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[PATCH] Fix cond updating in tree-ssa-dom (PR tree-optimization/77454)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Richard Biener <rguenther at suse dot de>, Jeff Law <law at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 13 Sep 2016 09:46:26 +0200
- Subject: [PATCH] Fix cond updating in tree-ssa-dom (PR tree-optimization/77454)
- Authentication-results: sourceware.org; auth=none
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
The following testcase ICEs because SSA_NAME IMM links are broken.
I've tracked it to DOM's optimize_stmt, a GIMPLE_COND in there is
changed, marked as modified, then in optimize_stmt
if (gimple_modified_p (stmt) || modified_p)
{
tree val = NULL;
update_stmt_if_modified (stmt);
and a few lines later changed again:
if (gimple_code (stmt) == GIMPLE_COND)
{
if (integer_zerop (val))
gimple_cond_make_false (as_a <gcond *> (stmt));
else if (integer_onep (val))
gimple_cond_make_true (as_a <gcond *> (stmt));
without update_stmt. As this is a function which update_stmt_if_modified
a few lines before, I think it is fine to update_stmt it immediately.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2016-09-13 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/77454
* tree-ssa-dom.c (optimize_stmt): Call update_stmt after changing
GIMPLE_COND. Formatting fix.
* gcc.dg/pr77454.c: New test.
--- gcc/tree-ssa-dom.c.jj 2016-07-22 15:55:30.000000000 +0200
+++ gcc/tree-ssa-dom.c 2016-09-09 12:29:28.006188533 +0200
@@ -1927,8 +1927,9 @@ optimize_stmt (basic_block bb, gimple_st
if (gimple_code (stmt) == GIMPLE_COND)
val = fold_binary_loc (gimple_location (stmt),
- gimple_cond_code (stmt), boolean_type_node,
- gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
+ gimple_cond_code (stmt), boolean_type_node,
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt));
else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt))
val = gimple_switch_index (swtch_stmt);
@@ -1946,6 +1947,8 @@ optimize_stmt (basic_block bb, gimple_st
gimple_cond_make_true (as_a <gcond *> (stmt));
else
gcc_unreachable ();
+
+ update_stmt (stmt);
}
/* Further simplifications may be possible. */
--- gcc/testsuite/gcc.dg/pr77454.c.jj 2016-09-09 12:34:47.540537483 +0200
+++ gcc/testsuite/gcc.dg/pr77454.c 2016-09-09 12:32:47.000000000 +0200
@@ -0,0 +1,28 @@
+/* PR tree-optimization/77454 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void
+foo (unsigned char x, char y)
+{
+ while (x != 0)
+ {
+ unsigned char *a = &x;
+ int b;
+
+ if (y != 0)
+ a = (unsigned char *) &y;
+ else if (y + 1 != 0)
+ a = (unsigned char *) &y;
+ for (x = 0; x < 1; ++x)
+ b = 0;
+ for (y = 0; y < 3; ++y)
+ {
+ y = !!y;
+ if (y != 0)
+ x = y;
+ }
+ if ((b != 0 ? -1 : *a) < (y = b))
+ b = 1;
+ }
+}
Jakub