Merge r324353 into the 6.0 branch

[llvmbot]

Bugzilla Link	36282
Resolution	FIXED
Resolved on	Feb 19, 2018 05:55
Version	6.0
OS	Linux
Blocks	#35152
Reporter	LLVM Bugzilla Contributor
CC	@zmodem

Extended Description

r324353 fixes a GPU hang due to to a pseudo instruction generated with a new pattern not having SGPR->VGPR promotion support.

"AMDGPU: Fix S_BUFFER_LOAD_DWORD_SGPR moveToVALU.

It moves the offset to vgpr, but did not handle being called for
any of the other arguments, while LLVM 5 would select
BUFFER_LOAD_DWORD_OFFEN immediately, which does the right thing.

This calls legalizeOperands to fix up the operands after we converted
to a BUFFER_LOAD_DWORD_OFFEN."

[llvmbot]

Can this be merged please to avoid the GPU hang?

[zmodem]

Merged in r325497.