From: Jeff Law <law@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [committed] cselib: Fix endless cselib loop on (plus:P (reg) (const_int 0))
Date: Mon, 06 Apr 2020 16:57:46 -0600 [thread overview]
Message-ID: <ec6c95cb6e73d355c369048fed2d65e6ab29e924.camel@redhat.com> (raw)
In-Reply-To: <20200406223313.GV2212@tucnak>
On Tue, 2020-04-07 at 00:33 +0200, Jakub Jelinek wrote:
> Hi!
>
> getopt.c hangs the compiler on h8300-elf with -O2 -g, because the
> IL contains addition of constant 0, the first PLUS operand is determined
> to have the SP_DERIVED_VALUE_P and the new code in cselib recurses
> indefinitely on seeing SP_DERIVED_VALUE_P with locs of
> (plus:P SP_DERIVED_VALUE_P (const_int 0)).
>
> Fixed by making sure cselib_subst_to_values canonicalizes it, hashing
> already hashes it the same too.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, tested on the
> getopt.i testcase using cross to h8300-elf, approved off-list by Jeff,
> committed to trunk.
>
> 2020-04-06 Jakub Jelinek <jakub@redhat.com>
>
> * cselib.c (cselib_subst_to_values): For SP_DERIVED_VALUE_P
> + const0_rtx return the SP_DERIVED_VALUE_P.
Thanks. And just FTR, the scenario where this happens could (in theory) happen
on other ports, particularly those still using reload.
jeff
>
next prev parent reply other threads:[~2020-04-06 22:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-06 22:33 Jakub Jelinek
2020-04-06 22:57 ` Jeff Law [this message]
2020-04-07 22:35 ` Joseph Myers
2020-04-07 22:42 ` Jeff Law
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