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[AArch64][LoadStoreOptimizer] Ignore undef registers when checking r…
…ename register used between paired instructions. The content of undef registers are not used in meaningful ways, when checking if a rename register is used between paired instructions we should ignore undef registers. Reviewed By: efriedma Differential Revision: https://reviews.llvm.org/D119305
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llvm/test/CodeGen/AArch64/stp-opt-with-renaming-undef-assert.mir
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# RUN: llc -run-pass=aarch64-ldst-opt -mtriple=aarch64 -verify-machineinstrs -o - %s | FileCheck %s | ||
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# This test checks that aarch64 load store optimizer is not throwing an | ||
# assertion: | ||
# "Rename register used between paired instruction, trashing the content". | ||
# | ||
# The assertion was previously triggered because q16 is picked as renamable | ||
# register, which overlap with renamable undef d16 used by ZIP2 instruction. | ||
# However, the content of an undef register is not used in meaningful way, | ||
# aarch64 load store optimizer should not throw an assertion if a renamable | ||
# register picked overlap with a renamable undef register. | ||
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# This test also checks that pairwise store STP is generated. | ||
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# CHECK-LABLE: test | ||
# CHECK: bb.0: | ||
# CHECK-NEXT: liveins: $x0, $x17, $x18 | ||
# CHECK: renamable $q13_q14_q15 = LD3Threev16b undef renamable $x17 :: (load (s384) from `<16 x i8>* undef`, align 64) | ||
# CHECK-NEXT: renamable $q23_q24_q25 = LD3Threev16b undef renamable $x18 :: (load (s384) from `<16 x i8>* undef`, align 64) | ||
# CHECK-NEXT: $q16 = EXTv16i8 renamable $q23, renamable $q23, 8 | ||
# CHECK-NEXT: renamable $q20 = EXTv16i8 renamable $q14, renamable $q14, 8 | ||
# CHECK-NEXT: STRQui killed renamable $q20, $sp, 4 :: (store (s128) into %stack.3) | ||
# CHECK-NEXT: renamable $d6 = ZIP2v8i8 renamable $d23, undef renamable $d16 | ||
# CHECK-NEXT: STRDui killed renamable $d6, $sp, 11 :: (store (s64) into %stack.2) | ||
# CHECK-NEXT: renamable $q6 = EXTv16i8 renamable $q13, renamable $q13, 8 | ||
# CHECK-NEXT: STPQi killed renamable $q6, killed $q16, $sp, 6 :: (store (s128) into %stack.0), (store (s128) into %stack.1) | ||
# CHECK-NEXT: RET undef $lr | ||
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--- | ||
name: test | ||
alignment: 4 | ||
tracksRegLiveness: true | ||
liveins: | ||
- { reg: '$x0', virtual-reg: '' } | ||
frameInfo: | ||
maxAlignment: 16 | ||
maxCallFrameSize: 0 | ||
fixedStack: [] | ||
stack: | ||
- { id: 0, name: '', type: spill-slot, offset: -80, size: 16, alignment: 16, | ||
stack-id: default, callee-saved-register: '', callee-saved-restored: true, | ||
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' } | ||
- { id: 1, name: '', type: spill-slot, offset: -96, size: 16, alignment: 16, | ||
stack-id: default, callee-saved-register: '', callee-saved-restored: true, | ||
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' } | ||
- { id: 2, name: '', type: spill-slot, offset: -104, size: 8, alignment: 8, | ||
stack-id: default, callee-saved-register: '', callee-saved-restored: true, | ||
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' } | ||
- { id: 3, name: '', type: spill-slot, offset: -128, size: 16, alignment: 16, | ||
stack-id: default, callee-saved-register: '', callee-saved-restored: true, | ||
debug-info-variable: '', debug-info-expression: '', debug-info-location: '' } | ||
machineFunctionInfo: {} | ||
body: | | ||
bb.0: | ||
liveins: $x0, $x17, $x18 | ||
renamable $q13_q14_q15 = LD3Threev16b undef renamable $x17 :: (load (s384) from `<16 x i8>* undef`, align 64) | ||
renamable $q23_q24_q25 = LD3Threev16b undef renamable $x18 :: (load (s384) from `<16 x i8>* undef`, align 64) | ||
renamable $q20 = EXTv16i8 renamable $q23, renamable $q23, 8 | ||
STRQui killed renamable $q20, $sp, 7 :: (store (s128) into %stack.0) | ||
renamable $q20 = EXTv16i8 renamable $q14, renamable $q14, 8 | ||
STRQui killed renamable $q20, $sp, 4 :: (store (s128) into %stack.3) | ||
renamable $d6 = ZIP2v8i8 renamable $d23, undef renamable $d16 | ||
STRDui killed renamable $d6, $sp, 11 :: (store (s64) into %stack.2) | ||
renamable $q6 = EXTv16i8 renamable $q13, renamable $q13, 8 | ||
STRQui killed renamable $q6, $sp, 6 :: (store (s128) into %stack.1) | ||
RET undef $lr | ||
... |