Ahmed Bougacha 8081057fca [MemCpyOpt] Turn memcpy from just-memset'd source into memset.
There's no point in copying around constants, so, when all else fails,
we can still transform memcpy of memset into two independent memsets.

To quote the example, we can turn:
  memset(dst1, c, dst1_size);
  memcpy(dst2, dst1, dst2_size);
into:
  memset(dst1, c, dst1_size);
  memset(dst2, c, dst2_size);
When dst2_size <= dst1_size.

Like r235232 for copy constructors, this can occur in move constructors.

Differential Revision: http://reviews.llvm.org/D9682


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237506 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-16 01:32:26 +00:00
..