Hi!
The following testcases show two bugs in zero_one_operation (used during
undistribute optimization) and functions it calls.
The first one (wrong-code) is fixed by the
+ tree orig_def = *def;
and
- if (stmts_to_fix.length () > 0)
+ if (stmts_to_fix.length () > 0 || *def == orig_def)
changes in zero_one_operation - e.g. in the testcase we have before reassoc
_6 = _5 * a_11;
_7 = _5 * _6;
and call zero_one_operation for _7 with op a_11. The last stmt isn't pushed
into stmts_to_fix, the *def stmt is handled specially in
make_new_ssa_for_all_defs. And the previous one, while it is pushed, it is
popped from there again, because the stmt is removed and instead _6 use
is replaced with _5. That changes what value _7 holds, so we want to use
a new SSA_NAME for it (or deal with debug stmts and reset flow sensitive
info etc.).
The second one is wrong-debug, make_new_ssa_for_def replaces the uses of old
lhs with the new lhs (which is fine in the code uses, but for debug info
because we zeroed out a_11 we want to say that previous uses of _7 are now
the _7's replacement * a_11. Which is what the rest of the patch does
and there is a guality testcase that verifies it (previously it would fail).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2016-12-08 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/78726
* tree-ssa-reassoc.c (make_new_ssa_for_def): Add OPCODE and OP
argument. For lhs uses in debug stmts, don't replace lhs with
new_lhs, but with a debug temp set to new_lhs opcode op.
(make_new_ssa_for_all_defs): Add OPCODE argument, pass OPCODE and
OP down to make_new_ssa_for_def.
(zero_one_operation): Call make_new_ssa_for_all_defs even when
stmts_to_fix is empty, if *def has not changed yet. Pass
OPCODE to make_new_ssa_for_all_defs.
* gcc.c-torture/execute/pr78726.c: New test.
* gcc.dg/guality/pr78726.c: New test.
--- gcc/tree-ssa-reassoc.c.jj 2016-11-09 16:34:58.000000000 +0100
+++ gcc/tree-ssa-reassoc.c 2016-12-08 15:53:13.768894146 +0100
@@ -1153,12 +1153,12 @@ decrement_power (gimple *stmt)
SSA. Also return the new SSA. */
static tree
-make_new_ssa_for_def (gimple *stmt)
+make_new_ssa_for_def (gimple *stmt, enum tree_code opcode, tree op)
{
gimple *use_stmt;
use_operand_p use;
imm_use_iterator iter;
- tree new_lhs;
+ tree new_lhs, new_debug_lhs = NULL_TREE;
tree lhs = gimple_get_lhs (stmt);
new_lhs = make_ssa_name (TREE_TYPE (lhs));
@@ -1167,8 +1167,28 @@ make_new_ssa_for_def (gimple *stmt)
/* Also need to update GIMPLE_DEBUGs. */
FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
{
+ tree repl = new_lhs;
+ if (is_gimple_debug (use_stmt))
+ {
+ if (new_debug_lhs == NULL_TREE)
+ {
+ new_debug_lhs = make_node (DEBUG_EXPR_DECL);
+ gdebug *def_temp
+ = gimple_build_debug_bind (new_debug_lhs,
+ build2 (opcode, TREE_TYPE (lhs),
+ new_lhs, op),
+ stmt);
+ DECL_ARTIFICIAL (new_debug_lhs) = 1;
+ TREE_TYPE (new_debug_lhs) = TREE_TYPE (lhs);
+ SET_DECL_MODE (new_debug_lhs, TYPE_MODE (TREE_TYPE (lhs)));
+ gimple_set_uid (def_temp, gimple_uid (stmt));
+ gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
+ gsi_insert_after (&gsi, def_temp, GSI_SAME_STMT);
+ }
+ repl = new_debug_lhs;
+ }
