1; REQUIRES: asserts 2; RUN: opt -passes='print<access-info>' -debug-only=loop-accesses -disable-output < %s 2>&1 | FileCheck %s 3 4; void negative_step(int *A) { 5; for (int i = 1022; i >= 0; i--) 6; A[i+1] = A[i] + 1; 7; } 8 9; CHECK-LABEL: 'negative_step' 10; CHECK: LAA: Found an analyzable loop: loop 11; CHECK: LAA: Checking memory dependencies 12; CHECK-NEXT: LAA: Src Scev: {(4092 + %A),+,-4}<nw><%loop>Sink Scev: {(4088 + %A)<nuw>,+,-4}<nw><%loop> 13; CHECK-NEXT: LAA: Distance for store i32 %add, ptr %gep.A.plus.1, align 4 to %l = load i32, ptr %gep.A, align 4: -4 14; CHECK-NEXT: LAA: Src induction step: -1 Sink induction step: -1 15; CHECK-NEXT: LAA: Dependence is negative 16 17define void @negative_step(ptr nocapture %A) { 18entry: 19 %A.plus.1 = getelementptr i32, ptr %A, i64 1 20 br label %loop 21 22loop: 23 %iv = phi i64 [ 1022, %entry ], [ %iv.next, %loop ] 24 %gep.A = getelementptr inbounds i32, ptr %A, i64 %iv 25 %l = load i32, ptr %gep.A, align 4 26 %add = add nsw i32 %l, 1 27 %gep.A.plus.1 = getelementptr i32, ptr %A.plus.1, i64 %iv 28 store i32 %add, ptr %gep.A.plus.1, align 4 29 %iv.next = add nsw i64 %iv, -1 30 %cmp.not = icmp eq i64 %iv, 0 31 br i1 %cmp.not, label %exit, label %loop 32 33exit: 34 ret void 35} 36 37; void positive_step(int *A) { 38; for (int i = 1; i < 1024; i++) 39; A[i-1] = A[i] + 1; 40; } 41 42; CHECK-LABEL: 'positive_step' 43; CHECK: LAA: Found an analyzable loop: loop 44; CHECK: LAA: Checking memory dependencies 45; CHECK-NEXT: LAA: Src Scev: {(4 + %A)<nuw>,+,4}<nuw><%loop>Sink Scev: {%A,+,4}<nw><%loop> 46; CHECK-NEXT: LAA: Distance for %l = load i32, ptr %gep.A, align 4 to store i32 %add, ptr %gep.A.minus.1, align 4: -4 47; CHECK-NEXT: LAA: Src induction step: 1 Sink induction step: 1 48; CHECK-NEXT: LAA: Dependence is negative 49 50define void @positive_step(ptr nocapture %A) { 51entry: 52 %A.minus.1 = getelementptr i32, ptr %A, i64 -1 53 br label %loop 54 55loop: 56 %iv = phi i64 [ 1, %entry ], [ %iv.next, %loop ] 57 %gep.A = getelementptr inbounds i32, ptr %A, i64 %iv 58 %l = load i32, ptr %gep.A, align 4 59 %add = add nsw i32 %l, 1 60 %gep.A.minus.1 = getelementptr i32, ptr %A.minus.1, i64 %iv 61 store i32 %add, ptr %gep.A.minus.1, align 4 62 %iv.next = add nsw i64 %iv, 1 63 %cmp.not = icmp eq i64 %iv, 1024 64 br i1 %cmp.not, label %exit, label %loop 65 66exit: 67 ret void 68} 69 70