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* [Bug tree-optimization/97529] New: Condition not constant folded
@ 2020-10-22 14:51 jmuizelaar at mozilla dot com
2021-07-23 3:38 ` [Bug tree-optimization/97529] " pinskia at gcc dot gnu.org
2023-02-10 22:30 ` [Bug tree-optimization/97529] (len / N) * N <= len is not optimized to 1 pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: jmuizelaar at mozilla dot com @ 2020-10-22 14:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97529
Bug ID: 97529
Summary: Condition not constant folded
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jmuizelaar at mozilla dot com
Target Milestone: ---
>From https://github.com/rust-lang/rust/issues/74938
GCC compiles:
#include <stddef.h>
const size_t N = 3;
int foo(size_t len) {
size_t newlen = (len / N) * N;
return newlen <= len;
}
to:
foo:
movabs rdx, -6148914691236517205
mov rax, rdi
mul rdx
mov rax, rdx
and rdx, -2
shr rax
add rdx, rax
xor eax, eax
cmp rdi, rdx
setnb al
ret
N:
.quad 3
clang:
foo: # @foo
mov eax, 1
ret
N:
.quad 3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/97529] Condition not constant folded
2020-10-22 14:51 [Bug tree-optimization/97529] New: Condition not constant folded jmuizelaar at mozilla dot com
@ 2021-07-23 3:38 ` pinskia at gcc dot gnu.org
2023-02-10 22:30 ` [Bug tree-optimization/97529] (len / N) * N <= len is not optimized to 1 pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-23 3:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97529
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-07-23
CC| |pinskia at gcc dot gnu.org
Status|UNCONFIRMED |NEW
Severity|normal |enhancement
Ever confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/97529] (len / N) * N <= len is not optimized to 1
2020-10-22 14:51 [Bug tree-optimization/97529] New: Condition not constant folded jmuizelaar at mozilla dot com
2021-07-23 3:38 ` [Bug tree-optimization/97529] " pinskia at gcc dot gnu.org
@ 2023-02-10 22:30 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-02-10 22:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97529
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |DUPLICATE
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Dup of bug 96433.
*** This bug has been marked as a duplicate of bug 96433 ***
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-02-10 22:30 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-10-22 14:51 [Bug tree-optimization/97529] New: Condition not constant folded jmuizelaar at mozilla dot com
2021-07-23 3:38 ` [Bug tree-optimization/97529] " pinskia at gcc dot gnu.org
2023-02-10 22:30 ` [Bug tree-optimization/97529] (len / N) * N <= len is not optimized to 1 pinskia at gcc dot gnu.org
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