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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/99862] [meta-issue] various missed optimizations for dead code elimination
Date: Fri, 09 Apr 2021 11:53:54 +0000 [thread overview]
Message-ID: <bug-99862-4-v2VqRBgGDX@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99862-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99862
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #7)
> (In reply to Zhendong Su from comment #2)
> > [659] % gcctk -O1 -S -o O1.s small.c
> > [660] % gcctk -O3 -S -o O3.s small.c
> > [661] %
> > [661] % wc O1.s O3.s
> > 40 86 599 O1.s
> > 68 138 1047 O3.s
> > 108 224 1646 total
> > [662] %
> > [662] % grep foo O1.s
> > [663] % grep foo O3.s
> > call foo
> > [664] %
> > [664] % cat small.c
> > extern void foo(void);
> > int a, b, *c;
> > static void d(int f) {
> > if (f)
> > foo();
> > }
> > static int e(int f) {
> > int g[] = {2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2};
> > int h[60];
> > h[0] = g != c;
> > if (b)
> > while (a) {
> > int *i[1] = {&h[6]};
> > }
> > return f;
> > }
> > static int *j(int *p) { return 0; }
> > int main () {
> > int m = e(0);
> > d(m);
> > int l[8];
> > if (j(l))
> > while (1)
> > ;
> > return 0;
> > }
>
> This is a case similar to PR99991, we create a IPA CP clone and fail to
> inline
> that at -O3 while we are happy to IPA inline e() at -O1.
I filed PR99993 for it.
For the future please open separate bugs for separate testcases.
next prev parent reply other threads:[~2021-04-09 11:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 7:59 [Bug ipa/99862] New: " zhendong.su at inf dot ethz.ch
2021-04-01 8:01 ` [Bug ipa/99862] " zhendong.su at inf dot ethz.ch
2021-04-01 8:06 ` zhendong.su at inf dot ethz.ch
2021-04-02 0:28 ` egallager at gcc dot gnu.org
2021-04-02 17:02 ` zhendong.su at inf dot ethz.ch
2021-04-09 11:37 ` rguenth at gcc dot gnu.org
2021-04-09 11:39 ` rguenth at gcc dot gnu.org
2021-04-09 11:42 ` rguenth at gcc dot gnu.org
2021-04-09 11:53 ` rguenth at gcc dot gnu.org [this message]
2021-04-09 11:59 ` zhendong.su at inf dot ethz.ch
2021-04-10 10:12 ` egallager at gcc dot gnu.org
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