Fixed optimization of combining two shuffles where the first shuffle inputs

has a different number of elements than the output.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62998 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 40289ea..7f75928 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -12179,9 +12179,11 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
       // If the result mask is equal to the src shuffle or this shuffle mask, do
       // the replacement.
       if (NewMask == LHSMask || NewMask == Mask) {
+        unsigned LHSInNElts =
+          cast<VectorType>(LHSSVI->getOperand(0)->getType())->getNumElements();
         std::vector<Constant*> Elts;
         for (unsigned i = 0, e = NewMask.size(); i != e; ++i) {
-          if (NewMask[i] >= e*2) {
+          if (NewMask[i] >= LHSInNElts*2) {
             Elts.push_back(UndefValue::get(Type::Int32Ty));
           } else {
             Elts.push_back(ConstantInt::get(Type::Int32Ty, NewMask[i]));