diff options
Diffstat (limited to 'lib/CodeGen/RegisterCoalescer.cpp')
| -rw-r--r-- | lib/CodeGen/RegisterCoalescer.cpp | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index ff9bca092dbe..a67d07b36474 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -1227,6 +1227,34 @@ bool RegisterCoalescer::reMaterializeTrivialDef(const CoalescerPair &CP, SR->createDeadDef(DefIndex, Alloc); } } + + // Make sure that the subrange for resultant undef is removed + // For example: + // vreg1:sub1<def,read-undef> = LOAD CONSTANT 1 + // vreg2<def> = COPY vreg1 + // ==> + // vreg2:sub1<def, read-undef> = LOAD CONSTANT 1 + // ; Correct but need to remove the subrange for vreg2:sub0 + // ; as it is now undef + if (NewIdx != 0 && DstInt.hasSubRanges()) { + // The affected subregister segments can be removed. + SlotIndex CurrIdx = LIS->getInstructionIndex(NewMI); + LaneBitmask DstMask = TRI->getSubRegIndexLaneMask(NewIdx); + bool UpdatedSubRanges = false; + for (LiveInterval::SubRange &SR : DstInt.subranges()) { + if ((SR.LaneMask & DstMask).none()) { + DEBUG(dbgs() << "Removing undefined SubRange " + << PrintLaneMask(SR.LaneMask) << " : " << SR << "\n"); + // VNI is in ValNo - remove any segments in this SubRange that have this ValNo + if (VNInfo *RmValNo = SR.getVNInfoAt(CurrIdx.getRegSlot())) { + SR.removeValNo(RmValNo); + UpdatedSubRanges = true; + } + } + } + if (UpdatedSubRanges) + DstInt.removeEmptySubRanges(); + } } else if (NewMI.getOperand(0).getReg() != CopyDstReg) { // The New instruction may be defining a sub-register of what's actually // been asked for. If so it must implicitly define the whole thing. |