https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106609
Sébastien Michelland <sebastien.michell...@ens-lyon.fr> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[SH] miscompilation of loop |[SH] miscompilation due to
|involving noreturn call |incorrect elimination of
| |comparisons to 0
--- Comment #4 from Sébastien Michelland <sebastien.michell...@ens-lyon.fr> ---
> Then this is a target specific issue until provided otherwise. mach stands
> for machine (target) specific pass.
That makes a lot of sense, thanks.
I found a much simpler example exhibiting the bug:
int f(int i, int j)
{
if(i < 0) return 1;
if(i + j) return 3;
return i;
}
Latest HEAD with -O1 (same setup as before) compiles it to
_f: cmp/pz r4
bf .L3
bf .L4
rts
mov r4,r0
.L3: rts
mov #1,r0
.L4: rts
mov #3,r0
incorrectly eliminating the test for (i + j) != 0. The label .L4 returning 3 is
evidently unreachable.
Comparing to 0 seems to be required. My previous example also compiles
correctly if we check values[i] != 1 instead, which invalidates the loop/CFG
theory.
Few commits changed the SH subtree since GCC 11.1.0; I should be able to bisect
it. In the meantime I've updated the title.
