https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50918
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Since GCC 9 for test_cst, the following is produced:
movdqa a(%rip), %xmm0
psllw $3, %xmm0
movaps %xmm0, r(%rip)
ret
For test_var, GCC produces the following on the trunk:
test_var:
movdqa a(%rip), %xmm0
movslq %edi, %rax
movq %rax, %xmm2
pmovsxwd %xmm0, %xmm1
psrldq $8, %xmm0
pmovsxwd %xmm0, %xmm0
pslld %xmm2, %xmm1
pslld %xmm2, %xmm0
movdqa .LC0(%rip), %xmm2
pand %xmm2, %xmm1
pand %xmm0, %xmm2
movdqa %xmm1, %xmm0
packusdw %xmm2, %xmm0
movaps %xmm0, r(%rip)
ret
