Merge r355227 and r355228 to 8.0

[topperc]

Bugzilla Link	40960
Resolution	FIXED
Resolved on	Mar 05, 2019 09:46
Version	8.0
OS	Windows NT
Blocks	#39678
CC	@dbabokin,@topperc,@zmodem,@RKSimon,@rotateright

Extended Description

Hans, is it possible to merge this to 8.0. I know we're getting pretty late.

ISPC folks tell me they are seeing a regression on some test cases with 8.0 that these commits fix.

The gather/scatter intrinsics have been misdeclared for a long time probably since they were added years ago. My reduced test case fails on previous versions llvm.

So I think that means that ISPC is hitting some other optimization change that made them more susceptible to this issue.

[zmodem]

We already need to do an rc4, so merging sounds fine. r355383.

[dbabokin]

Thanks Hans! Now we can build with LLVM 8.0 without patches.