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[DA] Add test where access size differs from stride size (NFC) #147715

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Merged
merged 1 commit into from
Jul 10, 2025
+47 −1
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[DA] Add test where access size differs from stride size (NFC) #147715

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48 changes: 47 additions & 1 deletion llvm/test/Analysis/DependenceAnalysis/DifferentOffsets.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -149,11 +149,11 @@ define void @multidim_accesses(ptr %A) {
; CHECK-NEXT: Src: store i32 1, ptr %idx0, align 4 --> Dst: store i32 1, ptr %idx0, align 4
; CHECK-NEXT: da analyze - none!
; CHECK-NEXT: Src: store i32 1, ptr %idx0, align 4 --> Dst: store i32 1, ptr %idx1, align 4
; FIXME: the dependence distance is not constant. Distance vector should be [* * *|<]!
; CHECK-NEXT: da analyze - consistent output [0 0 0|<]!
; CHECK-NEXT: Src: store i32 1, ptr %idx1, align 4 --> Dst: store i32 1, ptr %idx1, align 4
; CHECK-NEXT: da analyze - none!
;
; FIXME: the dependence distance is not constant. Distance vector should be [* * *|<]!
; for (i = 0; i < 256; i++)
; for (j = 0; j < 256; j++)
; for (k = 0; k < 256; k++) {
Expand Down Expand Up @@ -199,3 +199,49 @@ for.i.inc:
end:
ret void
}

; for (int i = 0; i < 256; i++)
; for (int j = 0; j < 256; j++)
; for (int k = 0; k < 256; k++) {
; int *idx = (int *)((int *)(A) + 256*256*i + 256*j + k);
; *((long long *)idx) = 1;
; }
;
; FIXME: There are loop-carried dependencies across iterations in the store.
define void @multidim_accesses2(ptr %A) {
; CHECK-LABEL: 'multidim_accesses2'
; CHECK-NEXT: Src: store i64 1, ptr %idx, align 4 --> Dst: store i64 1, ptr %idx, align 4
; CHECK-NEXT: da analyze - none!
;
entry:
br label %for.i

for.i:
%i = phi i64 [ 0, %entry ], [ %i.inc, %for.i.inc ]
br label %for.j

for.j:
%j = phi i64 [ 0, %for.i ], [ %j.inc, %for.j.inc ]
br label %for.k

for.k:
%k = phi i64 [ 0, %for.j ], [ %k.inc, %for.k ]
%idx = getelementptr inbounds [256 x [256 x [256 x i32]]], ptr %A, i64 0, i64 %i, i64 %j, i64 %k
store i64 1, ptr %idx
%k.inc = add nsw i64 %k, 1
%k.exitcond = icmp eq i64 %k.inc, 256
br i1 %k.exitcond, label %for.j.inc, label %for.k

for.j.inc:
%j.inc = add nsw i64 %j, 1
%j.exitcond = icmp eq i64 %j.inc, 256
br i1 %j.exitcond, label %for.i.inc, label %for.j

for.i.inc:
%i.inc = add nsw i64 %i, 1
%i.exitcond = icmp eq i64 %i.inc, 256
br i1 %i.exitcond, label %end, label %for.i

end:
ret void
}