[PATCH] D53760: [SelectionDAG] Add FoldBUILD_VECTOR to simplify new BUILD_VECTOR nodes

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: spatel, efriedma, majnemer, arsenm.
Herald added subscribers: tpr, nhaehnle, wdng, jvesely.

Similar to FoldCONCAT_VECTORS, this patch adds FoldBUILD_VECTOR to simplify cases that can avoid the creation of the BUILD_VECTOR - if all the operands are UNDEF or if the BUILD_VECTOR simplifies to a copy.

This exposed an assumption in some AMDGPU code that getBuildVector was guaranteed to be a BUILD_VECTOR node that I've tried to handle.


Repository:
  rL LLVM

https://reviews.llvm.org/D53760

Files:
  lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  lib/Target/AMDGPU/R600ISelLowering.cpp
  test/CodeGen/AMDGPU/load-local-i16.ll
  test/CodeGen/X86/clear_upper_vector_element_bits.ll
  test/CodeGen/X86/lower-vec-shift.ll

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