test/Transforms/TailCallElim/entry-count-adjustment.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
; RUN: opt -passes=tailcallelim -S %s -o - | FileCheck %s --check-prefixes=CHECK,ENABLED
; RUN: opt -passes=tailcallelim -tre-disable-entrycount-recompute -S %s -o - | FileCheck %s --check-prefixes=CHECK,DISABLED

; Test that tail call elimination correctly adjusts function entry counts
; when eliminating tail recursive calls.

; Basic test: eliminate a tail call and adjust entry count
define i32 @test_basic_entry_count_adjustment(i32 %n) !prof !0 {
; CHECK-LABEL: @test_basic_entry_count_adjustment(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[TAILRECURSE:%.*]]
; CHECK:       tailrecurse:
; CHECK-NEXT:    [[N_TR:%.*]] = phi i32 [ [[N:%.*]], [[ENTRY:%.*]] ], [ [[SUB:%.*]], [[IF_THEN:%.*]] ]
; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[N_TR]], 0
; CHECK-NEXT:    br i1 [[CMP]], label [[IF_THEN]], label [[IF_ELSE:%.*]], !prof [[PROF1:![0-9]+]]
; CHECK:       if.then:
; CHECK-NEXT:    [[SUB]] = sub i32 [[N_TR]], 1
; CHECK-NEXT:    br label [[TAILRECURSE]]
; CHECK:       if.else:
; CHECK-NEXT:    ret i32 0
;
entry:
  %cmp = icmp sgt i32 %n, 0
  br i1 %cmp, label %if.then, label %if.else, !prof !1

if.then:                                          ; preds = %entry
  %sub = sub i32 %n, 1
  %call = tail call i32 @test_basic_entry_count_adjustment(i32 %sub)
  ret i32 %call

if.else:                                          ; preds = %entry
  ret i32 0
}

; Test multiple tail calls in different blocks with different frequencies
define i32 @test_multiple_blocks_entry_count(i32 %n, i32 %flag) !prof !2 {
; CHECK-LABEL: @test_multiple_blocks_entry_count(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[TAILRECURSE:%.*]]
; CHECK:       tailrecurse:
; CHECK-NEXT:    [[N_TR:%.*]] = phi i32 [ [[N:%.*]], [[ENTRY:%.*]] ], [ [[SUB1:%.*]], [[BLOCK1:%.*]] ], [ [[SUB2:%.*]], [[BLOCK2:%.*]] ]
; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[N_TR]], 0
; CHECK-NEXT:    br i1 [[CMP]], label [[CHECK_FLAG:%.*]], label [[BASE_CASE:%.*]], !prof [[PROF3:![0-9]+]]
; CHECK:       check.flag:
; CHECK-NEXT:    [[CMP_FLAG:%.*]] = icmp eq i32 [[FLAG:%.*]], 1
; CHECK-NEXT:    br i1 [[CMP_FLAG]], label [[BLOCK1]], label [[BLOCK2]], !prof [[PROF4:![0-9]+]]
; CHECK:       block1:
; CHECK-NEXT:    [[SUB1]] = sub i32 [[N_TR]], 1
; CHECK-NEXT:    br label [[TAILRECURSE]]
; CHECK:       block2:
; CHECK-NEXT:    [[SUB2]] = sub i32 [[N_TR]], 2
; CHECK-NEXT:    br label [[TAILRECURSE]]
; CHECK:       base.case:
; CHECK-NEXT:    ret i32 1
;
entry:
  %cmp = icmp sgt i32 %n, 0
  br i1 %cmp, label %check.flag, label %base.case, !prof !3
check.flag:
  %cmp.flag = icmp eq i32 %flag, 1
  br i1 %cmp.flag, label %block1, label %block2, !prof !4
block1:                                           ; preds = %check.flag
  %sub1 = sub i32 %n, 1
  %call1 = tail call i32 @test_multiple_blocks_entry_count(i32 %sub1, i32 %flag)
  ret i32 %call1
block2:                                           ; preds = %check.flag
  %sub2 = sub i32 %n, 2
  %call2 = tail call i32 @test_multiple_blocks_entry_count(i32 %sub2, i32 %flag)
  ret i32 %call2
base.case:                                        ; preds = %entry
  ret i32 1
}

define i32 @test_no_entry_count(i32 %n) {
; CHECK-LABEL: @test_no_entry_count(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[TAILRECURSE:%.*]]
; CHECK:       tailrecurse:
; CHECK-NEXT:    [[N_TR:%.*]] = phi i32 [ [[N:%.*]], [[ENTRY:%.*]] ], [ [[SUB:%.*]], [[IF_THEN:%.*]] ]
; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[N_TR]], 0
; CHECK-NEXT:    br i1 [[CMP]], label [[IF_THEN]], label [[IF_ELSE:%.*]]
; CHECK:       if.then:
; CHECK-NEXT:    [[SUB]] = sub i32 [[N_TR]], 1
; CHECK-NEXT:    br label [[TAILRECURSE]]
; CHECK:       if.else:
; CHECK-NEXT:    ret i32 0
;
entry:
  %cmp = icmp sgt i32 %n, 0
  br i1 %cmp, label %if.then, label %if.else

if.then:                                          ; preds = %entry
  %sub = sub i32 %n, 1
  %call = tail call i32 @test_no_entry_count(i32 %sub)
  ret i32 %call

if.else:                                          ; preds = %entry
  ret i32 0
}

; Function entry count metadata
!0 = !{!"function_entry_count", i64 1000}
!1 = !{!"branch_weights", i32 800, i32 200}
!2 = !{!"function_entry_count", i64 2000}
!3 = !{!"branch_weights", i32 3, i32 1}
!4 = !{!"branch_weights", i32 100, i32 900}
;.
; ENABLED: [[META0:![0-9]+]] = !{!"function_entry_count", i64 200}
; ENABLED: [[PROF1]] = !{!"branch_weights", i32 800, i32 200}
; ENABLED: [[META2:![0-9]+]] = !{!"function_entry_count", i64 500}
; ENABLED: [[PROF3]] = !{!"branch_weights", i32 3, i32 1}
; ENABLED: [[PROF4]] = !{!"branch_weights", i32 100, i32 900}
;.
; DISABLED: [[META0:![0-9]+]] = !{!"function_entry_count", i64 1000}
; DISABLED: [[PROF1]] = !{!"branch_weights", i32 800, i32 200}
; DISABLED: [[META2:![0-9]+]] = !{!"function_entry_count", i64 2000}
; DISABLED: [[PROF3]] = !{!"branch_weights", i32 3, i32 1}
; DISABLED: [[PROF4]] = !{!"branch_weights", i32 100, i32 900}
;.