[PATCH] D109074: [Codegen][TLI][X86] SimplifyMultipleUseDemandedBits(): 0'th vec subreg widening is free, try to perform it earlier

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon accepted this revision.
RKSimon added a comment.
This revision is now accepted and ready to land.

LGTM with one minor - cheers



================
Comment at: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp:826
+    EVT SubVT = Sub.getValueType();
+    unsigned NumSubElts = SubVT.getVectorNumElements();
+    APInt DemandedSubElts = DemandedElts.extractBits(NumSubElts, Idx);
----------------
There is only one use of SubVT again, so you can revert this back to:
```
unsigned NumSubElts = Sub.getValueType().getVectorNumElements();
```


Repository:
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https://reviews.llvm.org/D109074