmt, 1);
- minval = fold_convert (index_type, CASE_LOW (elt));
- elt = gimple_switch_label (stmt, ncases - 1);
- if (CASE_HIGH (elt))
- maxval = fold_convert (index_type, CASE_HIGH (elt));
- else
- maxval = fold_convert (index_type, CASE_LOW (elt));
+ /* Remove all edges and do just an edge that will reach default_bb. */
+ bb = gimple_bb (m_switch);
+ gimple_stmt_iterator gsi = gsi_last_bb (bb);
+ gsi_remove (&gsi, true);
- /* Compute span of values. */
- range = fold_build2 (MINUS_EXPR, index_type, maxval, minval);
+ delete_basic_block (bb);
+}
- /* Listify the labels queue and gather some numbers to decide
- how to expand this switch. */
- uniq = 0;
- count = 0;
- hash_set<tree> seen_labels;
- compute_cases_per_edge (stmt);
+void
+switch_decision_tree::balance_case_nodes (case_tree_node **head,
+ case_tree_node *parent)
+{
+ case_tree_node *np;
- for (i = ncases - 1; i >= 1; --i)
+ np = *head;
+ if (np)
{
- elt = gimple_switch_label (stmt, i);
- tree low = CASE_LOW (elt);
- gcc_assert (low);
- tree high = CASE_HIGH (elt);
- gcc_assert (!high || tree_int_cst_lt (low, high));
- tree lab = CASE_LABEL (elt);
+ int i = 0;
+ int ranges = 0;
+ case_tree_node **npp;
+ case_tree_node *left;
- /* Count the elements.
- A range counts double, since it requires two compares. */
- count++;
- if (high)
- count++;
-
- /* If we have not seen this label yet, then increase the
- number of unique case node targets seen. */
- if (!seen_labels.add (lab))
- uniq++;
-
- /* The bounds on the case range, LOW and HIGH, have to be converted
- to case's index type TYPE. Note that the original type of the
- case index in the source code is usually "lost" during
- gimplification due to type promotion, but the case labels retain the
- original type. Make sure to drop overflow flags. */
- low = fold_convert (index_type, low);
- if (TREE_OVERFLOW (low))
- low = wide_int_to_tree (index_type, low);
-
- /* The canonical from of a case label in GIMPLE is that a simple case
- has an empty CASE_HIGH. For the casesi and tablejump expanders,
- the back ends want simple cases to have high == low. */
- if (!high)
- high = low;
- high = fold_convert (index_type, high);
- if (TREE_OVERFLOW (high))
- high = wide_int_to_tree (index_type, high);
+ /* Count the number of entries on branch. Also count the ranges. */
- basic_block case_bb = label_to_block_fn (cfun, lab);
- edge case_edge = find_edge (bb, case_bb);
- case_list = add_case_node (
- case_list, low, high, case_bb, lab,
- case_edge->probability.apply_scale (1, (intptr_t) (case_edge->aux)),
- case_node_pool);
+ while (np)
+ {
+ if (!tree_int_cst_equal (np->m_c->get_low (), np->m_c->get_high ()))
+ ranges++;
- case_bbs.safe_push (case_bb);
- }
- reset_out_edges_aux (bb);
- record_phi_operand_mapping (case_bbs, bb, &phi_mapping);
+ i++;
+ np = np->m_right;
+ }
- /* cleanup_tree_cfg removes all SWITCH_EXPR with a single
- destination, such as one with a default case only.
- It also removes cases that are out of range for the switch
- type, so we should never get a zero here. */
- gcc_assert (count > 0);
+ if (i > 2)
+ {
+ /* Split this list if it is long enough for that to help. */
+ npp = head;
+ left = *npp;
- /* Decide how to expand this switch.
- The two options at this point are a dispatch table (casesi or
- tablejump) or a decision tree. */
+ /* If there are just three nodes, split at the middle one. */
+ if (i == 3)
+ npp = &(*npp)->m_right;
+ else
+ {
+ /* Find the place in the list that bisects the list's total cost,
+ where ranges count as 2.
