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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) -- links below jump to the message on this page -- 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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