Merging r167948, r168198: into the 3.2 release branch

r168198

[NVPTX] Order global variables in def-use order before emiting them in the final assembly


r167948

[NVPTX] Implement custom lowering of loads/stores for i1

Loads from i1 become loads from i8 followed by trunc
Stores to i1 become zext to i8 followed by store to i8

llvm-svn: 168335