xref: /llvm-project-15.0.7/llvm/test/Transforms/IndVarSimplify/loop-predication.ll (revision c8b675ea)

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -indvars -indvars-predicate-loops=1 -S | FileCheck %s

declare void @prevent_merging()

; Base case
define i32 @test1(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @test1(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[N:%.*]], i32 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i32 [[TMP0]]
; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[TMP1]], i32 [[LENGTH:%.*]])
; CHECK-NEXT:    [[TMP2:%.*]] = icmp ne i32 [[LENGTH]], [[UMIN]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP2]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0:![0-9]+]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

; Has side effect which must be reflected
define i32 @neg_store(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @neg_store(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH:%.*]]
; CHECK-NEXT:    br i1 [[WITHIN_BOUNDS]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    store i32 0, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  store i32 0, i32* %array.i.ptr
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

declare void @maythrow()

; May exit through implicit exception edge
define i32 @neg_implicit_exit(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @neg_implicit_exit(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    call void @maythrow()
; CHECK-NEXT:    [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH:%.*]]
; CHECK-NEXT:    br i1 [[WITHIN_BOUNDS]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  call void @maythrow()
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}



; Base case, but in LFTR form (just for basic correctness checking)
define i32 @test2(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @test2(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[N:%.*]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i32 [[TMP0]]
; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[TMP1]], i32 [[LENGTH:%.*]])
; CHECK-NEXT:    [[TMP2:%.*]] = icmp ne i32 [[LENGTH]], [[UMIN]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP2]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ne i32 [[I_NEXT]], [[N]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %within.bounds = icmp ne i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ne i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

; br (and rcheck1, rcheck2)
define i32 @two_range_checks(i32* %array.1, i32 %length.1, i32* %array.2, i32 %length.2, i32 %n) {
; CHECK-LABEL: @two_range_checks(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[LENGTH_2:%.*]], i32 [[LENGTH_1:%.*]])
; CHECK-NEXT:    [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[N:%.*]], i32 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i32 [[TMP0]]
; CHECK-NEXT:    [[UMIN1:%.*]] = call i32 @llvm.umin.i32(i32 [[TMP1]], i32 [[UMIN]])
; CHECK-NEXT:    [[TMP2:%.*]] = icmp ne i32 [[UMIN]], [[UMIN1]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP2]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_1_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_1:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_1_I:%.*]] = load i32, i32* [[ARRAY_1_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_1:%.*]] = add i32 [[LOOP_ACC]], [[ARRAY_1_I]]
; CHECK-NEXT:    [[ARRAY_2_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_2:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_2_I:%.*]] = load i32, i32* [[ARRAY_2_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC_1]], [[ARRAY_2_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %within.bounds.1 = icmp ult i32 %i, %length.1
  %within.bounds.2 = icmp ult i32 %i, %length.2
  %within.bounds = and i1 %within.bounds.1, %within.bounds.2
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
  %array.1.i = load i32, i32* %array.1.i.ptr, align 4
  %loop.acc.1 = add i32 %loop.acc, %array.1.i
  %array.2.i.ptr = getelementptr inbounds i32, i32* %array.2, i64 %i.i64
  %array.2.i = load i32, i32* %array.2.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc.1, %array.2.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

