Merging r243661:

Merging r243661:

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r243661 | Matthew.Arsenault | 2015-07-30 13:03:11 -0400 (Thu, 30 Jul 2015) | 6 lines

AMDGPU: Set SubRegIndex size and offset

I'm not sure what reasons the comment here could have
had for not setting these. Without these set, there is
an assertion hit during DWARF emission.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_37@253230 91177308-0d34-0410-b5e6-96231b3b80d8