https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97891
--- Comment #6 from Hongtao.liu ---
cat test.c
typedef struct {
long a;
long b;
}TI;
extern TI r;
void
foo ()
{
r.a = 0;
r.b = 0;
}
gcc -Ofast -march=cascadelake -S got
foo:
.LFB0:
.cfi_startproc
movq$0, r(%rip)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97891
--- Comment #5 from andysem at mail dot ru ---
Using a register is beneficial even for bytes and words if there are multiple
of mov instructions. But there has to be a single reg0 for all movs.
I'm not very knowlegeable about gcc internals, but w
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97891
--- Comment #4 from Hongtao.liu ---
(In reply to Hongtao.liu from comment #3)
> This problem is very similar to the one pass_rpad deals with.
We already have mov_xor for mov $0 to reg, so we only need to handle mov
$0 to mem.
and size for:
xor
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97891
--- Comment #3 from Hongtao.liu ---
This problem is very similar to the one pass_rpad deals with.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97891
Richard Biener changed:
What|Removed |Added
Last reconfirmed||2020-11-18
Status|UNCONFIRM
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97891
--- Comment #1 from andysem at mail dot ru ---
As a side note, the "xorl %edx, %edx" in the original code should have been
moved outside the loop, as it was in the code with __asm__ block.
