https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115034
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Keywords| |missed-optimization
Last reconfirmed| |2024-05-13
Ever confirmed|0 |1
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
This would work if we'd duplicate the path from a = 0 to *outl = 1; return 0;
but we don't early enough (on GIMPLE) and we don't do that on RTL until
BB reorder where ther's no later pass doing this optimization either.
On GIMPLE we see
<bb 2> [local count: 1073741824]:
*outl_4(D) = 0;
if (c1_6(D) != 0)
goto <bb 3>; [50.00%]
else
goto <bb 5>; [50.00%]
...
<bb 5> [local count: 965079152]:
# a_1 = PHI <1(3), 0(2)>
*outl_4(D) = a_1;
return 0;
but I think tracer doesn't consider paths to exit aka tail duplication,
likely because on GIMPLE we force a single return block. There's also
no partial redundant store elimination.
