1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
| ; RUN: opt -basicaa -loop-accesses -analyze < %s | FileCheck %s
; RUN: opt -passes='require<aa>,require<scalar-evolution>,require<aa>,loop(print-access-info)' -aa-pipeline='basic-aa' -disable-output < %s 2>&1 | FileCheck %s
; For this loop:
; for (int i = 0; i < n; i++)
; A[2 * i] = A[2 * i] + B[i];
;
; , SCEV is unable to prove that A[2 * i] does not overflow. However,
; analyzing the IR helps us to conclude it and in turn allow dependence
; analysis.
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
; CHECK: Memory dependences are safe{{$}}
define void @f(i16* noalias %a,
i16* noalias %b, i64 %N) {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%ind = phi i64 [ 0, %entry ], [ %inc, %for.body ]
%mul = mul nuw nsw i64 %ind, 2
%arrayidxA = getelementptr inbounds i16, i16* %a, i64 %mul
%loadA = load i16, i16* %arrayidxA, align 2
%arrayidxB = getelementptr inbounds i16, i16* %b, i64 %ind
%loadB = load i16, i16* %arrayidxB, align 2
%add = mul i16 %loadA, %loadB
store i16 %add, i16* %arrayidxA, align 2
%inc = add nuw nsw i64 %ind, 1
%exitcond = icmp eq i64 %inc, %N
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
|