Only do switch-to-lookup table transformation when TargetTransformInfo
is available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167552 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 9823433..b33d0d4 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -3538,7 +3538,8 @@
                                 const TargetTransformInfo *TTI) {
   assert(SI->getNumCases() > 1 && "Degenerate switch?");
 
-  if (TTI && !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables())
+  // Only build lookup table when we have a target that supports it.
+  if (!TTI || !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables())
     return false;
 
   // FIXME: If the switch is too sparse for a lookup table, perhaps we could