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* [Bug d/101691] New: d: Use of LOOP_EXPR prevents removing no-op loops.
@ 2021-07-30 10:35 ibuclaw at gdcproject dot org
2021-07-30 20:47 ` [Bug d/101691] " pinskia at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: ibuclaw at gdcproject dot org @ 2021-07-30 10:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101691
Bug ID: 101691
Summary: d: Use of LOOP_EXPR prevents removing no-op loops.
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: d
Assignee: ibuclaw at gdcproject dot org
Reporter: ibuclaw at gdcproject dot org
Target Milestone: ---
As observed on compiler explorer.
https://d.godbolt.org/z/eM8Pv91eT
The C, C++ (and Fortran?) front-ends lower loops as labels and gotos, which
*is* optimized away.
https://godbolt.org/z/8Yz9oqx63
---
void fun(int a, int b, int step)
{
for (int i = a; i < b; i += step) {
}
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug d/101691] d: Use of LOOP_EXPR prevents removing no-op loops.
2021-07-30 10:35 [Bug d/101691] New: d: Use of LOOP_EXPR prevents removing no-op loops ibuclaw at gdcproject dot org
@ 2021-07-30 20:47 ` pinskia at gcc dot gnu.org
2021-07-30 20:49 ` pinskia at gcc dot gnu.org
2022-07-08 8:54 ` ibuclaw at gdcproject dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-30 20:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101691
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
cannot prove finiteness of loop 1
Note the C code you posted is not the same as the D code.
Using int is able to optimize away for C++ code but not for C code.
The reason why it is able to optimize away for C++ code is because
-ffinite-loops is turned on there.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug d/101691] d: Use of LOOP_EXPR prevents removing no-op loops.
2021-07-30 10:35 [Bug d/101691] New: d: Use of LOOP_EXPR prevents removing no-op loops ibuclaw at gdcproject dot org
2021-07-30 20:47 ` [Bug d/101691] " pinskia at gcc dot gnu.org
@ 2021-07-30 20:49 ` pinskia at gcc dot gnu.org
2022-07-08 8:54 ` ibuclaw at gdcproject dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-30 20:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101691
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
LOOP_EXPR has nothing to do with this problem really.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug d/101691] d: Use of LOOP_EXPR prevents removing no-op loops.
2021-07-30 10:35 [Bug d/101691] New: d: Use of LOOP_EXPR prevents removing no-op loops ibuclaw at gdcproject dot org
2021-07-30 20:47 ` [Bug d/101691] " pinskia at gcc dot gnu.org
2021-07-30 20:49 ` pinskia at gcc dot gnu.org
@ 2022-07-08 8:54 ` ibuclaw at gdcproject dot org
2 siblings, 0 replies; 4+ messages in thread
From: ibuclaw at gdcproject dot org @ 2022-07-08 8:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101691
Iain Buclaw <ibuclaw at gdcproject dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|UNCONFIRMED |RESOLVED
--- Comment #3 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
Confirmed it is finite loops that makes the difference, nothing to do here.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-07-08 8:54 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-07-30 10:35 [Bug d/101691] New: d: Use of LOOP_EXPR prevents removing no-op loops ibuclaw at gdcproject dot org
2021-07-30 20:47 ` [Bug d/101691] " pinskia at gcc dot gnu.org
2021-07-30 20:49 ` pinskia at gcc dot gnu.org
2022-07-08 8:54 ` ibuclaw at gdcproject dot org
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