llvm/test/CodeGen/AArch64/ldst-opt.mir
Tim Northover 6649090b22 AArch64: remove all kill flags when extending register liveness.
When we forward a stored value to a load and eliminate it entirely we need to
make sure the liveness of the register is maintained all the way to its use.
Previously we only cleared liveness on the store doing the forwarding, but
there could be other killing uses in between.

We already do the right thing when the load has to be converted into something
else, it was just this one path that skipped it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306318 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-26 18:49:25 +00:00

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# RUN: llc -mtriple=aarch64--linux-gnu -run-pass=aarch64-ldst-opt %s -verify-machineinstrs -o - | FileCheck %s
---
name: promote-load-from-store
tracksRegLiveness: true
body: |
bb.0:
liveins: %w1, %x0, %lr
STRWui killed %w1, %x0, 0 :: (store 4)
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
%w0 = LDRHHui killed %x0, 1 :: (load 2)
RET %lr, implicit %w0
...
# Don't count transient instructions towards search limits.
# CHECK-LABEL: name: promote-load-from-store
# CHECK: STRWui %w1
# CHECK: UBFMWri killed %w1
---
name: store-pair
tracksRegLiveness: true
body: |
bb.0:
liveins: %w1, %x0, %lr
STRWui %w1, %x0, 0 :: (store 4)
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
CFI_INSTRUCTION 0
STRWui killed %w1, killed %x0, 1 :: (store 4)
RET %lr
...
# CHECK-LABEL: name: store-pair
# CHECK: STPWi
---
name: store-pair-clearkill0
tracksRegLiveness: true
body: |
bb.0:
liveins: %w1, %x0, %lr
STRWui %w1, %x0, 0 :: (store 4)
%w2 = COPY %w1
%x3 = COPY %x0
STRWui killed %w1, killed %x0, 1 :: (store 4)
RET %lr
...
# When merging a lower store with an upper one, we must clear kill flags on
# the lower store.
# CHECK-LABEL: store-pair-clearkill0
# CHECK-NOT: STPWi %w1, killed %w1, %x0, 0 :: (store 4)
# CHECK: STPWi %w1, %w1, %x0, 0 :: (store 4)
# CHECK: %w2 = COPY %w1
# CHECK: RET %lr
---
name: store-pair-clearkill1
tracksRegLiveness: true
body: |
bb.0:
liveins: %x0, %lr
%w1 = MOVi32imm 13
%w2 = MOVi32imm 7
STRWui %w1, %x0, 1 :: (store 4)
%w2 = COPY killed %w1
STRWui killed %w2, %x0, 0 :: (store 4)
%w1 = MOVi32imm 42
%w2 = MOVi32imm 7
STRWui %w1, %x0, 0 :: (store 4)
%w2 = COPY killed %w1
STRWui killed %w2, killed %x0, 1 :: (store 4)
RET %lr
...
# When merging an upper store with a lower one, kill flags along the way need
# to be removed; In this case the kill flag on %w1.
# CHECK-LABEL: store-pair-clearkill1
# CHECK: %w1 = MOVi32imm
# CHECK: %w2 = MOVi32imm
# CHECK-NOT: %w2 = COPY killed %w1
# CHECK: %w2 = COPY %w1
# CHECK: STPWi killed %w2, %w1, %x0, 0
# CHECK: %w1 = MOVi32imm
# CHECK: %w2 = MOVi32imm
# CHECK-NOT: %w2 = COPY killed %w1
# CHECK: %w2 = COPY %w1
# CHECK: STPWi %w1, killed %w2, killed %x0, 0
---
name: store-load-clearkill
tracksRegLiveness: true
body: |
bb.0:
liveins: %w1
STRWui %w1, %sp, 0 :: (store 4)
%wzr = COPY killed %w1 ; killing use of %w1
%w11 = LDRWui %sp, 0 :: (load 4)
HINT 0, implicit %w11 ; some use of %w11
...
# When replaceing the load of a store-load pair with a copy the kill flags
# along the way need to be cleared.
# CHECK-LABEL: name: store-load-clearkill
# CHECK: STRWui %w1, %sp, 0 :: (store 4)
# CHECK-NOT: COPY killed %w1
# CHECK: %wzr = COPY %w1
# CHECK: %w11 = ORRWrs %wzr, %w1, 0
# CHECK: HINT 0, implicit %w11
---
name: promote-load-from-store-undef
tracksRegLiveness: true
body: |
bb.0:
liveins: %x0, %x2, %lr
STRWui undef %w1, %x0, 0 :: (store 4)
%w0 = LDRBBui %x0, 1 :: (load 2)
STRHHui undef %w3, %x2, 0 :: (store 4)
%w1 = LDRBBui %x2, 0 :: (load 4)
RET %lr, implicit %w0
...
# CHECK-LABEL: name: promote-load-from-store-undef
# CHECK: STRWui undef %w1
# CHECK: UBFMWri undef %w1
# CHECK: STRHHui undef %w3
# CHECK: ANDWri undef %w3
---
name: promote-load-from-store-trivial-kills
tracksRegLiveness: true
body: |
bb.0:
liveins: %x0, %lr
STRXui %x0, %sp, 0 :: (store 8)
STRXui killed %x0, %sp, 2 :: (store 8)
%x0 = LDRXui %sp, 0 :: (load 8)
BL $bar, csr_aarch64_aapcs, implicit-def %lr, implicit %sp, implicit %x0, implicit-def %sp
RET %lr
...
# CHECK-LABEL: name: promote-load-from-store-trivial-kills
# CHECK: STRXui %x0, %sp, 0
# CHECK: STRXui %x0, %sp, 2
# CHECK-NOT: LDRXui
# CHECK-NOT: ORR
# CHECK: BL $bar, csr_aarch64_aapcs, implicit-def %lr, implicit %sp, implicit %x0, implicit-def %sp