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Subject: [Bug debug/99830] [11 Regression] ICE: in lra_eliminate_regs_1, at
 lra-eliminations.c:659 with -O2 -fno-expensive-optimizations
 -fno-split-wide-types -g
Date: Fri, 09 Apr 2021 12:29:58 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99830

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #3)
> In normal insns such clobbers would be rejected by recog, but for
> DEBUG_INSNs we don't have strict validity tests, but guess we need to thr=
ow
> away at least the worst garbage.

combine puts clobbers of const0_rtx in instructions precisely because
those *should* be rejected; it does it to abort a combination attempt.
So it isn't clear to me why we end up with this here?  Papering over it
(as the proposed patch does) is not a good idea imho.=