[llvm] r331508 - [IRCE] Fix misuse of dyn_cast which leads to UB

[Max Kazantsev via llvm-commits]

Author: mkazantsev
Date: Fri May  4 00:34:35 2018
New Revision: 331508

URL: http://llvm.org/viewvc/llvm-project?rev=331508&view=rev
Log:
[IRCE] Fix misuse of dyn_cast which leads to UB

Modified:
    llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp?rev=331508&r1=331507&r2=331508&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp Fri May  4 00:34:35 2018
@@ -925,11 +925,12 @@ LoopStructure::parseLoopStructure(Scalar
     return None;
   }
   const SCEV* StepRec = IndVarBase->getStepRecurrence(SE);
-  ConstantInt *StepCI = dyn_cast<SCEVConstant>(StepRec)->getValue();
-  if (!StepCI) {
+  if (!isa<SCEVConstant>(StepRec)) {
     FailureReason = "LHS in icmp not induction variable";
     return None;
   }
+  ConstantInt *StepCI = cast<SCEVConstant>(StepRec)->getValue();
+
   if (ICI->isEquality() && !HasNoSignedWrap(IndVarBase)) {
     FailureReason = "LHS in icmp needs nsw for equality predicates";
     return None;