[Bug target/80833] 32-bit x86 causes store-forwarding stalls for int64_t -> xmm

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80833

--- Comment #8 from Uroš Bizjak <ubizjak at gmail dot com> ---
The patch from comment #7 generates:

a) DImode move for 32 bit targets:

--cut here--
long long test (long long a)
{
  asm ("" : "+x" (a));
  return a;
}
--cut here--

gcc -O2 -msse4.1 -mtune=intel -mregparm=2:

        movd    %eax, %xmm0
        pinsrd  $1, %edx, %xmm0
        movq    %xmm0, (%esp)       <<-- unneeded store due to RA problem
        movd    %xmm0, %eax
        pextrd  $1, %xmm0, %edx
        leal    12(%esp), %esp

b) TImode move for 64 bit targets:

--cut here--
__int128 test (__int128 a)
{
  asm ("" : "+x" (a));
  return a;
}
--cut here--

gcc -O2 -msse4.1 -mtune=intel

        movq    %rdi, %xmm0
        pinsrq  $1, %rsi, %xmm0
        pextrq  $1, %xmm0, %rdx
        movq    %xmm0, %rax