FOR_EACH_IMM_USE_ON_STMT (use, iter)
- SET_USE (use, new_lhs);
+ SET_USE (use, repl);
update_stmt (use_stmt);
}
return new_lhs;
@@ -1179,7 +1199,7 @@ make_new_ssa_for_def (gimple *stmt)
if *DEF is not OP. */
static void
-make_new_ssa_for_all_defs (tree *def, tree op,
+make_new_ssa_for_all_defs (tree *def, enum tree_code opcode, tree op,
vec<gimple *> &stmts_to_fix)
{
unsigned i;
@@ -1189,10 +1209,10 @@ make_new_ssa_for_all_defs (tree *def, tr
&& TREE_CODE (*def) == SSA_NAME
&& (stmt = SSA_NAME_DEF_STMT (*def))
&& gimple_code (stmt) != GIMPLE_NOP)
- *def = make_new_ssa_for_def (stmt);
+ *def = make_new_ssa_for_def (stmt, opcode, op);
FOR_EACH_VEC_ELT (stmts_to_fix, i, stmt)
- make_new_ssa_for_def (stmt);
+ make_new_ssa_for_def (stmt, opcode, op);
}
/* Find the single immediate use of STMT's LHS, and replace it
@@ -1232,6 +1252,7 @@ propagate_op_to_single_use (tree op, gim
static void
zero_one_operation (tree *def, enum tree_code opcode, tree op)
{
+ tree orig_def = *def;
gimple *stmt = SSA_NAME_DEF_STMT (*def);
/* PR72835 - Record the stmt chain that has to be updated such that
we dont use the same LHS when the values computed are different. */
@@ -1335,8 +1356,8 @@ zero_one_operation (tree *def, enum tree
}
while (1);
- if (stmts_to_fix.length () > 0)
- make_new_ssa_for_all_defs (def, op, stmts_to_fix);
+ if (stmts_to_fix.length () > 0 || *def == orig_def)
+ make_new_ssa_for_all_defs (def, opcode, op, stmts_to_fix);
}
/* Returns true if statement S1 dominates statement S2. Like
--- gcc/testsuite/gcc.c-torture/execute/pr78726.c.jj 2016-12-08
15:55:08.847434702 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr78726.c 2016-12-08
15:54:46.000000000 +0100
@@ -0,0 +1,23 @@
+/* PR tree-optimization/78726 */
+
+unsigned char b = 36, c = 173;
+unsigned int d;
+
+__attribute__((noinline, noclone)) void
+foo (void)
+{
+ unsigned a = ~b;
+ d = a * c * c + 1023094746U * a;
+}
+
+int
+main ()
+{
+ if (__SIZEOF_INT__ != 4 || __CHAR_BIT__ != 8)
+ return 0;
+ asm volatile ("" : : "g" (&b), "g" (&c) : "memory");
+ foo ();
+ if (d != 799092689U)
+ __builtin_abort ();
+ return 0;
+}
--- gcc/testsuite/gcc.dg/guality/pr78726.c.jj 2016-12-08 15:57:07.779926381
+0100
+++ gcc/testsuite/gcc.dg/guality/pr78726.c 2016-12-08 16:02:57.216494771
+0100
@@ -0,0 +1,30 @@
+/* PR tree-optimization/78726 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+
+#include "../nop.h"
+
+unsigned char b = 36, c = 173;
+unsigned int d;
+
+__attribute__((noinline, noclone)) void
+foo (void)
+{
+ unsigned a = ~b;
+ unsigned d1 = a * c; /* { dg-final { gdb-test 21 "d1" "~36U * 173" }
} */
+ unsigned d2 = d1 * c; /* { dg-final { gdb-test 21 "d2" "~36U
* 173 * 173" } } */
+ unsigned d3 = 1023094746 * a; /* { dg-final { gdb-test 21 "d3" "~36U
* 1023094746" } } */
+ d = d2 + d3;
+ unsigned d4 = d1 * 2; /* { dg-final { gdb-test 21 "d4" "~36U * 173 *
2" } } */
+ unsigned d5 = d2 * 2; /* { dg-final { gdb-test 21 "d5" "~36U
* 173 * 173 * 2" } } */
+ unsigned d6 = d3 * 2; /* { dg-final { gdb-test 21 "d6" "~36U
* 1023094746 * 2" } } */
+ asm (NOP : : : "memory");
+}
+
+int
+main ()
+{
+ asm volatile ("" : : "g" (&b), "g" (&c) : "memory");
+ foo ();
+ return 0;
+}
Jakub
