machine-outliner-bad-register.mir 4.36 KB
# RUN: llc -mtriple=aarch64--- -run-pass=machine-outliner \
# RUN: -verify-machineinstrs %s -o - | FileCheck %s

# Ensure that we don't outline from regions where x16, x17, or nzcv are live
# across the outlining candidate. These values are allowed to be clobbered by,
# say, the linker, in the presence of function calls. Thus, we can't outline
# these, since the insertion of the outlined call could change the values of
# these registers.
--- |
  ; No problematic register appears at all. Safe for outlining.
  define void @reg_never_defined() #0 { ret void }

  ; A problematic register is live, but after the candidate. Safe for outlining.
  define void @reg_defined_after_candidate() #0 { ret void }

  ; A problematic register is live before the candidate, but killed before
  ; entry to the candidate. Safe for outlining.
  define void @reg_killed_before_candidate() #0 { ret void }

  ; Ensure that we never outline when any of the problematic registers we care
  ; about are defined across the outlining candidate.
  define void @x16_live() #0 { ret void }
  define void @x17_live() #0 { ret void }
  define void @nzcv_live() #0 { ret void }

  ; Test a combination of the above behaviours.
  ; [candidate] (1)
  ; - define a bad register -
  ; [candidate] (2)
  ; - kill the bad register -
  ; [candidate] (3)
  ;
  ; (1) and (3) should be outlined, while (2) should not be outlined.
  define void @multiple_ranges() #0 { ret void }

  attributes #0 = { noredzone }
...
---

# There should be two calls to outlined functions here, since we haven't tripped
# any of the cases above.
name:           reg_never_defined
tracksRegLiveness: true
body:             |
  bb.0:
    ; CHECK-LABEL: bb.0:
    ; CHECK: BL
    liveins: $w8, $wzr
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
  bb.1:
    ; CHECK-LABEL: bb.1:
    ; CHECK: BL
    liveins: $w8, $wzr
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
  bb.2:
    RET undef $lr
...
---

name:            reg_defined_after_candidate
tracksRegLiveness: true
body:             |
  bb.0:
    ; CHECK-LABEL: bb.0:
    ; CHECK: BL
    ; CHECK-NEXT: $x16 = ORRXri $x8, 5, implicit-def $x16, implicit-def $w16
    liveins: $w8, $wzr
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
    $x16 = ORRXri $x8, 5, implicit-def $x16, implicit-def $w16
    $w8 = ORRWri $w16, 5
    RET undef $lr
...
---

name:            reg_killed_before_candidate
tracksRegLiveness: true
body:             |
  bb.0:
    ; CHECK-LABEL: bb.0:
    ; CHECK: BL
    liveins: $w8, $wzr, $x16
    dead $x16 = ORRXri $x8, 6
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
    RET undef $lr
...
---

name:            x16_live
tracksRegLiveness: true
body:             |
  bb.0:
    ; CHECK-LABEL: bb.0:
    ; CHECK-NOT: BL
    liveins: $w8, $wzr, $x16
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
  bb.1:
    liveins: $x16
    RET undef $lr
...
---

name:            x17_live
tracksRegLiveness: true
body:             |
  bb.0:
    ; CHECK-LABEL: bb.0:
    ; CHECK-NOT: BL
    liveins: $w8, $wzr, $x17
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
    $w8 = ORRWri $w17, 5
    RET undef $lr
...
---

name:            nzcv_live
tracksRegLiveness: true
body:             |
  bb.0:
    liveins: $w8, $wzr, $nzcv
    ; CHECK-LABEL: bb.0:
    ; CHECK-NOT: BL
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
  bb.1:
    liveins: $nzcv
    RET undef $lr
...
---

name:            multiple_ranges
tracksRegLiveness: true
body:             |
  bb.0:
    ; CHECK-LABEL: bb.0:
    ; CHECK: BL
    liveins: $w8, $wzr
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
    $x16 = ORRXri $x8, 5, implicit-def $x16
  bb.1:
    ; CHECK-LABEL: bb.1:
    ; CHECK-NOT: BL
    liveins: $w8, $x16
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
  bb.2:
    ; CHECK-LABEL: bb.2:
    ; CHECK: BL
    liveins: $w8, $x16
    dead $x16 = ORRXri $x8, 0
    $w8 = ORRWri $wzr, 1
    $w8 = ORRWri $wzr, 2
    $w8 = ORRWri $wzr, 3
    $w8 = ORRWri $wzr, 4
  bb.3:
    liveins: $w8
    RET undef $lr
...
---