LSR ivchain bug fix: corner case with ConstantExpr.
Fixes PR11950.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153463 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index f211244..7e71683 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -704,8 +704,9 @@
Value *UVal = U->getValue();
for (Value::use_iterator UI = UVal->use_begin(), UE = UVal->use_end();
UI != UE; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- if (User->getOpcode() == Instruction::Mul
+ // If U is a constant, it may be used by a ConstantExpr.
+ Instruction *User = dyn_cast<Instruction>(*UI);
+ if (User && User->getOpcode() == Instruction::Mul
&& SE.isSCEVable(User->getType())) {
return SE.getSCEV(User) == Mul;
}