llvm/test/CodeGen/Generic/MachineBranchProb.ll

; RUN: llc < %s -print-machineinstrs=expand-isel-pseudos -o /dev/null 2>&1 | FileCheck %s

; ARM & AArch64 run an extra SimplifyCFG which disrupts this test.
; XFAIL: arm,aarch64

; Make sure we have the correct weight attached to each successor.
define i32 @test2(i32 %x) nounwind uwtable readnone ssp {
; CHECK-LABEL: Machine code for function test2:
entry:
  %conv = sext i32 %x to i64
  switch i64 %conv, label %return [
    i64 0, label %sw.bb
    i64 1, label %sw.bb
    i64 4, label %sw.bb
    i64 5, label %sw.bb1
  ], !prof !0
; CHECK: BB#0: derived from LLVM BB %entry
; CHECK: Successors according to CFG: BB#2(64) BB#4(14)
; CHECK: BB#4: derived from LLVM BB %entry
; CHECK: Successors according to CFG: BB#1(10) BB#5(4)
; CHECK: BB#5: derived from LLVM BB %entry
; CHECK: Successors according to CFG: BB#1(4) BB#3(7)

sw.bb:
  br label %return

sw.bb1:
  br label %return

return:
  %retval.0 = phi i32 [ 5, %sw.bb1 ], [ 1, %sw.bb ], [ 0, %entry ]
  ret i32 %retval.0
}

!0 = !{!"branch_weights", i32 7, i32 6, i32 4, i32 4, i32 64}


declare void @g(i32)
define void @left_leaning_weight_balanced_tree(i32 %x) {
entry:
  switch i32 %x, label %return [
    i32 0,  label %bb0
    i32 10, label %bb1
    i32 20, label %bb2
    i32 30, label %bb3
    i32 40, label %bb4
    i32 50, label %bb5
  ], !prof !1
bb0: tail call void @g(i32 0) br label %return
bb1: tail call void @g(i32 1) br label %return
bb2: tail call void @g(i32 2) br label %return
bb3: tail call void @g(i32 3) br label %return
bb4: tail call void @g(i32 4) br label %return
bb5: tail call void @g(i32 5) br label %return
return: ret void

; Check that we set branch weights on the pivot cmp instruction correctly.
; Cases {0,10,20,30} go on the left with weight 13; cases {40,50} go on the
; right with weight 20.
;
; CHECK-LABEL: Machine code for function left_leaning_weight_balanced_tree:
; CHECK: BB#0: derived from LLVM BB %entry
; CHECK-NOT: Successors
; CHECK: Successors according to CFG: BB#8(13) BB#9(20)
}

!1 = !{!"branch_weights",
  ; Default:
  i32 1,
  ; Case 0, 10, 20:
  i32 10, i32 1, i32 1,
  ; Case 30, 40, 50:
  i32 1, i32 10, i32 10}