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From: "aoliva at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug debug/106746] [13 Regression] '-fcompare-debug' failure
 (length) with -O2 -fsched2-use-superblocks since r13-2041-g6624ad73064de241
Date: Sat, 14 Jan 2023 08:29:38 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106746

--- Comment #17 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Created attachment 54272
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D54272&action=3Dedit
patch that fixes the problem for reasons not fully understood

It seems that looking up the MEM exprs in DEBUG_INSNs disturbs something in
cselib and causes pending MEMs to conflict that, in the non-debug case, don=
't.

There's no need for these lookups in debug insns, the results aren't used, =
and
I thought I'd just queue up this improvement but, to my surprise, it made t=
he
problem go away.=