forked from OSchip/llvm-project
[LiveIntervals] Remove unused subreg ranges in repairIntervalsInRange
If the old instructions mentioned a subreg that the new instructions do not, remove the subrange for that subreg. For example, in TwoAddressInstructionPass::eliminateRegSequence, if a use operand in the REG_SEQUENCE has the undef flag then we don't generate a copy for it so after the elimination there should be no live interval at all for the corresponding subreg of the def. This is a small step towards switching TwoAddressInstructionPass over from LiveVariables to LiveIntervals. Currently this path is only tested if you explicitly enable -early-live-intervals. Differential Revision: https://reviews.llvm.org/D110542
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@ -1655,6 +1655,10 @@ void LiveIntervals::repairOldRegInRange(const MachineBasicBlock::iterator Begin,
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}
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}
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}
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bool isStartValid = getInstructionFromIndex(LII->start);
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if (!isStartValid && LII->end.isDead())
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LR.removeSegment(*LII, true);
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}
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void
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@ -1716,6 +1720,7 @@ LiveIntervals::repairIntervalsInRange(MachineBasicBlock *MBB,
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for (LiveInterval::SubRange &S : LI.subranges())
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repairOldRegInRange(Begin, End, EndIdx, S, Reg, S.LaneMask);
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LI.removeEmptySubRanges();
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repairOldRegInRange(Begin, End, EndIdx, LI, Reg);
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}
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@ -1,4 +1,5 @@
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# RUN: llc -march=amdgcn -mcpu=tonga %s -start-before detect-dead-lanes -stop-before machine-scheduler -verify-machineinstrs -o - | FileCheck -check-prefix=GCN %s
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# RUN: llc -march=amdgcn -mcpu=tonga %s -start-before detect-dead-lanes -stop-before machine-scheduler -verify-machineinstrs -early-live-intervals -o - | FileCheck -check-prefix=GCN %s
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# GCN-LABEL: name: dead_lane
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# GCN: bb.0:
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@ -1,5 +1,6 @@
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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -mtriple=thumbv8.1m.main-none-none-eabi -mattr=+mve.fp,+fp64 -verify-machineinstrs -o - %s | FileCheck %s
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; RUN: llc -mtriple=thumbv8.1m.main-none-none-eabi -mattr=+mve.fp,+fp64 -verify-machineinstrs -early-live-intervals -o - %s | FileCheck %s
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define arm_aapcs_vfpcc <4 x float> @foo_v4i16(<4 x i16>* nocapture readonly %pSrc, i32 %blockSize, <4 x i16> %a) {
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; CHECK-LABEL: foo_v4i16:
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