Fix accidentally constant conditions found by uncommitted improvements to -Wconstant-conversion.

A couple of cases where we were accidentally creating constant conditions by
something like "x == a || b" instead of "x == a || x == b". In one case a
conditional & then unreachable was used - I transformed this into a direct
assert instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154324 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Instructions.h

@@ -2507,7 +2507,8 @@ public:
     
     /// Resolves successor for current case.
     BasicBlockTy *getCaseSuccessor() {
-      assert((Index < SI->getNumCases() || DefaultPseudoIndex) &&
+      assert((Index < SI->getNumCases() ||
+              Index == DefaultPseudoIndex) &&
              "Index out the number of cases.");
       return SI->getSuccessor(getSuccessorIndex());      
     }