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[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

llvm-svn: 243745
This commit is contained in:
Daniel Sanders 2015-07-31 12:58:55 +00:00
parent adf1fcc2a5
commit e82f2947fd
1 changed files with 8 additions and 0 deletions
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8
llvm/lib/CodeGen/RegisterCoalescer.cpp
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@ -1531,6 +1531,14 @@ bool RegisterCoalescer::joinReservedPhysReg(CoalescerPair &CP) {
DEBUG(dbgs() << "\t\tInterference (read): " << *MI);
return false;
}
// We must also check for clobbers caused by regmasks.
for (const auto &MO : MI->operands()) {
if (MO.isRegMask() && MO.clobbersPhysReg(DstReg)) {
DEBUG(dbgs() << "\t\tInterference (regmask clobber): " << *MI);
return false;
}
}
}
// We're going to remove the copy which defines a physical reserved