0c5319e546
Modulo variable expansion is a technique that resolves overlap of variable lifetimes by unrolling. The existing implementation solves it by making a copy by move instruction for processors with ordinary registers such as Arm and x86. This method may result in a very large number of move instructions, which can cause performance problems. Modulo variable expansion is enabled by specifying -pipeliner-mve-cg. A backend must implement some newly defined interfaces in PipelinerLoopInfo. They were implemented for AArch64. Discourse thread: https://discourse.llvm.org/t/implementing-modulo-variable-expansion-for-machinepipeliner
110 lines
2.5 KiB
YAML
110 lines
2.5 KiB
YAML
# RUN: llc --verify-machineinstrs -mtriple=aarch64 -o - %s -run-pass pipeliner -aarch64-enable-pipeliner -debug-only=pipeliner 2>&1 | FileCheck %s
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# REQUIRES: asserts
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# unacceptable loops by pipeliner
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...
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---
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name: func1
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tracksRegLiveness: true
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body: |
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; multiple counter increment instructions
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; CHECK: Unable to analyzeLoop, can NOT pipeline Loop
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bb.0.entry:
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liveins: $x0, $x1
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%10:gpr64 = COPY $x0
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%11:gpr64 = COPY $x1
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bb.1:
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%12:gpr64 = PHI %11, %bb.0, %13, %bb.1
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%13:gpr64 = ADDXrr %12, %11
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%14:gpr64 = ADDXrr %13, %11
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dead $xzr = SUBSXrr %10, %14, implicit-def $nzcv
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Bcc 1, %bb.1, implicit $nzcv
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B %bb.2
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bb.2:
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...
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---
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name: func2
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tracksRegLiveness: true
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body: |
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; neither operand of the increment instruction is a loop invariant value
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; CHECK: Unable to analyzeLoop, can NOT pipeline Loop
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bb.0.entry:
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liveins: $x0, $x1
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%10:gpr64 = COPY $x0
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%11:gpr64 = COPY $x1
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bb.1:
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%12:gpr64 = PHI %11, %bb.0, %13, %bb.1
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%13:gpr64 = ADDXrr %12, %12
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dead $xzr = SUBSXrr %10, %13, implicit-def $nzcv
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Bcc 1, %bb.1, implicit $nzcv
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B %bb.2
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bb.2:
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...
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---
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name: func3
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tracksRegLiveness: true
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body: |
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; neither operand of the compare instruction is a loop invariant value
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; CHECK: Unable to analyzeLoop, can NOT pipeline Loop
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bb.0.entry:
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liveins: $x0, $x1
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%10:gpr64 = COPY $x0
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%11:gpr64 = COPY $x1
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bb.1:
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%12:gpr64 = PHI %11, %bb.0, %13, %bb.1
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%13:gpr64 = ADDXrr %12, %11
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dead $xzr = SUBSXrr %13, %13, implicit-def $nzcv
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Bcc 1, %bb.1, implicit $nzcv
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B %bb.2
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bb.2:
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...
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---
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name: func4
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tracksRegLiveness: true
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body: |
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; multiple phi instructions
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; CHECK: Unable to analyzeLoop, can NOT pipeline Loop
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bb.0.entry:
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liveins: $x0, $x1
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%10:gpr64 = COPY $x0
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%11:gpr64 = COPY $x1
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bb.1:
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%12:gpr64 = PHI %11, %bb.0, %13, %bb.1
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%14:gpr64 = PHI %11, %bb.0, %15, %bb.1
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dead $xzr = SUBSXrr %12, %10, implicit-def $nzcv
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%13:gpr64 = ADDXrr %14, %11
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%15:gpr64 = ADDXrr %12, %11
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Bcc 1, %bb.1, implicit $nzcv
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B %bb.2
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bb.2:
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...
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---
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name: func5
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tracksRegLiveness: true
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body: |
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; not an increment instruction
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; CHECK: Unable to analyzeLoop, can NOT pipeline Loop
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bb.0.entry:
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liveins: $x0, $x1
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%10:gpr64 = COPY $x0
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%11:gpr64 = COPY $x1
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bb.1:
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%12:gpr64 = PHI %11, %bb.0, %13, %bb.1
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%13:gpr64 = ORRXrr %12, %12
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dead $xzr = SUBSXrr %12, %10, implicit-def $nzcv
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Bcc 1, %bb.1, implicit $nzcv
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B %bb.2
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bb.2:
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...
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