IR: Fix ConstantArray::replaceUsesOfWithOnConstant()

Previously, `ConstantArray::replaceUsesOfWithOnConstant()` neglected to
check whether it becomes a `ConstantDataArray`.  Call
`ConstantArray::getImpl()` to check for that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215965 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/Constants.cpp

@@ -2701,6 +2701,12 @@ void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
     return;
   }
 
+  // Check for any other type of constant-folding.
+  if (Constant *C = getImpl(getType(), Values)) {
+    replaceUsesOfWithOnConstantImpl(C);
+    return;
+  }
+
   // Check to see if we have this array type already.
   LLVMContextImpl::ArrayConstantsTy::LookupKey Lookup(
     cast<ArrayType>(getType()), makeArrayRef(Values));