https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99862
Bug ID: 99862 Summary: [meta-issue] various missed optimizations for dead code elimination Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: ipa Assignee: unassigned at gcc dot gnu.org Reporter: zhendong.su at inf dot ethz.ch CC: marxin at gcc dot gnu.org Target Milestone: --- [561] % 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 20210401 (experimental) [master revision e4bb1bd60a9:c23a685bf70:95d217ab52d31dc06fda42fc136dea165909e88b] (GCC) [562] % [562] % gcctk -O1 -S -o O1.s small.c [563] % gcctk -O3 -S -o O3.s small.c [564] % [564] % wc O1.s O3.s 23 45 420 O1.s 39 74 669 O3.s 62 119 1089 total [565] % [565] % grep foo O1.s [566] % grep foo O3.s call foo [567] % [567] % cat small.c extern void foo(void); static int a, b; static int c() { foo(); while (1) while (b) foo(); } void d() { if (a) c(); } int main() { d(); return 0; }