+ Here I gets half the total cost. */
+ i = (i + ranges + 1) / 2;
+ while (1)
+ {
+ /* Skip nodes while their cost does not reach that amount. */
+ if (!tree_int_cst_equal ((*npp)->m_c->get_low (),
+ (*npp)->m_c->get_high ()))
+ i--;
+ i--;
+ if (i <= 0)
+ break;
+ npp = &(*npp)->m_right;
+ }
+ }
+ *head = np = *npp;
+ *npp = 0;
+ np->m_parent = parent;
+ np->m_left = left;
- if (expand_switch_as_decision_tree_p (range, uniq, count))
- {
- emit_case_decision_tree (stmt, index_expr, index_type, case_list,
- default_bb, default_label, default_prob,
- &phi_mapping);
- return true;
+ /* Optimize each of the two split parts. */
+ balance_case_nodes (&np->m_left, np);
+ balance_case_nodes (&np->m_right, np);
+ np->m_c->m_subtree_prob = np->m_c->m_prob;
+ np->m_c->m_subtree_prob += np->m_left->m_c->m_subtree_prob;
+ np->m_c->m_subtree_prob += np->m_right->m_c->m_subtree_prob;
+ }
+ else
+ {
+ /* Else leave this branch as one level,
+ but fill in `parent' fields. */
+ np = *head;
+ np->m_parent = parent;
+ np->m_c->m_subtree_prob = np->m_c->m_prob;
+ for (; np->m_right; np = np->m_right)
+ {
+ np->m_right->m_parent = np;
+ (*head)->m_c->m_subtree_prob += np->m_right->m_c->m_subtree_prob;
+ }
+ }
}
+}
+
+gimple_opt_pass *
+make_pass_convert_switch (gcc::context *ctxt)
+{
+ return new pass_convert_switch (ctxt);
+}
+
+/* Dump ROOT, a list or tree of case nodes, to file. */
+
+void
+switch_decision_tree::dump_case_nodes (FILE *f, case_tree_node *root,
+ int indent_step, int indent_level)
+{
+ if (root == 0)
+ return;
+ indent_level++;
+
+ dump_case_nodes (f, root->m_left, indent_step, indent_level);
+
+ fputs (";; ", f);
+ fprintf (f, "%*s", indent_step * indent_level, "");
+ root->m_c->dump (f);
+ root->m_c->m_prob.dump (f);
+ fputs ("\n", f);
+
+ dump_case_nodes (f, root->m_right, indent_step, indent_level);
+}
- return false;
+void
+switch_decision_tree::emit_jump (basic_block bb, basic_block case_bb)
+{
+ edge e = single_succ_edge (bb);
+ redirect_edge_succ (e, case_bb);
}
/* The main function of the pass scans statements for switches and invokes
@@ -2200,23 +1839,35 @@ pass_lower_switch<O0>::execute (function *fun)
basic_block bb;
bool expanded = false;
+ auto_vec<gimple *> switch_statements;
+ switch_statements.create (1);
+
FOR_EACH_BB_FN (bb, fun)
{
gimple *stmt = last_stmt (bb);
if (stmt && gimple_code (stmt) == GIMPLE_SWITCH)
+ switch_statements.safe_push (stmt);
+ }
+
+ for (unsigned i = 0; i < switch_statements.length (); i++)
+ {
+ gimple *stmt = switch_statements[i];
+ if (dump_file)
{
- if (dump_file)
- {
- expanded_location loc = expand_location (gimple_location (stmt));
+ expanded_location loc = expand_location (gimple_location (stmt));
- fprintf (dump_file, "beginning to process the following "
- "SWITCH statement (%s:%d) : ------- \n",
- loc.file, loc.line);
- print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
- putc ('\n', dump_file);
- }
+ fprintf (dump_file, "beginning to process the following "
+ "SWITCH statement (%s:%d) : ------- \n",
+ loc.file, loc.line);
+ print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+ putc ('\n', dump_file);
+ }
- expanded |= try_switch_expansion (as_a<gswitch *> (stmt));
+ gswitch *swtch = dyn_cast<gswitch *> (stmt);
+ if (swtch)
+ {
+ switch_decision_tree dt (swtch);
+ expanded |= dt.analyze_switch_statement ();
}
}
@@ -2243,31 +1894,15 @@ make_pass_lower_switch (gcc::context *ctxt)
return new pass_lower_switch<false> (ctxt);
}
-/* Generate code to compare X with Y so that the condition codes are
- set and to jump to LABEL if the condition is true. If X is a
- constant and Y is not a constant, then the comparison is swapped to
- ensure that the comparison RTL has the canonical form.
-
- UNSIGNEDP nonzero says that X and Y are unsigned; this matters if they
- need to be widened. UNSIGNEDP is also used to select the proper
- branch condition code.
-
- If X and Y have mode BLKmode, then SIZE specifies the size of both X and Y.
-
- MODE is the mode of the inputs (in case they are const_int).
-
- COMPARISON is the rtl operator to compare with (EQ, NE, GT, etc.).
- It will be potentially converted into an unsigned variant based on
- UNSIGNEDP to select a proper jump instruction.
-
- PROB is the probability of jumping to LABEL. */
-
-static basic_block
-emit_cmp_and_jump_insns (basic_block bb, tree op0, tree op1,
- tree_code comparison, basic_block label_bb,
- profile_probability prob,
- hash_map<tree, tree> *phi_mapping)
+basic_block
+switch_decision_tree::emit_cmp_and_jump_insns (basic_block bb, tree op0,
+ tree op1, tree_code comparison,
+ basic_block label_bb,
+ profile_probability prob)
{
+ // TODO: it's once called with lhs != index.
