Compare DataLayout by Value, not by pointer.

This fixes spurious warnings in llvm-link about the datalayout not matching.

Thanks to Zalman Stern for reporting the bug!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202276 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/DataLayout.h

@@ -193,6 +193,9 @@ public:
     return *this;
   }
 
+  bool operator==(const DataLayout &Other) const;
+  bool operator!=(const DataLayout &Other) const { return !(*this == Other); }
+
   ~DataLayout();  // Not virtual, do not subclass this class
 
   /// Parse a data layout string (with fallback to default values).