1 ; RUN: opt -loop-accesses -analyze < %s | FileCheck %s 2 3 ; Check that loop-indepedent forward dependences are discovered properly. 4 ; 5 ; FIXME: This does not actually always work which is pretty confusing. Right 6 ; now there is hack in LAA that tries to figure out loop-indepedent forward 7 ; dependeces *outside* of the MemoryDepChecker logic (i.e. proper dependence 8 ; analysis). 9 ; 10 ; Therefore if there is only loop-independent dependences for an array 11 ; (i.e. the same index is used), we don't discover the forward dependence. 12 ; So, at ***, we add another non-I-based access of A to trigger 13 ; MemoryDepChecker analysis for accesses of A. 14 ; 15 ; for (unsigned i = 0; i < 100; i++) { 16 ; A[i + 1] = B[i] + 1; // *** 17 ; A[i] = B[i] + 2; 18 ; C[i] = A[i] * 2; 19 ; } 20 21 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" 22 23 define void @f(i32* noalias %A, i32* noalias %B, i32* noalias %C, i64 %N) { 24 25 ; CHECK: Dependences: 26 ; CHECK-NEXT: Forward: 27 ; CHECK-NEXT: store i32 %b_p1, i32* %Aidx, align 4 -> 28 ; CHECK-NEXT: %a = load i32, i32* %Aidx, align 4 29 ; CHECK: ForwardButPreventsForwarding: 30 ; CHECK-NEXT: store i32 %b_p2, i32* %Aidx_next, align 4 -> 31 ; CHECK-NEXT: %a = load i32, i32* %Aidx, align 4 32 ; CHECK: Forward: 33 ; CHECK-NEXT: store i32 %b_p2, i32* %Aidx_next, align 4 -> 34 ; CHECK-NEXT: store i32 %b_p1, i32* %Aidx, align 4 35 36 entry: 37 br label %for.body 38 39 for.body: ; preds = %for.body, %entry 40 %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ] 41 %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 42 43 %Bidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv 44 %Cidx = getelementptr inbounds i32, i32* %C, i64 %indvars.iv 45 %Aidx_next = getelementptr inbounds i32, i32* %A, i64 %indvars.iv.next 46 %Aidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv 47 48 %b = load i32, i32* %Bidx, align 4 49 %b_p2 = add i32 %b, 1 50 store i32 %b_p2, i32* %Aidx_next, align 4 51 52 %b_p1 = add i32 %b, 2 53 store i32 %b_p1, i32* %Aidx, align 4 54 55 %a = load i32, i32* %Aidx, align 4 56 %c = mul i32 %a, 2 57 store i32 %c, i32* %Cidx, align 4 58 59 %exitcond = icmp eq i64 %indvars.iv.next, %N 60 br i1 %exitcond, label %for.end, label %for.body 61 62 for.end: ; preds = %for.body 63 ret void 64 } 65
