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* [Bug target/87601] Missed opportunity for flag reuse and macro-op fusion on x86
[not found] <bug-87601-4@http.gcc.gnu.org/bugzilla/>
@ 2021-12-21 11:08 ` pinskia at gcc dot gnu.org
2021-12-21 11:09 ` [Bug tree-optimization/87601] " pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-21 11:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87601
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
sub rsi, 1
test esi, esi
jne .L3
To
sub rsi, 1
jne .L3
Is not the same, the first is a 64bit subtract followed by a 32bit compare. in
the 2nd case, you have a 64bit subtract with the 64bit compare happening.
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug tree-optimization/87601] Missed opportunity for flag reuse and macro-op fusion on x86
[not found] <bug-87601-4@http.gcc.gnu.org/bugzilla/>
2021-12-21 11:08 ` [Bug target/87601] Missed opportunity for flag reuse and macro-op fusion on x86 pinskia at gcc dot gnu.org
@ 2021-12-21 11:09 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-21 11:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87601
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-12-21
Status|UNCONFIRMED |NEW
Component|target |tree-optimization
Severity|normal |enhancement
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
But IV-OPTs could have changed:
i_19 = (int) ivtmp.8_22;
if (i_19 != 0)
goto <bb 4>; [89.00%]
else
goto <bb 5>; [11.00%]
Into:
if (ivtmp.8_22 != 0)
goto <bb 4>; [89.00%]
else
goto <bb 5>; [11.00%]
Which would have done the correct thing.
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2021-12-21 11:09 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <bug-87601-4@http.gcc.gnu.org/bugzilla/>
2021-12-21 11:08 ` [Bug target/87601] Missed opportunity for flag reuse and macro-op fusion on x86 pinskia at gcc dot gnu.org
2021-12-21 11:09 ` [Bug tree-optimization/87601] " pinskia at gcc dot gnu.org
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