| Adam Nemet | e2b885c | 2015-04-23 20:09:20 +0000 | [diff] [blame] | 1 | ; RUN: opt -basicaa -loop-accesses -analyze < %s | FileCheck %s |
| 2 | |
| 3 | ; In: |
| 4 | ; |
| 5 | ; store_ptr = A; |
| 6 | ; load_ptr = &A[2]; |
| 7 | ; for (i = 0; i < n; i++) |
| 8 | ; *store_ptr++ = *load_ptr++ *10; // A[i] = A[i+2] * 10 |
| 9 | ; |
| 10 | ; make sure, we look through the PHI to conclude that store_ptr and load_ptr |
| 11 | ; both have A as their underlying object. The dependence is safe for |
| 12 | ; vectorization requiring no memchecks. |
| 13 | ; |
| 14 | ; Otherwise we would try to prove independence with a memcheck that is going |
| 15 | ; to always fail. |
| 16 | |
| 17 | target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" |
| 18 | target triple = "x86_64-apple-macosx10.10.0" |
| 19 | |
| 20 | ; CHECK: Memory dependences are safe{{$}} |
| 21 | |
| 22 | define void @f(i8* noalias %A, i64 %width) { |
| 23 | for.body.preheader: |
| 24 | %A_ahead = getelementptr inbounds i8, i8* %A, i64 2 |
| 25 | br label %for.body |
| 26 | |
| 27 | for.body: |
| 28 | %i = phi i64 [ %i.1, %for.body ], [ 0, %for.body.preheader ] |
| 29 | %load_ptr = phi i8* [ %load_ptr.1, %for.body ], [ %A_ahead, %for.body.preheader ] |
| 30 | %store_ptr = phi i8* [ %store_ptr.1, %for.body ], [ %A, %for.body.preheader ] |
| 31 | |
| 32 | %loadA = load i8, i8* %load_ptr, align 1 |
| 33 | |
| 34 | %mul = mul i8 %loadA, 10 |
| 35 | |
| 36 | store i8 %mul, i8* %store_ptr, align 1 |
| 37 | |
| 38 | %load_ptr.1 = getelementptr inbounds i8, i8* %load_ptr, i64 1 |
| 39 | %store_ptr.1 = getelementptr inbounds i8, i8* %store_ptr, i64 1 |
| 40 | %i.1 = add nuw i64 %i, 1 |
| 41 | |
| 42 | %exitcond = icmp eq i64 %i.1, %width |
| 43 | br i1 %exitcond, label %for.end, label %for.body |
| 44 | |
| 45 | for.end: |
| 46 | ret void |
| 47 | } |