401d123a1f
Before this patch, redundant COPY couldn't be removed for the following case: ``` $R0 = OP ... ... // Read of %R0 $R1 = COPY killed $R0 ``` This patch adds support for tracking the users of the source register during backward propagation, so that we can remove the redundant COPY in the above case and optimize it to: ``` $R1 = OP ... ... // Replace all uses of %R0 with $R1 ```
59 lines
1.8 KiB
YAML
59 lines
1.8 KiB
YAML
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
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# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass machine-cp -verify-machineinstrs -o - %s | FileCheck %s
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# Normal case
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---
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name: test1
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body: |
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bb.0:
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liveins: $w2
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; CHECK-LABEL: name: test1
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; CHECK: liveins: $w2
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; CHECK-NEXT: {{ $}}
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; CHECK-NEXT: renamable $w0 = MOVi32imm 5
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; CHECK-NEXT: renamable $w3 = ADDWrr renamable $w0, killed renamable $w2
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; CHECK-NEXT: RET_ReallyLR implicit killed $w0
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renamable $w1 = MOVi32imm 5
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renamable $w3 = ADDWrr renamable $w1, killed renamable $w2
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renamable $w0 = COPY killed renamable $w1
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RET_ReallyLR implicit killed $w0
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...
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# Not renamable use
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---
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name: test2
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body: |
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bb.0:
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liveins: $w2
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; CHECK-LABEL: name: test2
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; CHECK: liveins: $w2
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; CHECK-NEXT: {{ $}}
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; CHECK-NEXT: renamable $w1 = MOVi32imm 5
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; CHECK-NEXT: renamable $w3 = ADDWrr $w1, killed renamable $w2
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; CHECK-NEXT: renamable $w0 = COPY killed renamable $w1
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; CHECK-NEXT: RET_ReallyLR implicit killed $w0
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renamable $w1 = MOVi32imm 5
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renamable $w3 = ADDWrr $w1, killed renamable $w2
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renamable $w0 = COPY killed renamable $w1
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RET_ReallyLR implicit killed $w0
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...
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# Implicit use
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---
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name: test3
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body: |
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bb.0:
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liveins: $w2
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; CHECK-LABEL: name: test3
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; CHECK: liveins: $w2
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; CHECK-NEXT: {{ $}}
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; CHECK-NEXT: renamable $w1 = MOVi32imm 5
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; CHECK-NEXT: renamable $w3 = ADDWrr renamable $w1, killed renamable $w2, implicit $w1
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; CHECK-NEXT: renamable $w0 = COPY killed renamable $w1
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; CHECK-NEXT: RET_ReallyLR implicit killed $w0
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renamable $w1 = MOVi32imm 5
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renamable $w3 = ADDWrr renamable $w1, killed renamable $w2, implicit $w1
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renamable $w0 = COPY killed renamable $w1
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RET_ReallyLR implicit killed $w0
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...
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