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From: "acoplan at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/113089] [14 Regression][aarch64] ICE in
 process_uses_of_deleted_def, at rtl-ssa/changes.cc:252 since
 r14-6605-gc0911c6b357ba9
Date: Wed, 20 Dec 2023 11:05:20 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113089

--- Comment #9 from Alex Coplan <acoplan at gcc dot gnu.org> ---
(In reply to Manolis Tsamis from comment #8)
> (In reply to Alex Coplan from comment #7)
> > (In reply to Manolis Tsamis from comment #6)
> > > (In reply to Alex Coplan from comment #5)
> > > > Also ICEs without -fno-strict-aliasing FWIW, so just -g -O2 -funrol=
l-loops
> > > > seems to be enough.
> > >=20
> > > On my local build it doesn't reproduce without -fno-strict-aliasing; =
I just
> > > double-checked (GCC master @ 4e0a467302fea56d63b7a6d17f99c0f388960dc7=
).
> >=20
> > Hmm, that is odd, I definitely don't need that option even when built f=
rom
> > the same commit.  How are you configuring GCC?  I suppose it doesn't ma=
tter
> > since I can reproduce the problem as long as the fix works with/without
> > -fno-strict-aliasing.
>=20
> Odd indeed, but probably something with my configure flags as you mention=
ed.
> Here's what I use:
>=20
>         --enable-shared \
>         --enable-threads=3Dposix \
>         --enable-checking=3Drelease \
>         --with-system-zlib \
>         --enable-__cxa_atexit \
>         --disable-libunwind-exceptions \
>         --enable-linker-build-id \
>         --enable-libstdcxx-backtrace \
>         --enable-plugin \
>         --enable-initfini-array \
>         --enable-gnu-indirect-function \
>         --with-isl \
>         --enable-lto \
>         --with-cpu=3Dneoverse-n1 \
>         --disable-multilib \
>         --disable-bootstrap
>=20
> (I think the most uncommon one here is --with-cpu=3Dneoverse-n1 ?)

Ah, that explains it.  I have a much more vanilla config, and indeed with
-mcpu=3Dneoverse-n1 then it needs -fno-strict-aliasing to reproduce.=