define i32 @three_range_checks(i32* %array.1, i32 %length.1, i32* %array.2, i32 %length.2, i32* %array.3, i32 %length.3, i32 %n) {
; CHECK-LABEL: @three_range_checks(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[LENGTH_3:%.*]], i32 [[LENGTH_2:%.*]])
; CHECK-NEXT:    [[UMIN1:%.*]] = call i32 @llvm.umin.i32(i32 [[UMIN]], i32 [[LENGTH_1:%.*]])
; CHECK-NEXT:    [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[N:%.*]], i32 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i32 [[TMP0]]
; CHECK-NEXT:    [[UMIN2:%.*]] = call i32 @llvm.umin.i32(i32 [[TMP1]], i32 [[UMIN1]])
; CHECK-NEXT:    [[TMP2:%.*]] = icmp ne i32 [[UMIN1]], [[UMIN2]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP2]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_1_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_1:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_1_I:%.*]] = load i32, i32* [[ARRAY_1_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_1:%.*]] = add i32 [[LOOP_ACC]], [[ARRAY_1_I]]
; CHECK-NEXT:    [[ARRAY_2_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_2:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_2_I:%.*]] = load i32, i32* [[ARRAY_2_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_2:%.*]] = add i32 [[LOOP_ACC_1]], [[ARRAY_2_I]]
; CHECK-NEXT:    [[ARRAY_3_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_3:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_3_I:%.*]] = load i32, i32* [[ARRAY_3_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC_2]], [[ARRAY_3_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %within.bounds.1 = icmp ult i32 %i, %length.1
  %within.bounds.2 = icmp ult i32 %i, %length.2
  %within.bounds.3 = icmp ult i32 %i, %length.3
  %within.bounds.1.and.2 = and i1 %within.bounds.1, %within.bounds.2
  %within.bounds = and i1 %within.bounds.1.and.2, %within.bounds.3
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
  %array.1.i = load i32, i32* %array.1.i.ptr, align 4
  %loop.acc.1 = add i32 %loop.acc, %array.1.i
  %array.2.i.ptr = getelementptr inbounds i32, i32* %array.2, i64 %i.i64
  %array.2.i = load i32, i32* %array.2.i.ptr, align 4
  %loop.acc.2 = add i32 %loop.acc.1, %array.2.i
  %array.3.i.ptr = getelementptr inbounds i32, i32* %array.3, i64 %i.i64
  %array.3.i = load i32, i32* %array.3.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc.2, %array.3.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

; Analogous to the above, but with two distinct branches (on different conditions)
define i32 @distinct_checks(i32* %array.1, i32 %length.1, i32* %array.2, i32 %length.2, i32* %array.3, i32 %length.3, i32 %n) {
; CHECK-LABEL: @distinct_checks(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[N:%.*]], i32 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i32 [[TMP0]]
; CHECK-NEXT:    [[TMP2:%.*]] = freeze i32 [[LENGTH_2:%.*]]
; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[TMP1]], i32 [[TMP2]])
; CHECK-NEXT:    [[UMIN1:%.*]] = call i32 @llvm.umin.i32(i32 [[UMIN]], i32 [[LENGTH_1:%.*]])
; CHECK-NEXT:    [[TMP3:%.*]] = icmp ne i32 [[LENGTH_1]], [[UMIN1]]
; CHECK-NEXT:    [[TMP4:%.*]] = icmp ne i32 [[LENGTH_2]], [[UMIN1]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED1:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED1]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP3]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_1_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_1:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_1_I:%.*]] = load i32, i32* [[ARRAY_1_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_1:%.*]] = add i32 [[LOOP_ACC]], [[ARRAY_1_I]]
; CHECK-NEXT:    br i1 [[TMP4]], label [[GUARDED1]], label [[DEOPT2:%.*]], !prof [[PROF0]]
; CHECK:       deopt2:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded1:
; CHECK-NEXT:    [[ARRAY_3_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_3:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_3_I:%.*]] = load i32, i32* [[ARRAY_3_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC_1]], [[ARRAY_3_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED1]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded4, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded1 ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded1 ], [ 0, %loop.preheader ]
  %within.bounds.1 = icmp ult i32 %i, %length.1
  br i1 %within.bounds.1, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
  %array.1.i = load i32, i32* %array.1.i.ptr, align 4
  %loop.acc.1 = add i32 %loop.acc, %array.1.i
  %within.bounds.2 = icmp ult i32 %i, %length.2
  br i1 %within.bounds.2, label %guarded1, label %deopt2, !prof !0

deopt2:                                           ; preds = %guarded
  call void @prevent_merging()
  ret i32 -1

guarded1:                                         ; preds = %guarded1
  %array.3.i.ptr = getelementptr inbounds i32, i32* %array.3, i64 %i.i64
  %array.3.i = load i32, i32* %array.3.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc.1, %array.3.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:
  %result = phi i32 [ %loop.acc.next, %guarded1 ]
  ret i32 %result
}

