Use modulo operator instead of multiplying result of a divide and subtracting from the original dividend. NFC.

llvm-svn: 253792
diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 7594956..5997464 100644
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -190,7 +190,7 @@
   unsigned NumPointerStores = Bytes / MaxIntSize;
 
   // Assume the remaining bytes if any are done a byte at a time.
-  unsigned NumByteStores = Bytes - NumPointerStores * MaxIntSize;
+  unsigned NumByteStores = Bytes % MaxIntSize;
 
   // If we will reduce the # stores (according to this heuristic), do the
   // transformation.  This encourages merging 4 x i8 -> i32 and 2 x i16 -> i32