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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109154] [13 regression] jump threading
 de-optimizes nested floating point comparisons
Date: Mon, 27 Mar 2023 10:59:54 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109154

--- Comment #20 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #18)
> Hmm, I guess if users enable FTZ we could instruct them to tell that to
> the compiler, but requiring -funsafe-math-optimizations is quite a
> difficult suggestion here.  Maybe we can add a special -fftz flag for

I think people rarely enable FTZ by hand, they enable it by linking in
crtfastmath
through linking with -Ofast/-ffast-math/-funsafe-math-optimizations.
And, enabling FTZ is such an unsafe math optimization already, it violates =
IEEE
754
to gain some extra performance.=