Merging r263627:

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r263627 | michel.daenzer | 2016-03-16 02:10:42 -0700 (Wed, 16 Mar 2016) | 11 lines

AMDGPU: Verify instructions in non-debug builds as well

And emit an error if it fails.

This prevents illegal instructions from getting sent to the GPU, which
would potentially result in a hang.

This is a candidate for the stable branch(es).

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

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llvm-svn: 271724