diff options
Diffstat (limited to 'lib/CodeGen/SimpleRegisterCoalescing.cpp')
| -rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index 199c89e..7c512ed 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -247,11 +247,11 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA, unsigned CopyIdx = li_->getDefIndex(li_->getInstructionIndex(CopyMI)); - // FIXME: For now, only eliminate the copy by commuting its def is the source - // does not live pass the move. Coalescing those copies may end up may simply - // end up swapping a live interval for another. That and because usually only - // the non-two address operand can be folded can end up pessimizing the code. - if (CopyMI->findRegisterUseOperandIdx(IntA.reg, true) != -1) + // FIXME: For now, only eliminate the copy by commuting its def when the + // source register is a virtual register. We want to guard against cases + // where the copy is a back edge copy and commuting the def lengthen the + // live interval of the source register to the entire loop. + if (TargetRegisterInfo::isPhysicalRegister(IntA.reg)) return false; // BValNo is a value number in B that is defined by a copy from A. 'B3' in |