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From: "tnfchris at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/113136] [14 regression] ICE when building
 Perl
Date: Wed, 27 Dec 2023 14:52:42 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113136

--- Comment #8 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
Thanks, was able to reproduce with `--enable-checking=3Dyes,rtl,extra`.

The issue seems to be that the value is unused, and we were relying on DSE
removing such statement. but with --enable-checking=3Dyes,rtl,extra the ext=
ra
verification is done before we can remove the dead statements on these inve=
rted
loops.

That's why it doesn't fail without and produces the right code.

So it looks like this is the same bug as
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113137 and the fix for that =
should
fix this.  It looks like for these inverted loops, even though none of the
values are used, I have to maintain the virtual phis.

I'll keep the two separate for now..=