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llvm-svn: 131659
2011-05-19 18:18:39 +00:00 · 2011-05-19 18:18:39 +00:00 · dc867ae1fc
parent 92bb12ca3e
commit dc867ae1fc
1 changed files with 1 additions and 0 deletions
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@ -597,6 +597,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
  case Intrinsic::x86_sse41_pmovzxbw:
  case Intrinsic::x86_sse41_pmovzxwd:
  case Intrinsic::x86_sse41_pmovzxdq: {
+    // pmov{s|z}x ignores the upper half of their input vectors.
    unsigned VWidth =
      cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
    unsigned LowHalfElts = VWidth / 2;