DAGCombiner: Merge store/loads when we have extload/truncstores

[Arnold Schwaighofer]

DAGCombiner: Merge store/loads when we have extload/truncstores

This is helps on architectures where i8,i16 are not legal but we have byte,
and short loads/stores like on ARM.

Allowing us to merge copies like the one below on ARM.

copy(char *a, char *b, int n) {
  do {
    int t0 = a[0];
    int t1 = a[1];
    b[0] = t0;
    b[1] = t1;

radar://13536387

-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-DAGCombiner-Merge-store-loads-when-we-have-extload-t.patch
Type: application/octet-stream
Size: 5898 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20130402/45083273/attachment.obj>