public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "zhendong.su at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/100314] New: missed optimization for dead code elimination at -O3 (vs. -O1) Date: Wed, 28 Apr 2021 10:17:26 +0000 [thread overview] Message-ID: <bug-100314-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100314 Bug ID: 100314 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: --- [592] % 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/12.0.0/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 12.0.0 20210428 (experimental) [master revision 852dd866e2f:9b04e5b2651:b81e2d5e76a6bcc71f45b122e8b5538ddb7ebf4c] (GCC) [593] % [593] % gcctk -O1 -S -o O1.s small.c [594] % gcctk -O3 -S -o O3.s small.c [595] % [595] % wc O1.s O3.s 21 45 392 O1.s 42 86 686 O3.s 63 131 1078 total [596] % [596] % grep foo O1.s [597] % grep foo O3.s jmp foo [598] % [598] % cat small.c extern void foo(void); static int a, *c, g, **j; int b; static void e() { int k, *l[5] = {&k, &k, &k, &k, &k}; while (g) { j = &l[0]; b++; } } static void d(int m) { int **h[30] = {&c}, ***i[1] = {&h[3]}; if (m) foo(); e(); } int main() { d(a); return 0; }
next reply other threads:[~2021-04-28 10:17 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-28 10:17 zhendong.su at inf dot ethz.ch [this message] 2021-09-25 10:05 ` [Bug ipa/100314] missed optimization for dead code elimination at -O3 (vs. -O1) (inlining differences) pinskia at gcc dot gnu.org 2022-01-11 9:53 ` rguenth at gcc dot gnu.org 2022-01-11 10:36 ` hubicka at gcc dot gnu.org 2022-01-11 10:40 ` hubicka at gcc dot gnu.org 2023-08-18 2:32 ` [Bug ipa/100314] missed optimization for dead code elimination at -O3 (vs. -O1) (inlining differences due to missed dse) pinskia at gcc dot gnu.org 2024-05-15 16:44 ` rguenth at gcc dot gnu.org 2024-05-16 9:04 ` cvs-commit at gcc dot gnu.org 2024-05-16 9:05 ` rguenth at gcc dot gnu.org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-100314-4@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
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).