diff options
| -rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index 17a8908..199c89e 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -247,6 +247,13 @@ 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) + return false; + // BValNo is a value number in B that is defined by a copy from A. 'B3' in // the example above. LiveInterval::iterator BLR = IntB.FindLiveRangeContaining(CopyIdx); |