+ op1 = fold_convert (TREE_TYPE (op0), op1);
+
gcond *cond = gimple_build_cond (comparison, op0, op1, NULL_TREE, NULL_TREE);
gimple_stmt_iterator gsi = gsi_last_bb (bb);
gsi_insert_after (&gsi, cond, GSI_NEW_STMT);
@@ -2280,36 +1915,16 @@ emit_cmp_and_jump_insns (basic_block bb, tree op0, tree op1,
false_edge->probability = prob.invert ();
edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE);
- fix_phi_operands_for_edge (true_edge, phi_mapping);
true_edge->probability = prob;
return false_edge->dest;
}
-/* Computes the conditional probability of jumping to a target if the branch
- instruction is executed.
- TARGET_PROB is the estimated probability of jumping to a target relative
- to some basic block BB.
- BASE_PROB is the probability of reaching the branch instruction relative
- to the same basic block BB. */
-
-static inline profile_probability
-conditional_probability (profile_probability target_prob,
- profile_probability base_prob)
-{
- return target_prob / base_prob;
-}
-
-/* Emit step-by-step code to select a case for the value of INDEX.
- The thus generated decision tree follows the form of the
- case-node binary tree NODE, whose nodes represent test conditions.
- INDEX_TYPE is the type of the index of the switch. */
-
-static basic_block
-emit_case_nodes (basic_block bb, tree index, case_node_ptr node,
- basic_block default_bb, tree default_label,
- profile_probability default_prob, tree index_type,
- hash_map<tree, tree> *phi_mapping)
+basic_block
+switch_decision_tree::emit_case_nodes (basic_block bb, tree index,
+ case_tree_node *node,
+ profile_probability default_prob,
+ tree index_type)
{
/* If node is null, we are done. */
if (node == NULL)
@@ -2321,34 +1936,31 @@ emit_case_nodes (basic_block bb, tree index, case_node_ptr node,
single_succ_edge (bb)->dest);
profile_probability probability
- = node->right ? node->right->subtree_prob : profile_probability::never ();
- probability
- = conditional_probability (probability + default_prob.apply_scale (1, 2),
- node->subtree_prob + default_prob);
- bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR,
- test_bb, probability, phi_mapping);
+ = (node->m_right
+ ? node->m_right->m_c->m_subtree_prob : profile_probability::never ());
+ probability = ((probability + default_prob.apply_scale (1, 2))
+ / (node->m_c->m_subtree_prob + default_prob));
+ bb = emit_cmp_and_jump_insns (bb, index, node->m_c->get_high (), GT_EXPR,
+ test_bb, probability);
default_prob = default_prob.apply_scale (1, 2);
/* Value belongs to this node or to the left-hand subtree. */
- probability
- = conditional_probability (node->prob, node->subtree_prob + default_prob);
- bb = emit_cmp_and_jump_insns (bb, index, node->low, GE_EXPR,
- node->case_bb, probability,
- phi_mapping);
+ probability = node->m_c->m_prob /
+ (node->m_c->m_subtree_prob + default_prob);
+ bb = emit_cmp_and_jump_insns (bb, index, node->m_c->get_low (), GE_EXPR,
+ node->m_c->m_case_bb, probability);
/* Handle the left-hand subtree. */
- bb = emit_case_nodes (bb, index, node->left, default_bb,
- default_label, default_prob, index_type,
- phi_mapping);
+ bb = emit_case_nodes (bb, index, node->m_left,
+ default_prob, index_type);
/* If the left-hand subtree fell through,
don't let it fall into the right-hand subtree. */
- if (default_bb)
- emit_jump (bb, default_bb, phi_mapping);
+ if (m_default_bb)
+ emit_jump (bb, m_default_bb);
- bb = emit_case_nodes (test_bb, index, node->right, default_bb,
- default_label, default_prob, index_type,
- phi_mapping);
+ bb = emit_case_nodes (test_bb, index, node->m_right,
+ default_prob, index_type);
return bb;
}
diff --git a/gcc/tree-switch-conversion.h b/gcc/tree-switch-conversion.h
new file mode 100644
index 00000000000..45ae11f408d
--- /dev/null
+++ b/gcc/tree-switch-conversion.h
@@ -0,0 +1,806 @@
+/* Tree switch conversion for GNU compiler.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#ifndef TREE_SWITCH_CONVERSION_H
+#define TREE_SWITCH_CONVERSION_H
+
+namespace tree_switch_conversion {
+
+/* Type of cluster. */
+
+enum cluster_type
+{
+ SIMPLE_CASE,
+ JUMP_TABLE,
+ BIT_TEST
+};
+
+#define PRINT_CASE(f,c) print_dec (c, f, TYPE_SIGN (TREE_TYPE (c)))
+
+/* Base class for switch clustering. */
+
+struct cluster
+{
+ /* Cosntructor. */
+ cluster ()
+ {}
+
+ /* Constructor. */
+ cluster (tree case_label_expr, basic_block case_bb, profile_probability prob,
+ profile_probability subtree_prob);
+
+ /* Destructor. */
+ virtual ~cluster ()
+ {}
+
+ /* Return type. */
+ virtual cluster_type get_type () = 0;
+
+ /* Get low value covered by a cluster. */
+ virtual tree get_low () = 0;
+
