[all-commits] [llvm/llvm-project] 76123d: [DAGCombiner] visitSIGN_EXTEND_INREG should fold s...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 76123d338dc542d25cc9c4f20ddc49df1b9712cd
      https://github.com/llvm/llvm-project/commit/76123d338dc542d25cc9c4f20ddc49df1b9712cd
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-07-04 (Sat, 04 Jul 2020)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

  Log Message:
  -----------
  [DAGCombiner] visitSIGN_EXTEND_INREG should fold sext_vector_inreg(undef) to 0 not undef.

We need to ensure that the sign bits of the result all match
so we can't fold to undef.

Similar to PR46585.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D83163