define i32 @duplicate_checks(i32* %array.1, i32* %array.2, i32* %array.3, i32 %length, i32 %n) {
; CHECK-LABEL: @duplicate_checks(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[N:%.*]], i32 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[UMAX]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i32 [[TMP0]]
; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[TMP1]], i32 [[LENGTH:%.*]])
; CHECK-NEXT:    [[TMP2:%.*]] = icmp ne i32 [[LENGTH]], [[UMIN]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED1:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED1]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP2]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_1_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_1:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_1_I:%.*]] = load i32, i32* [[ARRAY_1_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_1:%.*]] = add i32 [[LOOP_ACC]], [[ARRAY_1_I]]
; CHECK-NEXT:    br i1 true, label [[GUARDED1]], label [[DEOPT2:%.*]], !prof [[PROF0]]
; CHECK:       deopt2:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded1:
; CHECK-NEXT:    [[ARRAY_3_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY_3:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_3_I:%.*]] = load i32, i32* [[ARRAY_3_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC_1]], [[ARRAY_3_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED1]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded4, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded1 ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded1 ], [ 0, %loop.preheader ]
  %within.bounds.1 = icmp ult i32 %i, %length
  br i1 %within.bounds.1, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
  %array.1.i = load i32, i32* %array.1.i.ptr, align 4
  %loop.acc.1 = add i32 %loop.acc, %array.1.i
  %within.bounds.2 = icmp ult i32 %i, %length
  br i1 %within.bounds.2, label %guarded1, label %deopt2, !prof !0

deopt2:                                           ; preds = %guarded
  call void @prevent_merging()
  ret i32 -1

guarded1:                                         ; preds = %guarded1
  %array.3.i.ptr = getelementptr inbounds i32, i32* %array.3, i64 %i.i64
  %array.3.i = load i32, i32* %array.3.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc.1, %array.3.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:
  %result = phi i32 [ %loop.acc.next, %guarded1 ]
  ret i32 %result
}


define i32 @provably_taken(i32* %array, i32* %length.ptr) {
; CHECK-LABEL: @provably_taken(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 false, label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw nsw i32 [[I]], 1
; CHECK-NEXT:    br i1 true, label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:
  %length = load i32, i32* %length.ptr, !range !2
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp slt i32 %i.next, 200
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

; Non-latch exits can still be predicated
define i32 @unconditional_latch(i32* %a, i32 %length) {
; CHECK-LABEL: @unconditional_latch(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    br i1 false, label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    br label [[LOOP]]
;
loop.preheader:
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %i = phi i32 [ %i.next, %guarded ], [ 400, %loop.preheader ]
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  %i.next = add i32 %i, 1
  br label %loop
}

; Side effect in loop must run proper number of times
define i32 @unconditional_latch_with_side_effect(i32* %a, i32 %length) {
; CHECK-LABEL: @unconditional_latch_with_side_effect(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED:%.*]] ], [ 400, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH:%.*]]
; CHECK-NEXT:    br i1 [[WITHIN_BOUNDS]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    store volatile i32 0, i32* [[A:%.*]], align 4
; CHECK-NEXT:    [[I_NEXT]] = add i32 [[I]], 1
; CHECK-NEXT:    br label [[LOOP]]
;
loop.preheader:
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %i = phi i32 [ %i.next, %guarded ], [ 400, %loop.preheader ]
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded:                                          ; preds = %loop
  store volatile i32 0, i32* %a
  %i.next = add i32 %i, 1
  br label %loop
}

; Demonstrate that this approach works with IVs of different steps, and types
; This version uses a manually lftred exit condition to work around an issue described
; in detail on next test.
define i32 @different_ivs(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @different_ivs(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    [[N64:%.*]] = zext i32 [[N:%.*]] to i64
; CHECK-NEXT:    [[UMAX:%.*]] = call i64 @llvm.umax.i64(i64 [[N64]], i64 1)
; CHECK-NEXT:    [[TMP0:%.*]] = add nsw i64 [[UMAX]], -1
; CHECK-NEXT:    [[TMP1:%.*]] = freeze i64 [[TMP0]]
; CHECK-NEXT:    [[TMP2:%.*]] = zext i32 [[LENGTH:%.*]] to i64
; CHECK-NEXT:    [[UMIN:%.*]] = call i64 @llvm.umin.i64(i64 [[TMP1]], i64 [[TMP2]])
; CHECK-NEXT:    [[TMP3:%.*]] = zext i32 [[LENGTH]] to i64
; CHECK-NEXT:    [[TMP4:%.*]] = icmp ne i64 [[TMP3]], [[UMIN]]
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    br i1 [[TMP4]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw nsw i64 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i64 [[I_NEXT]], [[N64]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
loop.preheader:
  %j.start = sub nuw nsw i32 %length, 1
  %n64 = zext i32 %n to i64
  br label %loop

