1 ; RUN: opt -S -analyze -scalar-evolution < %s | FileCheck %s 2 3 define void @u_0(i8 %rhs) { 4 ; E.g.: %rhs = 255, %start = 99, backedge taken 156 times 5 entry: 6 %start = add i8 %rhs, 100 7 br label %loop 8 9 loop: 10 %iv = phi i8 [ %start, %entry ], [ %iv.inc, %loop ] 11 %iv.inc = add nuw i8 %iv, 1 ;; Note: this never unsigned-wraps 12 %iv.cmp = icmp ult i8 %iv, %rhs 13 br i1 %iv.cmp, label %loop, label %leave 14 15 ; CHECK-LABEL: Determining loop execution counts for: @u_0 16 ; CHECK-NEXT: Loop %loop: backedge-taken count is (-100 + (-1 * %rhs) + ((100 + %rhs) umax %rhs)) 17 ; CHECK-NEXT: Loop %loop: max backedge-taken count is -100, actual taken count either this or zero. 18 19 leave: 20 ret void 21 } 22 23 define void @u_1(i8 %start) { 24 entry: 25 ; E.g.: %start = 99, %rhs = 255, backedge taken 156 times 26 %rhs = add i8 %start, -100 27 br label %loop 28 29 loop: 30 %iv = phi i8 [ %start, %entry ], [ %iv.inc, %loop ] 31 %iv.inc = add nuw i8 %iv, 1 ;; Note: this never unsigned-wraps 32 %iv.cmp = icmp ult i8 %iv, %rhs 33 br i1 %iv.cmp, label %loop, label %leave 34 35 ; CHECK-LABEL: Determining loop execution counts for: @u_1 36 ; CHECK-NEXT: Loop %loop: backedge-taken count is ((-1 * %start) + ((-100 + %start) umax %start)) 37 ; CHECK-NEXT: Loop %loop: max backedge-taken count is -100, actual taken count either this or zero. 38 39 leave: 40 ret void 41 } 42 43 define void @s_0(i8 %rhs) { 44 entry: 45 ; E.g.: %rhs = 127, %start = -29, backedge taken 156 times 46 %start = add i8 %rhs, 100 47 br label %loop 48 49 loop: 50 %iv = phi i8 [ %start, %entry ], [ %iv.inc, %loop ] 51 %iv.inc = add nsw i8 %iv, 1 ;; Note: this never signed-wraps 52 %iv.cmp = icmp slt i8 %iv, %rhs 53 br i1 %iv.cmp, label %loop, label %leave 54 55 ; CHECK-LABEL: Determining loop execution counts for: @s_0 56 ; CHECK-NEXT: Loop %loop: backedge-taken count is (-100 + (-1 * %rhs) + ((100 + %rhs) smax %rhs)) 57 ; CHECK-NEXT: Loop %loop: max backedge-taken count is -100, actual taken count either this or zero. 58 59 leave: 60 ret void 61 } 62 63 define void @s_1(i8 %start) { 64 entry: 65 ; E.g.: start = -29, %rhs = 127, %backedge taken 156 times 66 %rhs = add i8 %start, -100 67 br label %loop 68 69 loop: 70 %iv = phi i8 [ %start, %entry ], [ %iv.inc, %loop ] 71 %iv.inc = add nsw i8 %iv, 1 72 %iv.cmp = icmp slt i8 %iv, %rhs 73 br i1 %iv.cmp, label %loop, label %leave 74 75 ; CHECK-LABEL: Determining loop execution counts for: @s_1 76 ; CHECK-NEXT: Loop %loop: backedge-taken count is ((-1 * %start) + ((-100 + %start) smax %start)) 77 ; CHECK-NEXT: Loop %loop: max backedge-taken count is -100, actual taken count either this or zero. 78 79 leave: 80 ret void 81 } 82