+ /* Get high value covered by a cluster. */
+ virtual tree get_high () = 0;
+
+ /* Debug content of a cluster. */
+ virtual void debug () = 0;
+
+ /* Dump content of a cluster. */
+ virtual void dump (FILE *f) = 0;
+
+ /* Emit GIMPLE code to handle the cluster. */
+ virtual void emit (tree, tree, tree, basic_block)
+ {}
+
+ /* Return range of a cluster. */
+ static unsigned HOST_WIDE_INT get_range (tree low, tree high)
+ {
+ tree unsigned_type = unsigned_type_for (TREE_TYPE (low));
+ tree r = fold_build2 (MINUS_EXPR, unsigned_type, high, low);
+
+ return tree_to_uhwi (r) + 1;
+ }
+
+ /* Case label. */
+ tree m_case_label_expr;
+
+ /* Basic block of the case. */
+ basic_block m_case_bb;
+
+ /* Probability of taking this cluster. */
+ profile_probability m_prob;
+
+ /* Probability of reaching subtree rooted at this node. */
+ profile_probability m_subtree_prob;
+};
+
+cluster::cluster (tree case_label_expr, basic_block case_bb,
+ profile_probability prob, profile_probability subtree_prob):
+ m_case_label_expr (case_label_expr), m_case_bb (case_bb), m_prob (prob),
+ m_subtree_prob (subtree_prob)
+{
+}
+
+struct simple_cluster: public cluster
+{
+ /* Constructor. */
+ simple_cluster (tree low, tree high, tree case_label_expr,
+ basic_block case_bb, profile_probability prob);
+
+ /* Destructor. */
+ virtual ~simple_cluster ()
+ {}
+
+ virtual cluster_type
+ get_type ()
+ {
+ return SIMPLE_CASE;
+ }
+
+ virtual tree
+ get_low ()
+ {
+ return m_low;
+ }
+
+ virtual tree
+ get_high ()
+ {
+ return m_high;
+ }
+
+ virtual void
+ debug ()
+ {
+ dump (stderr);
+ }
+
+ virtual void
+ dump (FILE *f)
+ {
+ PRINT_CASE (f, get_low ());
+ if (get_low () != get_high ())
+ {
+ fprintf (f, "-");
+ PRINT_CASE (f, get_high ());
+ }
+ fprintf (f, " ");
+ }
+
+ /* Low value of the case. */
+ tree m_low;
+
+ /* High value of the case. */
+ tree m_high;
+};
+
+simple_cluster::simple_cluster (tree low, tree high, tree case_label_expr,
+ basic_block case_bb, profile_probability prob):
+ cluster (case_label_expr, case_bb, prob, prob),
+ m_low (low), m_high (high)
+{
+}
+
+struct group_cluster: public cluster
+{
+ /* Destructor. */
+ virtual ~group_cluster ();
+
+ virtual tree
+ get_low ()
+ {
+ return m_cases[0]->get_low ();
+ }
+
+ virtual tree
+ get_high ()
+ {
+ return m_cases[m_cases.length () - 1]->get_high ();
+ }
+
+ virtual void
+ debug ()
+ {
+ dump (stderr);
+ }
+
+ virtual void
+ dump (FILE *f)
+ {
+ unsigned total_values = 0;
+ for (unsigned i = 0; i < m_cases.length (); i++)
+ total_values += m_cases[i]->get_range (m_cases[i]->get_low (),
+ m_cases[i]->get_high ());
+
+ fprintf (f, "%s(%d):", get_type () == JUMP_TABLE ? "JT" : "BT",
+ total_values);
+ PRINT_CASE (f, get_low ());
+ fprintf (f, "-");
+ PRINT_CASE (f, get_high ());
+ fprintf (f, " ");
+ }
+
+ /* List of simple clusters handled by the group. */
+ vec<simple_cluster *> m_cases;
+};
+
+struct jump_table_cluster: public group_cluster
+{
+ /* Constructor. */
+ jump_table_cluster (vec<cluster *> &clusters, unsigned start, unsigned end);
+
+ virtual cluster_type
+ get_type ()
+ {
+ return JUMP_TABLE;
+ }
+
+ virtual void emit (tree index_expr, tree index_type,
+ tree default_label_expr, basic_block default_bb);
+
+ /* Find jump tables of given CLUSTERS, where all members of the vector
+ are of type simple_cluster. New clusters are returned. */
+ static vec<cluster *> find_jump_tables (vec<cluster *> &clusters);
+
+ /* Return true when cluster starting at START and ending at END (inclusive)
+ can build a jump-table. */
+ static bool can_be_handled (const vec<cluster *> &clusters, unsigned start,
+ unsigned end);
+
+ /* Return true if cluster starting at START and ending at END (inclusive)
+ is profitable transformation. */
+ static bool is_beneficial (const vec<cluster *> &clusters, unsigned start,
+ unsigned end);
+
+ /* Return the smallest number of different values for which it is best
+ to use a jump-table instead of a tree of conditional branches. */
+ static inline unsigned int case_values_threshold (void);
+};
+
+/* A GIMPLE switch statement can be expanded to a short sequence of bit-wise
+comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)"
+where CST and MINVAL are integer constants. This is better than a series
+of compare-and-banch insns in some cases, e.g. we can implement:
+
+ if ((x==4) || (x==6) || (x==9) || (x==11))
+
+as a single bit test:
+
+ if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11)))
+
+This transformation is only applied if the number of case targets is small,
+if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are
+performed in "word_mode".
