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ORDERED_EXPR in invert_tree_comparison
- From: Marc Glisse <marc dot glisse at inria dot fr>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 19 Jul 2012 17:52:02 +0200 (CEST)
- Subject: ORDERED_EXPR in invert_tree_comparison
Hello,
the simple patch below passes the testsuite after a c,c++ bootstrap
without new regressions. Note however that
#include <math.h>
int f(double a, double b){
return (!isunordered(a,b))&&(a<b);
}
is then optimized by ifcombine to "return (a<b);", which seems wrong in
the absence of -fno-trapping-math. I don't know if there are ways to
trigger this latent bug without the patch.
2012-06-15 Marc Glisse <marc.glisse@inria.fr>
PR tree-optimization/53805
* fold-const.c (invert_tree_comparison): Do invert ORDERED_EXPR and
UNORDERED_EXPR for floating point.
--- fold-const.c (revision 189622)
+++ fold-const.c (working copy)
@@ -2096,13 +2096,14 @@ pedantic_non_lvalue_loc (location_t loc,
It is generally not safe to do this for floating-point comparisons, except
for EQ_EXPR and NE_EXPR, so we return ERROR_MARK in this case. */
enum tree_code
invert_tree_comparison (enum tree_code code, bool honor_nans)
{
- if (honor_nans && flag_trapping_math && code != EQ_EXPR && code != NE_EXPR)
+ if (honor_nans && flag_trapping_math && code != EQ_EXPR && code != NE_EXPR
+ && code != ORDERED_EXPR && code != UNORDERED_EXPR)
return ERROR_MARK;
switch (code)
{
case EQ_EXPR:
return NE_EXPR;
--
Marc Glisse