merge consecutive stores of extracted vector elements
Add a path to DAGCombiner::MergeConsecutiveStores()
to combine multiple scalar stores when the store operands
are extracted vector elements. This is a partial fix for
PR21711 ( http://llvm.org/bugs/show_bug.cgi?id=21711 ).
For the new test case, codegen improves from:
vmovss %xmm0, (%rdi)
vextractps $1, %xmm0, 4(%rdi)
vextractps $2, %xmm0, 8(%rdi)
vextractps $3, %xmm0, 12(%rdi)
vextractf128 $1, %ymm0, %xmm0
vmovss %xmm0, 16(%rdi)
vextractps $1, %xmm0, 20(%rdi)
vextractps $2, %xmm0, 24(%rdi)
vextractps $3, %xmm0, 28(%rdi)
vzeroupper
retq
To:
vmovups %ymm0, (%rdi)
vzeroupper
retq
Patch reviewed by Nadav Rotem.
Differential Revision: http://reviews.llvm.org/D6698
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224611
91177308-0d34-0410-b5e6-
96231b3b80d8