156d7d2df7
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
20 lines
1.1 KiB
YAML
20 lines
1.1 KiB
YAML
# 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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# GCN-NEXT: undef %3.sub0:vreg_64 = nofpexcept V_MAC_F32_e32 undef %1:vgpr_32, undef %1:vgpr_32, undef %3.sub0, implicit $mode, implicit $exec
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# GCN-NEXT: FLAT_STORE_DWORD undef %4:vreg_64, %3.sub0,
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---
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name: dead_lane
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tracksRegLiveness: true
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body: |
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bb.0:
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%1:vgpr_32 = nofpexcept V_MAC_F32_e32 undef %0:vgpr_32, undef %0:vgpr_32, undef %0:vgpr_32, implicit $mode, implicit $exec
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%2:vgpr_32 = nofpexcept V_MAC_F32_e32 undef %0:vgpr_32, undef %0:vgpr_32, undef %0:vgpr_32, implicit $mode, implicit $exec
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%3:vreg_64 = REG_SEQUENCE %1:vgpr_32, %subreg.sub0, %2:vgpr_32, %subreg.sub1
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FLAT_STORE_DWORD undef %4:vreg_64, %3.sub0, 0, 0, implicit $exec, implicit $flat_scr
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S_ENDPGM 0
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...
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