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* [gcc r12-4985] Add !HONOR_SNANS to simplifcation: (trunc)copysign((extend)a, (extend)b) to copysign (a, b).
@ 2021-11-08 1:38 hongtao Liu
0 siblings, 0 replies; only message in thread
From: hongtao Liu @ 2021-11-08 1:38 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:a1f7ead09cd41d32e2feffff902eb32e587c36e7
commit r12-4985-ga1f7ead09cd41d32e2feffff902eb32e587c36e7
Author: liuhongt <hongtao.liu@intel.com>
Date: Mon Nov 8 09:32:17 2021 +0800
Add !HONOR_SNANS to simplifcation: (trunc)copysign((extend)a, (extend)b) to copysign (a, b).
> Note that this is not safe with -fsignaling-nans, so needs to be disabled
> for that option (if there isn't already logic somewhere with that effect),
> because the extend will convert a signaling NaN to quiet (raising
> "invalid"), but copysign won't, so this transformation could result in a
> signaling NaN being wrongly returned when the original code would never
> have returned a signaling NaN.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com
gcc/ChangeLog
PR target/102464
* match.pd (Simplifcation (trunc)copysign((extend)a, (extend)b)
to .COPYSIGN (a, b)): Add !HONOR_SNANS.
Diff:
---
gcc/match.pd | 1 +
1 file changed, 1 insertion(+)
diff --git a/gcc/match.pd b/gcc/match.pd
index 869b26d16a0..71cf6f9df0a 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6210,6 +6210,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(simplify
(convert (copysigns (convert@2 @0) (convert @1)))
(if (optimize
+ && !HONOR_SNANS (@2)
&& types_match (type, TREE_TYPE (@0))
&& types_match (type, TREE_TYPE (@1))
&& TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@2))
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2021-11-08 1:38 [gcc r12-4985] Add !HONOR_SNANS to simplifcation: (trunc)copysign((extend)a, (extend)b) to copysign (a, b) hongtao Liu
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