http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48607
Summary: Inefficient complex float parameter passing
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: hjl.to...@gmail.com
CC: ubiz...@gmail.com
[hjl@gnu-6 pr1000]$ cat z.i
typedef _Complex float SCtype;
SCtype
foo (SCtype x1, SCtype x2, SCtype x3, SCtype x4, SCtype x5, SCtype x6,
SCtype x7, SCtype x8, SCtype a, SCtype b)
{
return x2;
}
[hjl@gnu-6 pr1000]$ /usr/gcc-4.7/bin/gcc -O2 -S z.i
[hjl@gnu-6 pr1000]$ cat z.s
.file "z.i"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
movq %xmm1, -16(%rsp)
movl -16(%rsp), %eax
movl %eax, -72(%rsp)
movl -12(%rsp), %eax
movl %eax, -68(%rsp)
movq -72(%rsp), %xmm0
ret
.cfi_endproc
.LFE0:
.size foo, .-foo
.ident "GCC: (GNU) 4.7.0 20110406 (experimental) [trunk revision
172062]"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-6 pr1000]$
We should simply do
movaps %xmm1, %xmm0
or
movq %xmm1,%xmm0
