Merge r311087 to 5.0

[llvmbot]

Bugzilla Link	34233
Resolution	FIXED
Resolved on	Aug 18, 2017 13:36
Version	5.0
OS	All
Blocks	#33196
Reporter	LLVM Bugzilla Contributor
CC	@zmodem,@RKSimon

Extended Description

Please merge r311087 "[dfsan] Add explicit zero extensions for shadow parameters in function wrappers." to 5.0, it fixes a long term bug in DFSan for MIPS.

[zmodem]

r311195. Thanks.