+
+The following example shows the code the transformation generates:
+
+ int bar(int x)
+ {
+ switch (x)
+ {
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+ case 'A': case 'B': case 'C': case 'D': case 'E':
+ case 'F':
+ return 1;
+ }
+ return 0;
+ }
+
+==>
+
+ bar (int x)
+ {
+ tmp1 = x - 48;
+ if (tmp1 > (70 - 48)) goto L2;
+ tmp2 = 1 << tmp1;
+ tmp3 = 0b11111100000001111111111;
+ if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2;
+ L1:
+ return 1;
+ L2:
+ return 0;
+ }
+
+TODO: There are still some improvements to this transformation that could
+be implemented:
+
+* A narrower mode than word_mode could be used if that is cheaper, e.g.
+ for x86_64 where a narrower-mode shift may result in smaller code.
+
+* The compounded constant could be shifted rather than the one. The
+ test would be either on the sign bit or on the least significant bit,
+ depending on the direction of the shift. On some machines, the test
+ for the branch would be free if the bit to test is already set by the
+ shift operation.
+
+This transformation was contributed by Roger Sayle, see this e-mail:
+ http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html
+*/
+
+struct bit_test_cluster: public group_cluster
+{
+ /* Constructor. */
+ bit_test_cluster (vec<cluster *> &clusters, unsigned start, unsigned end);
+
+ virtual cluster_type
+ get_type ()
+ {
+ return BIT_TEST;
+ }
+
+/* Expand a switch statement by a short sequence of bit-wise
+ comparisons. "switch(x)" is effectively converted into
+ "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
+ integer constants.
+
+ INDEX_EXPR is the value being switched on.
+
+ MINVAL is the lowest case value of in the case nodes,
+ and RANGE is highest value minus MINVAL. MINVAL and RANGE
+ are not guaranteed to be of the same type as INDEX_EXPR
+ (the gimplifier doesn't change the type of case label values,
+ and MINVAL and RANGE are derived from those values).
+ MAXVAL is MINVAL + RANGE.
+
+ There *MUST* be max_case_bit_tests or less unique case
+ node targets. */
+ virtual void emit (tree index_expr, tree index_type,
+ tree default_label_expr, basic_block default_bb);
+
+ /* Find bit tests of given CLUSTERS, where all members of the vector
+ are of type simple_cluster. New clusters are returned. */
+ static vec<cluster *> find_bit_tests (vec<cluster *> &clusters);
+
+ /* Return true when cluster starting at START and ending at END (inclusive)
+ can build a bit test. */
+ static bool can_be_handled (const vec<cluster *> &clusters, unsigned start,
+ unsigned end);
+
+ /* Return true if cluster starting at START and ending at END (inclusive)
+ is profitable transformation. */
+ static bool is_beneficial (const vec<cluster *> &clusters, unsigned start,
+ unsigned end);
+
+/* Split the basic block at the statement pointed to by GSIP, and insert
+ a branch to the target basic block of E_TRUE conditional on tree
+ expression COND.
+
+ It is assumed that there is already an edge from the to-be-split
+ basic block to E_TRUE->dest block. This edge is removed, and the
+ profile information on the edge is re-used for the new conditional
+ jump.
+
+ The CFG is updated. The dominator tree will not be valid after
+ this transformation, but the immediate dominators are updated if
+ UPDATE_DOMINATORS is true.