loop:
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i64 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %j = phi i32 [ %j.next, %guarded ], [ %j.start, %loop.preheader ]
  %within.bounds = icmp ne i32 %j, -1
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:
  call void @prevent_merging()
  ret i32 -1

guarded:
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i64 %i, 1
  %j.next = sub nuw i32 %j, 1
  %continue = icmp ult i64 %i.next, %n64
  br i1 %continue, label %loop, label %exit

exit:
  %result = phi i32 [ %loop.acc.next, %guarded ]
  ret i32 %result
}

; TODO: We're failing to compute an exit count for the bounds check.
; From some quick analysis, it looks like we don't handle -1 step
; in howManyLessThans.  Should be a simple fix.
define i32 @different_ivs2(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @different_ivs2(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[POS_LENGTH:%.*]] = icmp sgt i32 [[LENGTH:%.*]], 0
; CHECK-NEXT:    br i1 [[POS_LENGTH]], label [[LOOP_PREHEADER:%.*]], label [[EXIT:%.*]]
; CHECK:       loop.preheader:
; CHECK-NEXT:    [[J_START:%.*]] = sub nuw nsw i32 [[LENGTH]], 1
; CHECK-NEXT:    [[N64:%.*]] = zext i32 [[N:%.*]] to i64
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED:%.*]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[GUARDED]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    [[J:%.*]] = phi i32 [ [[J_NEXT:%.*]], [[GUARDED]] ], [ [[J_START]], [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[J]], [[LENGTH]]
; CHECK-NEXT:    br i1 [[WITHIN_BOUNDS]], label [[GUARDED]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded:
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw nsw i64 [[I]], 1
; CHECK-NEXT:    [[J_NEXT]] = sub nuw i32 [[J]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i64 [[I_NEXT]], [[N64]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT_LOOPEXIT:%.*]]
; CHECK:       exit.loopexit:
; CHECK-NEXT:    [[LOOP_ACC_NEXT_LCSSA:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED]] ]
; CHECK-NEXT:    br label [[EXIT]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[LOOP_ACC_NEXT_LCSSA]], [[EXIT_LOOPEXIT]] ]
; CHECK-NEXT:    ret i32 [[RESULT]]
;
entry:
  %pos_length = icmp sgt i32 %length, 0
  br i1 %pos_length, label %loop.preheader, label %exit

loop.preheader:
  %j.start = sub nuw nsw i32 %length, 1
  %n64 = zext i32 %n to i64
  br label %loop

loop:
  %loop.acc = phi i32 [ %loop.acc.next, %guarded ], [ 0, %loop.preheader ]
  %i = phi i64 [ %i.next, %guarded ], [ 0, %loop.preheader ]
  %j = phi i32 [ %j.next, %guarded ], [ %j.start, %loop.preheader ]
  %within.bounds = icmp ult i32 %j, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:
  call void @prevent_merging()
  ret i32 -1

guarded:
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i64 %i, 1
  %j.next = sub nuw i32 %j, 1
  %continue = icmp ult i64 %i.next, %n64
  br i1 %continue, label %loop, label %exit

exit:
  %result = phi i32 [ %loop.acc.next, %guarded ], [0, %entry]
  ret i32 %result
}

