MemCpyOptimizer: Use max legal int size instead of pointer size

If there are no legal integers, assume 1 byte.

This makes more sense than using the pointer size as
a guess for the maximum GPR width.

It is conceivable to want to use some 64-bit pointers
on a target where 64-bit integers aren't legal.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190817 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/DataLayout.cpp

@@ -629,6 +629,13 @@ Type *DataLayout::getSmallestLegalIntType(LLVMContext &C, unsigned Width) const
   return 0;
 }
 
+unsigned DataLayout::getLargestLegalIntTypeSize() const {
+  unsigned MaxWidth = 0;
+  for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
+    MaxWidth = std::max<unsigned>(MaxWidth, LegalIntWidths[i]);
+  return MaxWidth;
+}
+
 uint64_t DataLayout::getIndexedOffset(Type *ptrTy,
                                       ArrayRef<Value *> Indices) const {
   Type *Ty = ptrTy;