Fix uninitialized variable warning in cppcheck. NFCI.

InstCombiner::MaxArraySizeForCombine is set outside the constructor so we need to ensure it has a default initialization value.

llvm-svn: 370220

llvm/lib/Transforms/InstCombine/InstCombineInternal.h

@@ -739,7 +739,7 @@ public:
       Value *LHS, Value *RHS, Instruction *CxtI) const;
 
   /// Maximum size of array considered when transforming.
-  uint64_t MaxArraySizeForCombine;
+  uint64_t MaxArraySizeForCombine = 0;
 
 private:
   /// Performs a few simplifications for operators which are associative