[PATCH] D125238: [X86] Prefer MOVHLPS for shuffle(x, 1, -1) extraction patterns (PR26515)

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/test/CodeGen/X86/vector-reduce-fadd.ll:54
+; SSE2-NEXT:    xorps %xmm2, %xmm2
+; SSE2-NEXT:    movhlps {{.*#+}} xmm2 = xmm1[1],xmm2[1]
 ; SSE2-NEXT:    addss %xmm2, %xmm0
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RKSimon wrote:
> TBH I'm not convinced any of these need dependency breaks.
Will it always insert a dependency break because it can't rewrite the tied dest?


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  https://reviews.llvm.org/D125238/new/

https://reviews.llvm.org/D125238