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* [Bug tree-optimization/101116] New: missed peephole optimization not of bitwise and
@ 2021-06-18 5:17 hiraditya at msn dot com
2021-06-18 5:35 ` [Bug target/101116] " pinskia at gcc dot gnu.org
2021-06-18 5:42 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: hiraditya at msn dot com @ 2021-06-18 5:17 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101116
Bug ID: 101116
Summary: missed peephole optimization not of bitwise and
Product: gcc
Version: 11.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: hiraditya at msn dot com
Target Milestone: ---
$ cat test.c
bool foo(unsigned i) {
return !(i & 1);
}
gcc -O2 test.c -S -o-
foo(unsigned int):
mov eax, edi
not eax
and eax, 1
ret
clang -O2 test.c -S -o-
foo(unsigned int): # @foo(unsigned int)
testb $1, %dil
sete %al
retq
Ref: https://godbolt.org/z/Tndb1dM8Y
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/101116] missed peephole optimization not of bitwise and
2021-06-18 5:17 [Bug tree-optimization/101116] New: missed peephole optimization not of bitwise and hiraditya at msn dot com
@ 2021-06-18 5:35 ` pinskia at gcc dot gnu.org
2021-06-18 5:42 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-06-18 5:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101116
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|tree-optimization |target
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
It is an open question which is better.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/101116] missed peephole optimization not of bitwise and
2021-06-18 5:17 [Bug tree-optimization/101116] New: missed peephole optimization not of bitwise and hiraditya at msn dot com
2021-06-18 5:35 ` [Bug target/101116] " pinskia at gcc dot gnu.org
@ 2021-06-18 5:42 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-06-18 5:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101116
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Take:
unsigned char foo(unsigned *i) {
return !(*i & 1);
}
GCC and clang/LLVM produce similar code. In fact similar to what GCC produces
before.
Note also ICC produces the same code as GCC for original case. So does
Microsoft compiler. So I think we can say this is not a missed optimization
for GCC.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-06-18 5:42 UTC | newest]
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2021-06-18 5:17 [Bug tree-optimization/101116] New: missed peephole optimization not of bitwise and hiraditya at msn dot com
2021-06-18 5:35 ` [Bug target/101116] " pinskia at gcc dot gnu.org
2021-06-18 5:42 ` pinskia at gcc dot gnu.org
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