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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug rtl-optimization/101995] [9/10/11/12 Regression] regression
 built-in memset missed-optimization arm -Os since r9-3594
Date: Thu, 09 Dec 2021 08:18:35 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101995

--- Comment #10 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>I don't see any problem with aarch64 fwiw.
I have to try it on aarch64 but it failed there at one point.

(In reply to Segher Boessenkool from comment #8)
> Also, what is fragile here?  This is *removing* fragility and premature
> choices!

(In reply to Segher Boessenkool from comment #9)
> (In reply to Segher Boessenkool from comment #7)
> > What is this REG_RETURNED thing?
>=20
> Ah, something added in ira-lives.c, and you call *that* code fragile?
> I agree :-)

You got to what I thought was fragile in the end. And yes the whole
REG_RETURNED mechanism seems very fragile (not the change r9-3594 ). I could
not figure out how it was being known to be set on which function call even=
.=