llvm/test/CodeGen/X86/fake-use-remove-loads.mir

# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
# Ensure that loads into FAKE_USEs are correctly removed by the
# remove-loads-into-fake-uses pass, and that if the function does not use
# instruction referencing then no changes are made.
# RUN: llc %s -run-pass remove-loads-into-fake-uses -mtriple=x86_64-unknown-linux -debug-only=remove-loads-into-fake-uses 2>&1 -o - | FileCheck %s
# RUN: llc %s -passes remove-loads-into-fake-uses -mtriple=x86_64-unknown-linux -debug-only=remove-loads-into-fake-uses 2>&1 -o - | FileCheck %s

# REQUIRES: asserts
#
## We verify that:
##   - The load into the FAKE_USE is removed, along with the FAKE_USE itself,
##     even when the FAKE_USE is for a subregister of the move.
##   - We correctly handle situations where FAKE_USE has additional `killed`
##     operands added by other passes.
##   - The store to the stack slot still exists.
##   - When the register has a use between the restore and the FAKE_USE, we do
##     not delete the load or fake use.


---
name:            enabled
alignment:       16
tracksRegLiveness: true
noPhis:          true
noVRegs:         true
hasFakeUses:     true
tracksDebugUserValues: true
debugInstrRef: true
liveins:
  - { reg: '$rdi', virtual-reg: '' }
  - { reg: '$esi', virtual-reg: '' }
  - { reg: '$rdx', virtual-reg: '' }
frameInfo:
  isCalleeSavedInfoValid: true
stack:
  - { id: 0, name: '', type: spill-slot, offset: -8, size: 8, alignment: 8,
      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: -16, size: 8, alignment: 8,
      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
body:             |
  bb.0:
    liveins: $esi, $rdi, $rdx, $r15, $r14, $r13, $r12, $r11, $rbx

    ; CHECK-LABEL: name: enabled
    ; CHECK: liveins: $esi, $rdi, $rdx, $r15, $r14, $r13, $r12, $r11, $rbx
    ; CHECK-NEXT: {{  $}}
    ; CHECK-NEXT: $rbx = MOV64rr $rdx
    ; CHECK-NEXT: $r14d = MOV32rr $esi
    ; CHECK-NEXT: $r15 = MOV64rr $rdi
    ; CHECK-NEXT: renamable $r12d = XOR32rr undef $r12d, undef $r12d, implicit-def dead $eflags, implicit-def $r12
    ; CHECK-NEXT: renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, implicit-def $rax

    ;; The store to the stack slot is still present.
    ; CHECK-NEXT: MOV64mr $rbp, 1, $noreg, -48, $noreg, killed renamable $rax :: (store (s64) into %stack.0)

    ; CHECK-NEXT: MOV64mr $rbp, 1, $noreg, -40, $noreg, killed renamable $r11 :: (store (s64) into %stack.1)
    ; CHECK-NEXT: renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags
    ; CHECK-NEXT: $r13d = MOV32rr killed $eax
    ; CHECK-NEXT: $rdi = MOV64rr $r15
    ; CHECK-NEXT: CALL64r renamable $r12, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit-def $rsp, implicit-def $ssp
    ; CHECK-NEXT: dead renamable $eax = MOV32rm renamable $rbx, 1, $noreg, 0, $noreg
    ; CHECK-NEXT: renamable $eax = MOV32ri 1
    ; CHECK-NEXT: TEST8ri renamable $r14b, 1, implicit-def $eflags
    
    ;; First FAKE_USE and its corresponding load are removed; second FAKE_USE of
    ;; a restored value that is also used is preserved.
    ; CHECK-NEXT: renamable $r11 = MOV64rm $rbp, 1, $noreg, -40, $noreg :: (load (s64) from %stack.1)
    ; CHECK-NEXT: renamable $r12d = XOR32rr $r12d, $r11d, implicit-def dead $eflags
    ; CHECK-NEXT: FAKE_USE killed renamable $r11d

    ; CHECK-NEXT: TEST32rr killed renamable $r13d, renamable $r13d, implicit-def $eflags
    ; CHECK-NEXT: RET64

    $rbx = MOV64rr $rdx
    $r14d = MOV32rr $esi
    $r15 = MOV64rr $rdi
    renamable $r12d = XOR32rr undef $r12d, undef $r12d, implicit-def dead $eflags, implicit-def $r12
    renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, implicit-def $rax
    MOV64mr $rbp, 1, $noreg, -48, $noreg, killed renamable $rax :: (store (s64) into %stack.0)
    MOV64mr $rbp, 1, $noreg, -40, $noreg, killed renamable $r11 :: (store (s64) into %stack.1)
    renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags
    $r13d = MOV32rr killed $eax
    $rdi = MOV64rr $r15
    CALL64r renamable $r12, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit-def $rsp, implicit-def $ssp
    dead renamable $eax = MOV32rm renamable $rbx, 1, $noreg, 0, $noreg
    renamable $eax = MOV32ri 1
    TEST8ri renamable $r14b, 1, implicit-def $eflags
    renamable $rax = MOV64rm $rbp, 1, $noreg, -48, $noreg :: (load (s64) from %stack.0)
    FAKE_USE renamable $eax, implicit killed $rax
    renamable $r11 = MOV64rm $rbp, 1, $noreg, -40, $noreg :: (load (s64) from %stack.1)
    renamable $r12d = XOR32rr $r12d, $r11d, implicit-def dead $eflags
    FAKE_USE killed renamable $r11d
    TEST32rr killed renamable $r13d, renamable $r13d, implicit-def $eflags
    RET64

