test/CodeGen/X86/callbr-asm.ll

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=i686-- -O3 -verify-machineinstrs | FileCheck %s

; Tests for using callbr as an asm-goto wrapper

; Test 1 - fallthrough label gets removed, but the fallthrough code that is
; unreachable due to asm ending on a jmp is still left in.
define i32 @test1(i32 %a) {
; CHECK-LABEL: test1:
; CHECK:       # %bb.0: # %entry
; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT:    addl $4, %eax
; CHECK-NEXT:    #APP
; CHECK-NEXT:    xorl %eax, %eax
; CHECK-NEXT:    jmp .LBB0_2
; CHECK-NEXT:    #NO_APP
; CHECK-NEXT:  # %bb.1: # %normal
; CHECK-NEXT:    xorl %eax, %eax
; CHECK-NEXT:    retl
; CHECK-NEXT:  .LBB0_2: # Block address taken
; CHECK-NEXT:    # %fail
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:    movl $1, %eax
; CHECK-NEXT:    retl
entry:
  %0 = add i32 %a, 4
  callbr void asm "xorl $0, $0; jmp ${1:l}", "r,!i,~{dirflag},~{fpsr},~{flags}"(i32 %0) to label %normal [label %fail]

normal:
  ret i32 0

fail:
  ret i32 1
}

; Test 1b - Like test 1 but using `asm inteldialect`.
define i32 @test1b(i32 %a) {
; CHECK-LABEL: test1b:
; CHECK:       # %bb.0: # %entry
; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT:    addl $4, %eax
; CHECK-NEXT:    #APP
; CHECK-EMPTY:
; CHECK-NEXT:    xorl %eax, %eax
; CHECK-NEXT:    jmp .LBB1_2
; CHECK-EMPTY:
; CHECK-NEXT:    #NO_APP
; CHECK-NEXT:  # %bb.1: # %normal
; CHECK-NEXT:    xorl %eax, %eax
; CHECK-NEXT:    retl
; CHECK-NEXT:  .LBB1_2: # Block address taken
; CHECK-NEXT:    # %fail
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:    movl $1, %eax
; CHECK-NEXT:    retl
entry:
  %0 = add i32 %a, 4
  callbr void asm inteldialect "xor $0, $0; jmp ${1:l}", "r,!i,~{dirflag},~{fpsr},~{flags}"(i32 %0) to label %normal [label %fail]

normal:
  ret i32 0

fail:
  ret i32 1
}

; Test 2 - callbr terminates an unreachable block, function gets simplified
; to a trivial zero return.
define i32 @test2(i32 %a) {
; CHECK-LABEL: test2:
; CHECK:       # %bb.0: # %entry
; CHECK-NEXT:    xorl %eax, %eax
; CHECK-NEXT:    retl
entry:
  br label %normal

unreachableasm:
  %0 = add i32 %a, 4
  callbr void asm sideeffect "xorl $0, $0; jmp ${1:l}", "r,!i,~{dirflag},~{fpsr},~{flags}"(i32 %0) to label %normal [label %fail]