+
+ Returns the newly created basic block. */
+ static basic_block hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip,
+ tree cond,
+ basic_block case_bb);
+
+ /* Maximum number of different basic blocks that can be handlel by
+ a bit test. */
+ static const int m_max_case_bit_tests = 3;
+};
+
+/* Helper struct to find minimal clusters. */
+
+struct min_cluster_item
+{
+ /* Constructor. */
+ min_cluster_item (unsigned count, unsigned start, unsigned non_jt_cases):
+ m_count (count), m_start (start), m_non_jt_cases (non_jt_cases)
+ {}
+
+ /* Count of clusters. */
+ unsigned m_count;
+
+ /* Index where is cluster boundary. */
+ unsigned m_start;
+
+ /* Total number of cases that will not be in a jump table. */
+ unsigned m_non_jt_cases;
+};
+
+/* Helper struct to represent switch decision tree. */
+
+struct case_tree_node
+{
+ /* Empty Constructor. */
+ case_tree_node ();
+
+ /* Left son in binary tree. */
+ case_tree_node *m_left;
+
+ /* Right son in binary tree; also node chain. */
+ case_tree_node *m_right;
+
+ /* Parent of node in binary tree. */
+ case_tree_node *m_parent;
+
+ /* Cluster represented by this tree node. */
+ cluster *m_c;
+};
+
+inline
+case_tree_node::case_tree_node ():
+ m_left (NULL), m_right (NULL), m_parent (NULL), m_c (NULL)
+{
+}
+
+unsigned int
+jump_table_cluster::case_values_threshold (void)
+{
+ unsigned int threshold = PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD);
+
+ if (threshold == 0)
+ threshold = targetm.case_values_threshold ();
+
+ return threshold;
+}
+
+/* A case_bit_test represents a set of case nodes that may be
+ selected from using a bit-wise comparison. HI and LO hold
+ the integer to be tested against, TARGET_EDGE contains the
+ edge to the basic block to jump to upon success and BITS
+ counts the number of case nodes handled by this test,
+ typically the number of bits set in HI:LO. The LABEL field
+ is used to quickly identify all cases in this set without
+ looking at label_to_block for every case label. */
+
+struct case_bit_test
+{
+ wide_int mask;
+ basic_block target_bb;
+ tree label;
+ int bits;
+
+ /* Comparison function for qsort to order bit tests by decreasing
+ probability of execution. */
+ static int cmp (const void *p1, const void *p2);
+};
+
+struct switch_decision_tree
+{
+ /* Constructor. */
+ switch_decision_tree (gswitch *swtch): m_switch (swtch), m_phi_mapping (),
+ m_case_bbs (), m_case_node_pool ("struct case_node pool"),
+ m_case_list (NULL)
+ {
+ }
+
+ /* Analyze switch statement and return true when the statement is expanded
+ as decision tree. */
+ bool analyze_switch_statement ();
+
+ /* Attempt to expand CLUSTERS as a decision tree. Return true when
+ expanded. */
+ bool try_switch_expansion (vec<cluster *> &clusters);
+
+ /* Reset the aux field of all outgoing edges of switch basic block. */
+ inline void reset_out_edges_aux ();
+
+ /* Compute the number of case labels that correspond to each outgoing edge of
+ switch statement. Record this information in the aux field of the edge.
+ */
+ void compute_cases_per_edge ();
+
+ /* Before switch transformation, record all SSA_NAMEs defined in switch BB
+ and used in a label basic block. */
+ void record_phi_operand_mapping ();
+
+ /* Append new operands to PHI statements that were introduced due to
+ addition of new edges to case labels. */
+ void fix_phi_operands_for_edges ();
+
+ /* Generate a decision tree, switching on INDEX_EXPR and jumping to
+ one of the labels in CASE_LIST or to the DEFAULT_LABEL.
+
+ We generate a binary decision tree to select the appropriate target
+ code. */
+
+ void emit (basic_block bb, tree index_expr,
+ profile_probability default_prob, tree index_type);
+
+ /* Emit step-by-step code to select a case for the value of INDEX.
+ The thus generated decision tree follows the form of the
+ case-node binary tree NODE, whose nodes represent test conditions.
+ DEFAULT_PROB is probability of cases leading to default BB.
+ INDEX_TYPE is the type of the index of the switch. */
+ basic_block emit_case_nodes (basic_block bb, tree index,
+ case_tree_node *node,
+ profile_probability default_prob,
+ tree index_type);
+
+ /* Take an ordered list of case nodes
+ and transform them into a near optimal binary tree,
+ on the assumption that any target code selection value is as
+ likely as any other.
+
+ The transformation is performed by splitting the ordered
+ list into two equal sections plus a pivot. The parts are
+ then attached to the pivot as left and right branches. Each
+ branch is then transformed recursively. */
+ static void balance_case_nodes (case_tree_node **head,
+ case_tree_node *parent);
+
+ /* Dump ROOT, a list or tree of case nodes, to file F. */
+ static void dump_case_nodes (FILE *f, case_tree_node *root, int indent_step,
+ int indent_level);
+
+ /* Add an unconditional jump to CASE_BB that happens in basic block BB. */
+ static void emit_jump (basic_block bb, basic_block case_bb);
+
+ /* Generate code to compare OP0 with OP1 so that the condition codes are
+ set and to jump to LABEL_BB if the condition is true.
+ COMPARISON is the GIMPLE comparison (EQ, NE, GT, etc.).