...
---
name:            disabled
alignment:       16
tracksRegLiveness: true
noPhis:          true
noVRegs:         true
hasFakeUses:     true
tracksDebugUserValues: true
debugInstrRef: false
liveins:
  - { reg: '$rdi', virtual-reg: '' }
  - { reg: '$esi', virtual-reg: '' }
  - { reg: '$rdx', virtual-reg: '' }
frameInfo:
  isCalleeSavedInfoValid: true
stack:
  - { id: 0, name: '', type: spill-slot, offset: -8, size: 8, alignment: 8,
      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: -16, size: 8, alignment: 8,
      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
body:             |
  bb.0:
    liveins: $esi, $rdi, $rdx, $r15, $r14, $r13, $r12, $r11, $rbx

    ; CHECK-LABEL: name: disabled
    ; CHECK: liveins: $esi, $rdi, $rdx, $r15, $r14, $r13, $r12, $r11, $rbx
    ; CHECK-NEXT: {{  $}}
    ; CHECK-NEXT: $rbx = MOV64rr $rdx
    ; CHECK-NEXT: $r14d = MOV32rr $esi
    ; CHECK-NEXT: $r15 = MOV64rr $rdi
    ; CHECK-NEXT: renamable $r12d = XOR32rr undef $r12d, undef $r12d, implicit-def dead $eflags, implicit-def $r12
    ; CHECK-NEXT: renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, implicit-def $rax
    ; CHECK-NEXT: MOV64mr $rbp, 1, $noreg, -48, $noreg, killed renamable $rax :: (store (s64) into %stack.0)
    ; CHECK-NEXT: MOV64mr $rbp, 1, $noreg, -40, $noreg, killed renamable $r11 :: (store (s64) into %stack.1)
    ; CHECK-NEXT: renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags
    ; CHECK-NEXT: $r13d = MOV32rr killed $eax
    ; CHECK-NEXT: $rdi = MOV64rr $r15
    ; CHECK-NEXT: CALL64r renamable $r12, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit-def $rsp, implicit-def $ssp
    ; CHECK-NEXT: dead renamable $eax = MOV32rm renamable $rbx, 1, $noreg, 0, $noreg
    ; CHECK-NEXT: renamable $eax = MOV32ri 1
    ; CHECK-NEXT: TEST8ri renamable $r14b, 1, implicit-def $eflags

    ;; Verify that when instr-ref is disabled, we do not remove fake uses.
    ; CHECK-NEXT: renamable $rax = MOV64rm $rbp, 1, $noreg, -48, $noreg :: (load (s64) from %stack.0)
    ; CHECK-NEXT: FAKE_USE renamable $eax, implicit killed $rax
    ; CHECK-NEXT: renamable $r11 = MOV64rm $rbp, 1, $noreg, -40, $noreg :: (load (s64) from %stack.1)
    ; CHECK-NEXT: renamable $r12d = XOR32rr $r12d, $r11d, implicit-def dead $eflags
    ; CHECK-NEXT: FAKE_USE killed renamable $r11d
    ; CHECK-NEXT: TEST32rr killed renamable $r13d, renamable $r13d, implicit-def $eflags
    ; CHECK-NEXT: RET64
    $rbx = MOV64rr $rdx
    $r14d = MOV32rr $esi
    $r15 = MOV64rr $rdi
    renamable $r12d = XOR32rr undef $r12d, undef $r12d, implicit-def dead $eflags, implicit-def $r12
    renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, implicit-def $rax
    MOV64mr $rbp, 1, $noreg, -48, $noreg, killed renamable $rax :: (store (s64) into %stack.0)
    MOV64mr $rbp, 1, $noreg, -40, $noreg, killed renamable $r11 :: (store (s64) into %stack.1)
    renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags
    $r13d = MOV32rr killed $eax
    $rdi = MOV64rr $r15
    CALL64r renamable $r12, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit-def $rsp, implicit-def $ssp
    dead renamable $eax = MOV32rm renamable $rbx, 1, $noreg, 0, $noreg
    renamable $eax = MOV32ri 1
    TEST8ri renamable $r14b, 1, implicit-def $eflags
    renamable $rax = MOV64rm $rbp, 1, $noreg, -48, $noreg :: (load (s64) from %stack.0)
    FAKE_USE renamable $eax, implicit killed $rax
    renamable $r11 = MOV64rm $rbp, 1, $noreg, -40, $noreg :: (load (s64) from %stack.1)
    renamable $r12d = XOR32rr $r12d, $r11d, implicit-def dead $eflags
    FAKE_USE killed renamable $r11d
    TEST32rr killed renamable $r13d, renamable $r13d, implicit-def $eflags
    RET64

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