Merging r243745:

Merging r243745:
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r243745 | dsanders | 2015-07-31 13:58:55 +0100 (Fri, 31 Jul 2015) | 17 lines

[regalloc] Make RegMask clobbers prevent merging vreg's into PhysRegs when hoisting def's upwards.

Summary:
This prevents vreg260 and D7 from being merged in:
  %vreg260<def> = LDC1 ...
  JAL <ga:@sin>, <regmask ... list not containing D7 ...>
  %D7<def> = COPY %vreg260; ...
Doing so is not valid because the JAL clobbers the D7.

This fixes the almabench regression in the LLVM 3.7.0 release branch.

Reviewers: MatzeB

Subscribers: MatzeB, qcolombet, hans, llvm-commits

Differential Revision: http://reviews.llvm.org/D11649

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_37@243834 91177308-0d34-0410-b5e6-96231b3b80d8