[llvm] r243302 - Revert "Remove unnecessary null check. NFC."

[Pete Cooper]

Author: pete
Date: Mon Jul 27 13:37:58 2015
New Revision: 243302

URL: http://llvm.org/viewvc/llvm-project?rev=243302&view=rev
Log:
Revert "Remove unnecessary null check.  NFC."

This reverts commit r243167.

Duncan pointed out that dyn_cast can return null in these cases, so this
was an unsafe commit to make.  Sorry for the noise.

Worryingly there were no tests which fail...

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

Modified: llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp?rev=243302&r1=243301&r2=243302&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopInterchange.cpp Mon Jul 27 13:37:58 2015
@@ -817,6 +817,9 @@ bool LoopInterchangeLegality::currentLim
     InnerIndexVarInc =
         dyn_cast<Instruction>(InnerInductionVar->getIncomingValue(0));
 
+  if (!InnerIndexVarInc)
+    return true;
+
   // Since we split the inner loop latch on this induction variable. Make sure
   // we do not have any instruction between the induction variable and branch
   // instruction.