+ PROB is the probability of jumping to LABEL_BB. */
+
+ static basic_block emit_cmp_and_jump_insns (basic_block bb, tree op0,
+ tree op1, tree_code comparison,
+ basic_block label_bb,
+ profile_probability prob);
+
+ /* Switch statement. */
+ gswitch *m_switch;
+
+ /* Map of PHI nodes that have to be fixed after expansion. */
+ hash_map<tree, tree> m_phi_mapping;
+
+ /* List of basic blocks that belong to labels of the switch. */
+ auto_vec<basic_block> m_case_bbs;
+
+ /* Basic block with default label. */
+ basic_block m_default_bb;
+
+ /* A pool for case nodes. */
+ object_allocator<case_tree_node> m_case_node_pool;
+
+ /* Balanced tree of case nodes. */
+ case_tree_node *m_case_list;
+};
+
+/*
+ Switch initialization conversion
+
+The following pass changes simple initializations of scalars in a switch
+statement into initializations from a static array. Obviously, the values
+must be constant and known at compile time and a default branch must be
+provided. For example, the following code:
+
+ int a,b;
+
+ switch (argc)
+ {
+ case 1:
+ case 2:
+ a_1 = 8;
+ b_1 = 6;
+ break;
+ case 3:
+ a_2 = 9;
+ b_2 = 5;
+ break;
+ case 12:
+ a_3 = 10;
+ b_3 = 4;
+ break;
+ default:
+ a_4 = 16;
+ b_4 = 1;
+ break;
+ }
+ a_5 = PHI <a_1, a_2, a_3, a_4>
+ b_5 = PHI <b_1, b_2, b_3, b_4>
+
+
+is changed into:
+
+ static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4};
+ static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16,
+ 16, 16, 10};
+
+ if (((unsigned) argc) - 1 < 11)
+ {
+ a_6 = CSWTCH02[argc - 1];
+ b_6 = CSWTCH01[argc - 1];
+ }
+ else
+ {
+ a_7 = 16;
+ b_7 = 1;
+ }
+ a_5 = PHI <a_6, a_7>
+ b_b = PHI <b_6, b_7>
+
+There are further constraints. Specifically, the range of values across all
+case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default
+eight) times the number of the actual switch branches.
+
+This transformation was contributed by Martin Jambor, see this e-mail:
+ http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */
+
+/* The main structure of the pass. */
+struct switch_conversion
+{
+ /* Constructor. */
+ switch_conversion ();
+
+ /* Destructor. */
+ ~switch_conversion ();
+
+ /* The following function is invoked on every switch statement (the current
+ one is given in SWTCH) and runs the individual phases of switch
+ conversion on it one after another until one fails or the conversion
+ is completed. Returns NULL on success, or a pointer to a string
+ with the reason why the conversion failed. */
+ const char *expand (gswitch *swtch);
+
+ /* Collection information about SWTCH statement. */
+ void collect (gswitch *swtch);
+
+ /* Checks whether the range given by individual case statements of the switch
+ switch statement isn't too big and whether the number of branches actually
+ satisfies the size of the new array. */
+ bool check_range ();
+
+ /* Checks whether all but the final BB basic blocks are empty. */
+ bool check_all_empty_except_final ();
+
+ /* This function checks whether all required values in phi nodes in final_bb
+ are constants. Required values are those that correspond to a basic block
+ which is a part of the examined switch statement. It returns true if the
+ phi nodes are OK, otherwise false. */
+ bool check_final_bb ();
+
+ /* The following function allocates default_values, target_{in,out}_names and
+ constructors arrays. The last one is also populated with pointers to
+ vectors that will become constructors of new arrays. */
+ void create_temp_arrays ();
+
+ /* Populate the array of default values in the order of phi nodes.
+ DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch
+ if the range is non-contiguous or the default case has standard
+ structure, otherwise it is the first non-default case instead. */
+ void gather_default_values (tree default_case);
+
+ /* The following function populates the vectors in the constructors array with
+ future contents of the static arrays. The vectors are populated in the
+ order of phi nodes. */
+ void build_constructors ();
+
+ /* If all values in the constructor vector are the same, return the value.
+ Otherwise return NULL_TREE. Not supposed to be called for empty
+ vectors. */
+ tree contains_same_values_p (vec<constructor_elt, va_gc> *vec);
+
+ /* Return type which should be used for array elements, either TYPE's
+ main variant or, for integral types, some smaller integral type
+ that can still hold all the constants. */
+ tree array_value_type (tree type, int num);
+
+ /* Create an appropriate array type and declaration and assemble a static
+ array variable. Also create a load statement that initializes
+ the variable in question with a value from the static array. SWTCH is
+ the switch statement being converted, NUM is the index to
+ arrays of constructors, default values and target SSA names
+ for this particular array. ARR_INDEX_TYPE is the type of the index
+ of the new array, PHI is the phi node of the final BB that corresponds
+ to the value that will be loaded from the created array. TIDX
+ is an ssa name of a temporary variable holding the index for loads from the
+ new array. */
+ void build_one_array (int num, tree arr_index_type,
+ gphi *phi, tree tidx);
+
+ /* Builds and initializes static arrays initialized with values gathered from
+ the switch statement. Also creates statements that load values from
+ them. */
+ void build_arrays ();
+
+ /* Generates and appropriately inserts loads of default values at the position
+ given by GSI. Returns the last inserted statement. */
+ gassign *gen_def_assigns (gimple_stmt_iterator *gsi);
+
+ /* Deletes the unused bbs and edges that now contain the switch statement and
+ its empty branch bbs. BBD is the now dead BB containing
+ the original switch statement, FINAL is the last BB of the converted
+ switch statement (in terms of succession). */
+ void prune_bbs (basic_block bbd, basic_block final, basic_block default_bb);
+
+ /* Add values to phi nodes in final_bb for the two new edges. E1F is the edge
+ from the basic block loading values from an array and E2F from the basic
+ block loading default values. BBF is the last switch basic block (see the
+ bbf description in the comment below). */
+ void fix_phi_nodes (edge e1f, edge e2f, basic_block bbf);
+
+ /* Creates a check whether the switch expression value actually falls into the
+ range given by all the cases. If it does not, the temporaries are loaded
+ with default values instead. SWTCH is the switch statement being
+ converted.
