[Bug ipa/99834] missed optimization for dead code elimination at -O3 (vs. -O2)

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99834

--- Comment #3 from Andrew Pinski  ---
The other way of optimizing this is to see that the return value of d is 0
(even early on) and do a const prop of that ... IN a sense an IPA-CCP for
return values rather than for argument passing.

[Bug ipa/99834] missed optimization for dead code elimination at -O3 (vs. -O2)

[zhendong.su at inf dot ethz.ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99834

--- Comment #2 from Zhendong Su  ---
Hi Richard and all, thanks for analyzing these reports! 

I have some more cases, and wonder whether you folks would prefer that I open a
meta issue report and append these (and others that we find) to that report
(rather than filing these one by one). Thanks.

[Bug ipa/99834] missed optimization for dead code elimination at -O3 (vs. -O2)

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99834

Richard Biener  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
   Last reconfirmed||2021-03-31
Version|unknown |11.0
 CC||hubicka at gcc dot gnu.org
   Keywords||missed-optimization
 Ever confirmed|0   |1

--- Comment #1 from Richard Biener  ---
Similar to the other bug - when 'main' is named 'bar' then we optimize it OK at
-O3, the difference being again loop header copying not applied in "cold"
context
but inlining is.

Not sure if we want to call this a bug, but then the inconsistency is odd.