https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99862
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Zhendong Su from comment #1)
> [578] % gcctk -O1 -S -o O1.s small.c
> [579] % gcctk -O3 -S -o O3.s small.c
> [580] %
> [580] % wc O1.s O3.s
> 22 43 410 O1.s
> 37 77 682 O3.s
> 59 120 1092 total
> [581] %
> [581] % grep foo O1.s
> [582] % grep foo O3.s
> call foo
> [583] %
> [583] % cat small.c
> extern void foo(void);
> static int a, b;
> static void c() {
> if (a) {
> foo();
> for (; b < 1; b++)
> ;
> }
> }
> int main() {
> c();
> c();
> return 0;
> }
This is another case of failing to elide a no longer called function. We
end up partially inlining c() at -O3, inlining the if (a) head and thus
we eliminate the calls to c() in main rather than the call to foo in c().
I'd say the -O3 result is superior but still we fail to remove the
c.part() function definition from the assembly. We have duplicates for this
case.
