public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug tree-optimization/100113] New: missed optimization for dead code elimination at -O3 (vs. -O1) @ 2021-04-16 7:28 zhendong.su at inf dot ethz.ch 2021-04-20 8:11 ` [Bug tree-optimization/100113] " rguenth at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: zhendong.su at inf dot ethz.ch @ 2021-04-16 7:28 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100113 Bug ID: 100113 Summary: missed optimization for dead code elimination at -O3 (vs. -O1) Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: zhendong.su at inf dot ethz.ch Target Milestone: --- [584] % gcctk -v Using built-in specs. COLLECT_GCC=gcctk COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-trunk/configure --disable-bootstrap --prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++ --disable-werror --enable-multilib --with-system-zlib Thread model: posix Supported LTO compression algorithms: zlib gcc version 11.0.1 20210416 (experimental) [master revision 89c863488bc:10ed13839be:76c7e7d6b003a17d183d0571bf9b34c691819d25] (GCC) [585] % [585] % gcctk -O1 -S -o O1.s small.c [586] % gcctk -O3 -S -o O3.s small.c [587] % [587] % wc O1.s O3.s 84 185 1140 O1.s 120 254 1768 O3.s 204 439 2908 total [588] % [588] % grep foo O1.s [589] % grep foo O3.s call foo [590] % [590] % cat small.c extern void foo(void); int a, b, d, *c = &a, e, k; static int f(int *h, int i, int **l) { for (b = 0; b < 1; b++) { int *f = &d; for (; d < 1; d++) f = c; if (f != &a) __builtin_abort(); if (k) *c = 0; } *c = 0; return **l; } int main() { int *j = &b; if (!f(j, e, &j)) foo(); return 0; } ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/100113] missed optimization for dead code elimination at -O3 (vs. -O1) 2021-04-16 7:28 [Bug tree-optimization/100113] New: missed optimization for dead code elimination at -O3 (vs. -O1) zhendong.su at inf dot ethz.ch @ 2021-04-20 8:11 ` rguenth at gcc dot gnu.org 2023-08-18 2:18 ` pinskia at gcc dot gnu.org 2023-08-18 2:26 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-04-20 8:11 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100113 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2021-04-20 Ever confirmed|0 |1 Version|unknown |11.0 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- dom3 manages to optimize it with -O1 but it gets different input with -O3. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/100113] missed optimization for dead code elimination at -O3 (vs. -O1) 2021-04-16 7:28 [Bug tree-optimization/100113] New: missed optimization for dead code elimination at -O3 (vs. -O1) zhendong.su at inf dot ethz.ch 2021-04-20 8:11 ` [Bug tree-optimization/100113] " rguenth at gcc dot gnu.org @ 2023-08-18 2:18 ` pinskia at gcc dot gnu.org 2023-08-18 2:26 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-08-18 2:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100113 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |needs-bisection Known to fail| |12.2.0 Known to work| |12.3.0, 13.1.0 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Looks to be fixed in GCC 12.3.0 and GCC 13.1.0 . ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/100113] missed optimization for dead code elimination at -O3 (vs. -O1) 2021-04-16 7:28 [Bug tree-optimization/100113] New: missed optimization for dead code elimination at -O3 (vs. -O1) zhendong.su at inf dot ethz.ch 2021-04-20 8:11 ` [Bug tree-optimization/100113] " rguenth at gcc dot gnu.org 2023-08-18 2:18 ` pinskia at gcc dot gnu.org @ 2023-08-18 2:26 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-08-18 2:26 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100113 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=106922 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #2) > Looks to be fixed in GCC 12.3.0 and GCC 13.1.0 . A change in PRE which causes the IR to be different and allowed to be optimized away in DOM3 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-08-18 2:26 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-04-16 7:28 [Bug tree-optimization/100113] New: missed optimization for dead code elimination at -O3 (vs. -O1) zhendong.su at inf dot ethz.ch 2021-04-20 8:11 ` [Bug tree-optimization/100113] " rguenth at gcc dot gnu.org 2023-08-18 2:18 ` pinskia at gcc dot gnu.org 2023-08-18 2:26 ` pinskia at gcc dot gnu.org
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).