[PATCH] D61806: [DAGCombiner] try to move bitcast after extract_subvector

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:17595
+    unsigned DestNumElts = V.getValueType().getVectorNumElements();
+    if (SrcNumElts >= DestNumElts) {
+      unsigned SrcDestRatio = SrcNumElts / DestNumElts;
----------------
Its typically safer to do (SrcNumElts % DestNumElts) == 0


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Comment at: llvm/test/CodeGen/X86/sad.ll:1452
 ; AVX2-NEXT:    vmovd %xmm0, %eax
 ; AVX2-NEXT:    vzeroupper
 ; AVX2-NEXT:    retq
----------------
weird - if this is all xmm code now why hasn't the vzeroupper gone?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D61806/new/

https://reviews.llvm.org/D61806