; If we have a dominating exit (exit1) which can't be itself rewritten, we
; can't rewrite a later exit (exit2).  Doing so would cause the loop to exit
; from the exit2 when it should have exited from exit1.
define i32 @neg_dominating_exit(i32* %array, i32 %length, i32 %length2, i32 %n) {
; CHECK-LABEL: @neg_dominating_exit(
; CHECK-NEXT:  loop.preheader:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[LOOP_ACC:%.*]] = phi i32 [ [[LOOP_ACC_NEXT:%.*]], [[GUARDED2:%.*]] ], [ 0, [[LOOP_PREHEADER:%.*]] ]
; CHECK-NEXT:    [[I:%.*]] = phi i32 [ [[I_NEXT:%.*]], [[GUARDED2]] ], [ 0, [[LOOP_PREHEADER]] ]
; CHECK-NEXT:    [[WITHIN_BOUNDS:%.*]] = icmp ult i32 [[I]], [[LENGTH:%.*]]
; CHECK-NEXT:    br i1 [[WITHIN_BOUNDS]], label [[GUARDED:%.*]], label [[DEOPT:%.*]], !prof [[PROF0]]
; CHECK:       deopt:
; CHECK-NEXT:    [[RESULT:%.*]] = phi i32 [ [[LOOP_ACC]], [[LOOP]] ]
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 [[RESULT]]
; CHECK:       guarded:
; CHECK-NEXT:    [[WITHIN_BOUNDS2:%.*]] = icmp ult i32 [[I]], [[LENGTH2:%.*]]
; CHECK-NEXT:    br i1 [[WITHIN_BOUNDS2]], label [[GUARDED2]], label [[DEOPT2:%.*]], !prof [[PROF0]]
; CHECK:       deopt2:
; CHECK-NEXT:    call void @prevent_merging()
; CHECK-NEXT:    ret i32 -1
; CHECK:       guarded2:
; CHECK-NEXT:    [[I_I64:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT:    [[ARRAY_I_PTR:%.*]] = getelementptr inbounds i32, i32* [[ARRAY:%.*]], i64 [[I_I64]]
; CHECK-NEXT:    [[ARRAY_I:%.*]] = load i32, i32* [[ARRAY_I_PTR]], align 4
; CHECK-NEXT:    [[LOOP_ACC_NEXT]] = add i32 [[LOOP_ACC]], [[ARRAY_I]]
; CHECK-NEXT:    [[I_NEXT]] = add nuw i32 [[I]], 1
; CHECK-NEXT:    [[CONTINUE:%.*]] = icmp ult i32 [[I_NEXT]], [[N:%.*]]
; CHECK-NEXT:    br i1 [[CONTINUE]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK:       exit:
; CHECK-NEXT:    [[RESULT2:%.*]] = phi i32 [ [[LOOP_ACC_NEXT]], [[GUARDED2]] ]
; CHECK-NEXT:    ret i32 [[RESULT2]]
;
loop.preheader:                                   ; preds = %entry
  br label %loop

loop:                                             ; preds = %guarded, %loop.preheader
  %loop.acc = phi i32 [ %loop.acc.next, %guarded2 ], [ 0, %loop.preheader ]
  %i = phi i32 [ %i.next, %guarded2 ], [ 0, %loop.preheader ]
  %within.bounds = icmp ult i32 %i, %length
  br i1 %within.bounds, label %guarded, label %deopt, !prof !0

deopt:                                            ; preds = %loop
  %result = phi i32 [ %loop.acc, %loop ]
  call void @prevent_merging()
  ret i32 %result

guarded:                                          ; preds = %loop
  %within.bounds2 = icmp ult i32 %i, %length2
  br i1 %within.bounds2, label %guarded2, label %deopt2, !prof !0

deopt2:                                            ; preds = %loop
  call void @prevent_merging()
  ret i32 -1

guarded2:                                          ; preds = %loop
  %i.i64 = zext i32 %i to i64
  %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
  %array.i = load i32, i32* %array.i.ptr, align 4
  %loop.acc.next = add i32 %loop.acc, %array.i
  %i.next = add nuw i32 %i, 1
  %continue = icmp ult i32 %i.next, %n
  br i1 %continue, label %loop, label %exit

exit:                                             ; preds = %guarded, %entry
  %result2 = phi i32 [ %loop.acc.next, %guarded2 ]
  ret i32 %result2
}


declare i32 @llvm.experimental.deoptimize.i32(...)

!0 = !{!"branch_weights", i32 1048576, i32 1}
!1 = !{i32 1, i32 -2147483648}
!2 = !{i32 0, i32 50}