Hi!
Two years ago, I've added support for up to 2 simple preparation statements
in value_replacement, but the
- && estimate_num_insns (assign, &eni_time_weights)
+ && estimate_num_insns (bb_seq (middle_bb), &eni_time_weights)
change, meant that we compute the cost of all those statements rather than
just the single assign that has been the single supported non-debug
statement in the bb before, doesn't do what I thought would do, gimple_seq
is just gimple * and thus it can't be really overloaded depending on whether
we pass a single gimple * or a whole sequence. Which means in the last
two years it doesn't count all the statements, but only the first one.
With -g that happens to be a DEBUG_STMT, or it could be e.g. the first
preparation statement which could be much cheaper than the actual assign.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2020-03-19 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/94211
* tree-ssa-phiopt.c (value_replacement): Use estimate_num_insns_seq
instead of estimate_num_insns for bb_seq (middle_bb). Rename
emtpy_or_with_defined_p variable to empty_or_with_defined_p, adjust
all uses.
* gcc.dg/pr94211.c: New test.
--- gcc/tree-ssa-phiopt.c.jj 2020-03-16 23:49:29.853404202 +0100
+++ gcc/tree-ssa-phiopt.c 2020-03-18 19:42:22.583225152 +0100
@@ -1056,7 +1056,7 @@ value_replacement (basic_block cond_bb,
gimple *cond;
edge true_edge, false_edge;
enum tree_code code;
- bool emtpy_or_with_defined_p = true;
+ bool empty_or_with_defined_p = true;
/* If the type says honor signed zeros we cannot do this
optimization. */
@@ -1075,7 +1075,7 @@ value_replacement (basic_block cond_bb,
{
if (gimple_code (stmt) != GIMPLE_PREDICT
&& gimple_code (stmt) != GIMPLE_NOP)
- emtpy_or_with_defined_p = false;
+ empty_or_with_defined_p = false;
continue;
}
/* Now try to adjust arg0 or arg1 according to the computation
@@ -1085,7 +1085,7 @@ value_replacement (basic_block cond_bb,
&& jump_function_from_stmt (&arg0, stmt))
|| (lhs == arg1
&& jump_function_from_stmt (&arg1, stmt)))
- emtpy_or_with_defined_p = false;
+ empty_or_with_defined_p = false;
}
cond = last_stmt (cond_bb);
@@ -1137,7 +1137,7 @@ value_replacement (basic_block cond_bb,
/* If the middle basic block was empty or is defining the
PHI arguments and this is a single phi where the args are different
for the edges e0 and e1 then we can remove the middle basic block. */
- if (emtpy_or_with_defined_p
+ if (empty_or_with_defined_p
&& single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)),
e0, e1) == phi)
{
@@ -1255,7 +1255,7 @@ value_replacement (basic_block cond_bb,
&& profile_status_for_fn (cfun) != PROFILE_ABSENT
&& EDGE_PRED (middle_bb, 0)->probability < profile_probability::even ()
/* If assign is cheap, there is no point avoiding it. */
- && estimate_num_insns (bb_seq (middle_bb), &eni_time_weights)
+ && estimate_num_insns_seq (bb_seq (middle_bb), &eni_time_weights)
>= 3 * estimate_num_insns (cond, &eni_time_weights))
return 0;
--- gcc/testsuite/gcc.dg/pr94211.c.jj 2020-03-18 16:30:34.562427467 +0100
+++ gcc/testsuite/gcc.dg/pr94211.c 2020-03-18 16:30:19.998640206 +0100
@@ -0,0 +1,12 @@
+/* PR tree-optimization/94211 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcompare-debug" } */
+
+long
+foo (long a, long b)
+{
+ if (__builtin_expect (b == 1, 1))
+ return a;
+ int e = a + 1;
+ return a / b;
+}
Jakub
