llvm/llvm/test/CodeGen/Thumb/machine-cse-deadreg.mir

# RUN: llc -mtriple thumbv6m-arm-none-eabi -run-pass=machine-cse -verify-machineinstrs -o - %s | FileCheck %s
# RUN: llc -mtriple thumbv6m-arm-none-eabi -passes=machine-cse -o - %s | FileCheck %s

--- |
  target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
  target triple = "thumbv6m-arm-none-eabi"

  define i32 @funca(i64 %l1) {
  entry:
    %l2 = icmp ult i64 %l1, -177673816660004267
    %l3 = add i64 %l1, 401100203
    %rem.i = select i1 %l2, i64 %l1, i64 %l3
    %conv = trunc i64 %rem.i to i32
    ret i32 %conv
  }

  define i32 @funcb(i64 %l1) { ret i32 0 }

...
---
name:            funca
tracksRegLiveness: true
liveins:
  - { reg: '$r0', virtual-reg: '%0' }
  - { reg: '$r1', virtual-reg: '%1' }
constants:
  - id:              0
    value:           i32 401100203
    alignment:       4
    isTargetSpecific: false
  - id:              1
    value:           i32 41367909
    alignment:       4
    isTargetSpecific: false
body:             |
  bb.0.entry:
    successors: %bb.1(0x40000000), %bb.2(0x40000000)
    liveins: $r0, $r1

    %1:tgpr = COPY $r1
    %0:tgpr = COPY $r0
    %2:tgpr = tLDRpci %const.0, 14, $noreg :: (load (s32) from constant-pool)
    %3:tgpr, dead $cpsr = tADDrr %0, %2, 14, $noreg
    %4:tgpr = tLDRpci %const.1, 14, $noreg :: (load (s32) from constant-pool)
    %5:tgpr, $cpsr = tADDrr %0, %2, 14, $noreg
    %6:tgpr, $cpsr = tADC %1, killed %4, 14, $noreg, implicit $cpsr
    tBcc %bb.2, 3, $cpsr

  bb.1.entry:
    successors: %bb.2(0x80000000)

  bb.2.entry:
    %7:tgpr = PHI %3, %bb.1, %0, %bb.0
    $r0 = COPY %7
    tBX_RET 14, $noreg, implicit $r0

# CHECK-LABEL: name: funca
# cpsr def must not be dead
# CHECK: %3:tgpr, $cpsr = tADDrr %0, %2
# CHECK-NOT: %5:tgpr, $cpsr = tADDrr %0, %2

...
---
name:            funcb
tracksRegLiveness: true
liveins:
  - { reg: '$r0', virtual-reg: '%0' }
  - { reg: '$r1', virtual-reg: '%1' }
constants:
  - id:              0
    value:           i32 401100203
    alignment:       4
    isTargetSpecific: false
  - id:              1
    value:           i32 41367909
    alignment:       4
    isTargetSpecific: false
body:             |
  bb.0:
    successors: %bb.1(0x40000000), %bb.2(0x40000000)
    liveins: $r0, $r1

    %1:tgpr = COPY $r1
    %0:tgpr = COPY $r0
    %2:tgpr = tLDRpci %const.0, 14, $noreg :: (load (s32) from constant-pool)
    %3:tgpr, dead $cpsr = tADDrr %0, %2, 14, $noreg
    %4:tgpr = tLDRpci %const.1, 14, $noreg :: (load (s32) from constant-pool)
    %5:tgpr, dead $cpsr = tADDrr %0, %2, 14, $noreg
    %6:tgpr, $cpsr = tADDrr %1, killed %4, 14, $noreg
    tBcc %bb.2, 3, $cpsr

  bb.1:
    successors: %bb.2(0x80000000)

  bb.2:
    %7:tgpr = PHI %3, %bb.1, %0, %bb.0
    $r0 = COPY %7
    tBX_RET 14, $noreg, implicit $r0

# CHECK-LABEL: name: funcb
# cpsr def should be dead
# CHECK: %3:tgpr, dead $cpsr = tADDrr %0, %2
# CHECK-NOT: %5:tgpr, dead $cpsr = tADDrr %0, %2
...