http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43653
--- Comment #16 from Uros Bizjak <ubizjak at gmail dot com> 2011-02-17 21:05:11
UTC ---
The assembly from -O1 -ftree-vectorize -msse3 shows another opportunity for
enhancement PR19398 (secondary reloads don't consider "m" alternatives):
.LFB0:
.cfi_startproc
subq $416, %rsp
.cfi_def_cfa_offset 424
movq .LC1(%rip), %rax
leaq (%rsp,%rax), %rax
movq %rax, -112(%rsp)
(*) movq -112(%rsp), %xmm1
(*) punpcklqdq %xmm1, %xmm1
movdqa %xmm1, %xmm0
leaq -104(%rsp), %rax
leaq 408(%rsp), %rdx
.L2:
Looking at the definition of
(define_insn "*vec_dupv2di_sse3"
[(set (match_operand:V2DI 0 "register_operand" "=x,x")
(vec_duplicate:V2DI
(match_operand:DI 1 "nonimmediate_operand" " 0,m")))]
"TARGET_SSE3"
"@
punpcklqdq\t%0, %0
movddup\t{%1, %0|%0, %1}"
[(set_attr "type" "sselog1")
(set_attr "mode" "TI,DF")])
the two insns marked with (*) can be substituted with the second alternative:
movddup -112(%rsp), %xmm1.
