test/CodeGen/Mips/compactbranches/empty-block.mir

# RUN: llc -march=mipsel -mcpu=mips32r6 -start-after=block-placement %s -o - | FileCheck %s

# Check that empty blocks in the cfg don't cause the mips hazard scheduler to
# crash and that the nop is inserted correctly.

# CHECK:  blezc
# CHECK:  nop
# CHECK: # BB#1:
# CHECK:  .insn
# CHECK: # BB#2:
# CHECK:  .insn
# CHECK: # BB#3:
# CHECK:  jal

--- |
  ; ModuleID = '<stdin>'
  source_filename = "<stdin>"
  target datalayout = "e-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64"

  declare i32 @k()

  declare void @f(i32)

  define void @l5() {
  entry:
    %call = tail call i32 @k()
    %cmp = icmp sgt i32 %call, 0
    br i1 %cmp, label %if.then, label %if.end

  if.then:                                          ; preds = %entry
    tail call void @f(i32 signext 2)
    br label %if.end

  if.end:                                           ; preds = %if.then, %entry
    ret void
  }

---
name:            l5
alignment:       2
exposesReturnsTwice: false
legalized:       false
regBankSelected: false
selected:        false
tracksRegLiveness: true
frameInfo:
  isFrameAddressTaken: false
  isReturnAddressTaken: false
  hasStackMap:     false
  hasPatchPoint:   false
  stackSize:       24
  offsetAdjustment: 0
  maxAlignment:    4
  adjustsStack:    true
  hasCalls:        true
  maxCallFrameSize: 16
  hasOpaqueSPAdjustment: false
  hasVAStart:      false
  hasMustTailInVarArgFunc: false
stack:
  - { id: 0, type: spill-slot, offset: -4, size: 4, alignment: 4, callee-saved-register: '%ra' }
body:             |
  bb.0.entry:
    successors: %bb.1.if.then(0x50000000), %bb.4.if.end(0x30000000)
    liveins: %ra

    %sp = ADDiu %sp, -24
    CFI_INSTRUCTION def_cfa_offset 24
    SW killed %ra, %sp, 20 :: (store 4 into %stack.0)
    CFI_INSTRUCTION offset %ra_64, -4
    JAL @k, csr_o32_fp64, implicit-def dead %ra, implicit-def %sp, implicit-def %v0
    BLEZ %v0, %bb.4.if.end, implicit-def %at

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

  bb.2.if.then:
    successors: %bb.3.if.then(0x80000000)

  bb.3.if.then:
    successors: %bb.4.if.end(0x80000000)

    %a0 = ADDiu %zero, 2
    JAL @f, csr_o32_fp64, implicit-def dead %ra, implicit killed %a0, implicit-def %sp

  bb.4.if.end:
    %ra = LW %sp, 20 :: (load 4 from %stack.0)
    %sp = ADDiu %sp, 24
    PseudoReturn undef %ra

...