https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81614
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |DUPLICATE
Summary|x86 optimizer combines |Should
|results of comparisons in a |-mtune-ctrl=partial_reg_sta
|way that risks partial |ll be turned by default?
|register stalls |
--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
With -mtune-ctrl=partial_reg_stall, I got
[hjl@gnu-tools-1 pr81614]$ cat x.i
_Bool
foo(int a, int b, int c)
{
return (a == c || b == c);
}
int
bar (int a, int b, int c)
{
return (a == c || b == c);
}
[hjl@gnu-tools-1 pr81614]$ make
/export/build/gnu/gcc/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2
-mtune-ctrl=partial_reg_stall -S x.i
[hjl@gnu-tools-1 pr81614]$ cat x.s
.file "x.i"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
cmpl %edx, %edi
sete %al
cmpl %esi, %edx
sete %dl
orb %dl, %al
ret
.cfi_endproc
.LFE0:
.size foo, .-foo
.p2align 4,,15
.globl bar
.type bar, @function
bar:
.LFB1:
.cfi_startproc
cmpl %edx, %edi
sete %al
cmpl %esi, %edx
sete %dl
orb %dl, %al
movzbl %al, %eax
ret
.cfi_endproc
.LFE1:
.size bar, .-bar
.ident "GCC: (GNU) 8.0.0 20170730 (experimental)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-tools-1 pr81614]$
I opened PR 81616 to update default tuning options.
*** This bug has been marked as a duplicate of bug 81616 ***
