Merging r260692:

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r260692 | changpeng.fang | 2016-02-12 09:11:04 -0800 (Fri, 12 Feb 2016) | 13 lines

AMDGPU/SI: Annotate Loops with Constant Condition in SIAnnotateControlFlow pass.

Summary:
  It is possible that the loop condition can be a boolean constant (infinite loop,
for example). So we sould handle constant condition in annotating a loop. This
patch adds this functionality to support annotating constant condition.

Reviewers: tstellarAMD, arsenm

Subscribers: llvm-commits, arsenm

Differential Revision: http://reviews.llvm.org/D15093

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llvm-svn: 271685