[PATCH] D52304: [X86][BMI1]: X86DAGToDAGISel: select BEXTR from x & ~(-1 << nbits) pattern

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


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Comment at: lib/Target/X86/X86ISelDAGToDAG.cpp:2697
+  // All the other bits are undefined, we do not care about them.
+  SDValue Undef = CurDAG->getUNDEF(NVT);
+  insertDAGNode(*CurDAG, NBits, Undef);
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craig.topper wrote:
> Shouldn't we be using TargetOpcode::IMPLICIT_DEF not Undef?
Hm, i thought i tried that initially.
But this current version is the only one that did not contain unneeded extra moves.
I will double-check.


Repository:
  rL LLVM

https://reviews.llvm.org/D52304