Merging r259546:

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r259546 | Matthew.Arsenault | 2016-02-02 11:18:53 -0800 (Tue, 02 Feb 2016) | 5 lines

AMDGPU: Whitelist handled intrinsics

We shouldn't crash on unhandled intrinsics.
Also simplify failure handling in loop.

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llvm-svn: 271592