File: block-placement-optimize-branches.ll

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llvm-toolchain-20 1%3A20.1.6-1~exp1
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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc < %s -mtriple=aarch64 | FileCheck %s

; When consuming profile data we sometimes flip a branch to improve runtime
; performance. If we are optimizing for size, we avoid changing the branch to
; improve outlining and ICF.

define i8 @foo_optsize(i32 %v4) optsize {
; CHECK-LABEL: foo_optsize:
; CHECK:       // %bb.0: // %entry
; CHECK-NEXT:    cbz wzr, .LBB0_2
; CHECK-NEXT:  .LBB0_1:
; CHECK-NEXT:    mov w0, wzr
; CHECK-NEXT:    ret
; CHECK-NEXT:  .LBB0_2: // %b1
; CHECK-NEXT:    cbnz w0, .LBB0_4
; CHECK-NEXT:  .LBB0_3: // %b2
; CHECK-NEXT:    mov w0, #1 // =0x1
; CHECK-NEXT:    ret
; CHECK-NEXT:  .LBB0_4: // %b1
; CHECK-NEXT:    cmp w0, #1
; CHECK-NEXT:    b.ne .LBB0_1
; CHECK-NEXT:  // %bb.5: // %b3
; CHECK-NEXT:    cbz wzr, .LBB0_1
; CHECK-NEXT:    b .LBB0_3
entry:
  %v2 = icmp eq i32 0, 0
  br i1 %v2, label %b1, label %b4

b1:
  switch i32 %v4, label %b4 [
    i32 1, label %b3
    i32 0, label %b2
  ], !prof !0

b2:
  br label %b4

b3:
  %v3 = icmp eq i32 0, 0
  br i1 %v3, label %b4, label %b2

b4:
  %v16 = phi i8 [ 1, %b2 ], [ 0, %entry ], [ 0, %b3 ], [ 0, %b1 ]
  ret i8 %v16
}

define i8 @foo_optspeed(i32 %v4) {
; CHECK-LABEL: foo_optspeed:
; CHECK:       // %bb.0: // %entry
; CHECK-NEXT:    cbz wzr, .LBB1_2
; CHECK-NEXT:  .LBB1_1:
; CHECK-NEXT:    mov w0, wzr
; CHECK-NEXT:    ret
; CHECK-NEXT:  .LBB1_2: // %b1
; CHECK-NEXT:    cbnz w0, .LBB1_4
; CHECK-NEXT:  .LBB1_3: // %b2
; CHECK-NEXT:    mov w0, #1 // =0x1
; CHECK-NEXT:    ret
; CHECK-NEXT:  .LBB1_4: // %b1
; CHECK-NEXT:    cmp w0, #1
; CHECK-NEXT:    b.ne .LBB1_1
; CHECK-NEXT:  // %bb.5: // %b3
; CHECK-NEXT:    cbnz wzr, .LBB1_3
; CHECK-NEXT:    b .LBB1_1
entry:
  %v2 = icmp eq i32 0, 0
  br i1 %v2, label %b1, label %b4

b1:
  switch i32 %v4, label %b4 [
    i32 1, label %b3
    i32 0, label %b2
  ], !prof !0

b2:
  br label %b4

b3:
  %v3 = icmp eq i32 0, 0
  br i1 %v3, label %b4, label %b2

b4:
  %v16 = phi i8 [ 1, %b2 ], [ 0, %entry ], [ 0, %b3 ], [ 0, %b1 ]
  ret i8 %v16
}

!0 = !{!"branch_weights", i32 5, i32 5, i32 100}