https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82636
Bug ID: 82636
Summary: powerpc: Unnecessary copy of __ieee128 parameter
Product: gcc
Version: 7.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: tuliom at linux dot vnet.ibm.com
Target Milestone: ---
Tested with GCC 7.2.1 on powerpc64le.
The copy of vs36 (v4) to vs32 (v0) shouldn't be required, i.e. I'd expect to
have xsmaddqp v4,v2,v3.
$ cat s_fmaf128-power9.c
__ieee128
__fmaf128_power9 (__ieee128 x, __ieee128 y, __ieee128 z)
{
asm ("xsmaddqp\t%0, %1, %2" : "+v" (z) : "v" (x), "v" (y));
return z;
}
$ gcc -mcpu=power9 -mfloat128 -O3 -c s_fmaf128-power9.c -o test.o
$ objdump -d test.o
...
0000000000000000 <__fmaf128_power9>:
0: 97 24 04 f0 xxlor vs32,vs36,vs36 <----
4: 08 1b 02 fc xsmaddqp v0,v2,v3
8: 97 04 40 f0 xxlor vs34,vs32,vs32
c: 20 00 80 4e blr
...
