X86 pmovsx/pmovzx ignore the upper half of their inputs.
rdar://problem/6945110
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131493 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 726105f..83653fd 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -588,6 +588,28 @@
break;
}
+
+ case Intrinsic::x86_sse41_pmovsxbw:
+ case Intrinsic::x86_sse41_pmovsxwd:
+ case Intrinsic::x86_sse41_pmovsxdq:
+ case Intrinsic::x86_sse41_pmovzxbw:
+ case Intrinsic::x86_sse41_pmovzxwd:
+ case Intrinsic::x86_sse41_pmovzxdq: {
+ unsigned VWidth =
+ cast<VectorType>(II->getArgOperand(0)->getType())->getNumElements();
+ unsigned LowHalfElts = VWidth / 2;
+ APInt InputDemandedElts(VWidth, 0);
+ InputDemandedElts = InputDemandedElts.getBitsSet(VWidth, 0, LowHalfElts);
+ APInt UndefElts(VWidth, 0);
+ if (Value *TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0),
+ InputDemandedElts,
+ UndefElts)) {
+ II->setArgOperand(0, TmpV);
+ return II;
+ }
+ break;
+ }
+
case Intrinsic::ppc_altivec_vperm:
// Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getArgOperand(2))) {