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From: "shaohua.li at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/109925] New: Wrong code at -O2 on x86_64-linux-gnu since GCC-12 Date: Sun, 21 May 2023 15:02:02 +0000 [thread overview] Message-ID: <bug-109925-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109925 Bug ID: 109925 Summary: Wrong code at -O2 on x86_64-linux-gnu since GCC-12 Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: shaohua.li at inf dot ethz.ch Target Milestone: --- For the following code, gcc trunk emits wrong code at -O2. Compiler explorer: https://godbolt.org/z/hcnaxoPaP $ cat a.c int printf(const char *, ...); int a, c, f; int main() { int g[2]; c = 0; for (; c < 2; c++) { { char h[20]; char *b = h; int d = 48, e = 0; while (d && e < 5) b[e++] = d /= 10; f = e; } g[f - 2 + c] = 0; } for (;;) { for (; a <= 4; a++) if (g[0]) break; break; } printf("%d\n", a); } $ $ gcc-tk -O0 a.c && ./a.out 5 $ gcc-tk -O2 a.c && ./a.out 0 $ gcc-tk -v Using built-in specs. COLLECT_GCC=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-f211757f6fa9515e3fd1a4f66f1a8b48e500c9de/bin/gcc COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-f211757f6fa9515e3fd1a4f66f1a8b48e500c9de/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../configure --disable-multilib --disable-bootstrap --enable-languages=c,c++ --prefix=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-f211757f6fa9515e3fd1a4f66f1a8b48e500c9de Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 20230521 (experimental) (GCC) $
next reply other threads:[~2023-05-21 15:02 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-05-21 15:02 shaohua.li at inf dot ethz.ch [this message] 2023-05-21 15:17 ` [Bug tree-optimization/109925] [10/11/12/13/14 Regression] " jakub at gcc dot gnu.org 2023-05-26 6:33 ` rguenth at gcc dot gnu.org 2023-07-07 10:45 ` [Bug tree-optimization/109925] [11/12/13/14 " rguenth at gcc dot gnu.org 2024-01-12 13:32 ` rguenth at gcc dot gnu.org 2024-03-27 16:50 ` jakub at gcc dot gnu.org 2024-03-28 11:00 ` cvs-commit at gcc dot gnu.org 2024-03-28 11:01 ` jakub at gcc dot gnu.org 2024-03-30 3:55 ` cvs-commit at gcc dot gnu.org
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