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[PATCH] Fix PR63665
- From: Richard Biener <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 28 Oct 2014 12:35:29 +0100 (CET)
- Subject: [PATCH] Fix PR63665
- Authentication-results: sourceware.org; auth=none
The following fixes folding of x + CST != CST with -fwrapv. Even
with -fwrapv overflow is signalled by int_const_binop with
TREE_OVERFLOW but of course we cannot do any undefined overflow
optimizations when overflow wraps.
bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2014-10-28 Richard Biener <rguenther@suse.de>
PR middle-end/63665
* fold-const.c (fold_comparison): Properly guard simplifying
against INT_MAX/INT_MIN with !TYPE_OVERFLOW_WRAPS.
* gcc.dg/pr63665.c: New testcase.
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 216771)
+++ gcc/fold-const.c (working copy)
@@ -8751,7 +8770,8 @@ fold_comparison (location_t loc, enum tr
/* If the constant operation overflowed this can be
simplified as a comparison against INT_MAX/INT_MIN. */
- if (TREE_OVERFLOW (new_const))
+ if (TREE_OVERFLOW (new_const)
+ && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0)))
{
int const1_sgn = tree_int_cst_sgn (const1);
enum tree_code code2 = code;
Index: gcc/testsuite/gcc.dg/pr63665.c
===================================================================
--- gcc/testsuite/gcc.dg/pr63665.c (revision 0)
+++ gcc/testsuite/gcc.dg/pr63665.c (working copy)
@@ -0,0 +1,18 @@
+/* { dg-do run } */
+/* { dg-require-effective-target int32plus } */
+/* { dg-options "-O -fno-tree-ccp -fno-tree-fre -fno-tree-copy-prop -fwrapv" } */
+
+static inline int
+test5 (int x)
+{
+ int y = 0x80000000;
+ return x + y;
+}
+
+int
+main ()
+{
+ if (test5 (0x80000000) != 0)
+ __builtin_abort ();
+ return 0;
+}