[PATCH] D36996: [X86] Prevent several calls to ISD::isConstantSplatVector from returning a narrower APInt than the original scalar type

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.

ISD::isConstantSplatVector can shrink to the smallest splat width. But we don't check the size of the resulting APInt at all. This can cause us to misinterpret the results.

This patch just adds a flag to prevent the APInt from changing width.

Fixes PR34271.


https://reviews.llvm.org/D36996

Files:
  include/llvm/CodeGen/SelectionDAGNodes.h
  lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/pr34271-1.ll
  test/CodeGen/X86/pr34271.ll

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