normal:
  ret i32 0

fail:
  ret i32 1
}

; Test 3 - asm-goto implements a loop. The loop gets recognized, but many loop
; transforms fail due to canonicalization having callbr exceptions. Trivial
; blocks at labels 1 and 3 also don't get simplified due to callbr.
define i32 @test3(i32 %a) {
; CHECK-LABEL: test3:
; CHECK:       # %bb.0: # %entry
; CHECK-NEXT:  .LBB3_1: # Block address taken
; CHECK-NEXT:    # %label01
; CHECK-NEXT:    # =>This Loop Header: Depth=1
; CHECK-NEXT:    # Child Loop BB3_2 Depth 2
; CHECK-NEXT:    # Child Loop BB3_3 Depth 3
; CHECK-NEXT:    # Child Loop BB3_4 Depth 4
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:  .LBB3_2: # Block address taken
; CHECK-NEXT:    # %label02
; CHECK-NEXT:    # Parent Loop BB3_1 Depth=1
; CHECK-NEXT:    # => This Loop Header: Depth=2
; CHECK-NEXT:    # Child Loop BB3_3 Depth 3
; CHECK-NEXT:    # Child Loop BB3_4 Depth 4
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:    addl $4, {{[0-9]+}}(%esp)
; CHECK-NEXT:  .LBB3_3: # Block address taken
; CHECK-NEXT:    # %label03
; CHECK-NEXT:    # Parent Loop BB3_1 Depth=1
; CHECK-NEXT:    # Parent Loop BB3_2 Depth=2
; CHECK-NEXT:    # => This Loop Header: Depth=3
; CHECK-NEXT:    # Child Loop BB3_4 Depth 4
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:  .LBB3_4: # Block address taken
; CHECK-NEXT:    # %label04
; CHECK-NEXT:    # Parent Loop BB3_1 Depth=1
; CHECK-NEXT:    # Parent Loop BB3_2 Depth=2
; CHECK-NEXT:    # Parent Loop BB3_3 Depth=3
; CHECK-NEXT:    # => This Inner Loop Header: Depth=4
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:    #APP
; CHECK-NEXT:    jmp .LBB3_1
; CHECK-NEXT:    jmp .LBB3_2
; CHECK-NEXT:    jmp .LBB3_3
; CHECK-NEXT:    #NO_APP
; CHECK-NEXT:  # %bb.5: # %normal0
; CHECK-NEXT:    # in Loop: Header=BB3_4 Depth=4
; CHECK-NEXT:    #APP
; CHECK-NEXT:    jmp .LBB3_1
; CHECK-NEXT:    jmp .LBB3_2
; CHECK-NEXT:    jmp .LBB3_3
; CHECK-NEXT:    jmp .LBB3_4
; CHECK-NEXT:    #NO_APP
; CHECK-NEXT:  # %bb.6: # %normal1
; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT:    retl
entry:
  %a.addr = alloca i32, align 4
  store i32 %a, ptr %a.addr, align 4
  br label %label01

label01:                                          ; preds = %normal0, %label04, %entry
  br label %label02

label02:                                          ; preds = %normal0, %label04, %label01
  %0 = load i32, ptr %a.addr, align 4
  %add = add nsw i32 %0, 4
  store i32 %add, ptr %a.addr, align 4
  br label %label03

label03:                                          ; preds = %normal0, %label04, %label02
  br label %label04

label04:                                          ; preds = %normal0, %label03
  callbr void asm sideeffect "jmp ${0:l}; jmp ${1:l}; jmp ${2:l}", "!i,!i,!i,~{dirflag},~{fpsr},~{flags}"()
          to label %normal0 [label %label01, label %label02, label %label03]

normal0:                                          ; preds = %label04
  callbr void asm sideeffect "jmp ${0:l}; jmp ${1:l}; jmp ${2:l}; jmp ${3:l}", "!i,!i,!i,!i,~{dirflag},~{fpsr},~{flags}"()
          to label %normal1 [label %label01, label %label02, label %label03, label %label04]

normal1:                                          ; preds = %normal0
  %1 = load i32, ptr %a.addr, align 4
  ret i32 %1
}

; Test 4 - asm-goto referenced with the 'l' (ell) modifier and not.
define void @test4() {
; CHECK-LABEL: test4:
; CHECK:       # %bb.0: # %entry
; CHECK-NEXT:    #APP
; CHECK-NEXT:    ja .LBB4_3
; CHECK-NEXT:    #NO_APP
; CHECK-NEXT:  # %bb.1: # %asm.fallthrough
; CHECK-NEXT:    #APP
; CHECK-NEXT:    ja .LBB4_3
; CHECK-NEXT:    #NO_APP
; CHECK-NEXT:  .LBB4_3: # Block address taken
; CHECK-NEXT:    # %quux
; CHECK-NEXT:    # Label of block must be emitted
; CHECK-NEXT:    retl
entry:
  callbr void asm sideeffect "ja $0", "!i,~{dirflag},~{fpsr},~{flags}"()
          to label %asm.fallthrough [label %quux]

asm.fallthrough:                                  ; preds = %entry
  callbr void asm sideeffect "ja ${0:l}", "!i,~{dirflag},~{fpsr},~{flags}"()
          to label %cleanup [label %quux]

quux:                                             ; preds = %asm.fallthrough, %entry
  br label %cleanup

cleanup:                                          ; preds = %asm.fallthrough, %quux
  ret void
}