| ; RUN: opt -basicaa -loop-accesses -analyze < %s | 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 |
| } |