https://gcc.gnu.org/g:c53bd48c6920bc1f4039b6682aafbf414a600e47
commit r15-4313-gc53bd48c6920bc1f4039b6682aafbf414a600e47
Author: Richard Biener <rguent...@suse.de>
Date: Mon Oct 14 08:11:22 2024 +0200
middle-end/116891 - fix (negate (IFN_FNMS@3 @0 @1 @2)) -> (IFN_FMA @0 @1 @2)
Transforming -fma (-a, b, -c) to fma (a, b, c) is only valid when
not rounding towards -inf or +inf as the sign of the multiplication
changes.
PR middle-end/116891
* match.pd ((negate (IFN_FNMS@3 @0 @1 @2)) -> (IFN_FMA @0 @1 @2)):
Only enable for !HONOR_SIGN_DEPENDENT_ROUNDING.
Diff:
---
gcc/match.pd | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/match.pd b/gcc/match.pd
index 2814618124d7..ee53c25cef97 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -9494,7 +9494,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(IFN_FMA @0 @1 @2))
(simplify
(negate (IFN_FNMS@3 @0 @1 @2))
- (if (single_use (@3))
+ (if (!HONOR_SIGN_DEPENDENT_ROUNDING (type) && single_use (@3))
(IFN_FMA @0 @1 @2))))
/* CLZ simplifications. */