+
+ bb0 is the bb with the switch statement, however, we'll end it with a
+ condition instead.
+
+ bb1 is the bb to be used when the range check went ok. It is derived from
+ the switch BB
+
+ bb2 is the bb taken when the expression evaluated outside of the range
+ covered by the created arrays. It is populated by loads of default
+ values.
+
+ bbF is a fall through for both bb1 and bb2 and contains exactly what
+ originally followed the switch statement.
+
+ bbD contains the switch statement (in the end). It is unreachable but we
+ still need to strip off its edges. */
+ void gen_inbound_check ();
+
+ /* Switch statement for which switch conversion takes place. */
+ gswitch *m_switch;
+
+ /* The expression used to decide the switch branch. */
+ tree m_index_expr;
+
+ /* The following integer constants store the minimum and maximum value
+ covered by the case labels. */
+ tree m_range_min;
+ tree m_range_max;
+
+ /* The difference between the above two numbers. Stored here because it
+ is used in all the conversion heuristics, as well as for some of the
+ transformation, and it is expensive to re-compute it all the time. */
+ tree m_range_size;
+
+ /* Basic block that contains the actual GIMPLE_SWITCH. */
+ basic_block m_switch_bb;
+
+ /* Basic block that is the target of the default case. */
+ basic_block m_default_bb;
+
+ /* The single successor block of all branches out of the GIMPLE_SWITCH,
+ if such a block exists. Otherwise NULL. */
+ basic_block m_final_bb;
+
+ /* The probability of the default edge in the replaced switch. */
+ profile_probability m_default_prob;
+
+ /* The count of the default edge in the replaced switch. */
+ profile_count m_default_count;
+
+ /* Combined count of all other (non-default) edges in the replaced switch. */
+ profile_count m_other_count;
+
+ /* Number of phi nodes in the final bb (that we'll be replacing). */
+ int m_phi_count;
+
+ /* Constructors of new static arrays. */
+ vec<constructor_elt, va_gc> **m_constructors;
+
+ /* Array of default values, in the same order as phi nodes. */
+ tree *m_default_values;
+
+ /* Array of ssa names that are initialized with a value from a new static
+ array. */
+ tree *m_target_inbound_names;
+
+ /* Array of ssa names that are initialized with the default value if the
+ switch expression is out of range. */
+ tree *m_target_outbound_names;
+
+ /* VOP SSA_NAME. */
+ tree m_target_vop;
+
+ /* The first load statement that loads a temporary from a new static array.
+ */
+ gimple *m_arr_ref_first;
+
+ /* The last load statement that loads a temporary from a new static array. */
+ gimple *m_arr_ref_last;
+
+ /* String reason why the case wasn't a good candidate that is written to the
+ dump file, if there is one. */
+ const char *m_reason;
+
+ /* True if default case is not used for any value between range_min and
+ range_max inclusive. */
+ bool m_contiguous_range;
+
+ /* True if default case does not have the required shape for other case
+ labels. */
+ bool m_default_case_nonstandard;
+
+ /* Count is number of non-default edges. */
+ unsigned int m_count;
+};
+
+void
+switch_decision_tree::reset_out_edges_aux ()
+{
+ basic_block bb = gimple_bb (m_switch);
+ edge e;
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ e->aux = (void *) 0;
+}
+
+} // tree_switch_conversion namespace
+
+#endif // TREE_SWITCH_CONVERSION_H
diff --git a/gcc/vec.h b/gcc/vec.h
index cbdd439571b..72a9f4b106a 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -1263,6 +1263,7 @@ public:
T *bsearch (const void *key, int (*compar)(const void *, const void *));
unsigned lower_bound (T, bool (*)(const T &, const T &)) const;
bool contains (const T &search) const;
+ void reverse (void);
bool using_auto_storage () const;
@@ -1774,6 +1775,19 @@ vec<T, va_heap, vl_ptr>::contains (const T &search) const
return m_vec ? m_vec->contains (search) : false;
}
+/* Reverse content of the vector. */
+
+template<typename T>
+inline void
+vec<T, va_heap, vl_ptr>::reverse (void)
+{
+ unsigned l = length ();
+ T *ptr = address ();
+
+ for (unsigned i = 0; i < l / 2; i++)
+ std::swap (ptr[i], ptr[l - i - 1]);
+}
+
template<typename T>
inline bool
vec<T, va_heap, vl_ptr>::using_auto_storage () const
--
2.14.2
