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1; RUN: opt -analyze --loop-accesses %s | FileCheck %s
2
3; This test verifies run-time boundary check of memory accesses.
4; The original loop:
5;   void fastCopy(const char* src, char* op) {
6;     int len = 32;
7;     while (len > 0) {
8;       *(reinterpret_cast<long long*>(op)) = *(reinterpret_cast<const long long*>(src));
9;       src += 8;
10;       op += 8;
11;       len -= 8;
12;     }
13;   }
14; Boundaries calculations before this patch:
15; (Low: %src High: (24 + %src))
16; and the actual distance between two pointers was 31,  (%op - %src = 31)
17; IsConflict = (24 > 31) = false -> execution is directed to the vectorized loop.
18; The loop was vectorized to 4, 32 byte memory access ( <4 x i64> ),
19; store a value at *%op touched memory under *%src.
20
21;CHECK: Printing analysis 'Loop Access Analysis' for function 'fastCopy'
22;CHECK: (Low: %op High: (32 + %op))
23;CHECK: (Low: %src High: (32 + %src))
24
25define void @fastCopy(i8* nocapture readonly %src, i8* nocapture %op) {
26entry:
27  br label %while.body.preheader
28
29while.body.preheader:                             ; preds = %entry
30  br label %while.body
31
32while.body:                                       ; preds = %while.body.preheader, %while.body
33  %len.addr.07 = phi i32 [ %sub, %while.body ], [ 32, %while.body.preheader ]
34  %op.addr.06 = phi i8* [ %add.ptr1, %while.body ], [ %op, %while.body.preheader ]
35  %src.addr.05 = phi i8* [ %add.ptr, %while.body ], [ %src, %while.body.preheader ]
36  %0 = bitcast i8* %src.addr.05 to i64*
37  %1 = load i64, i64* %0, align 8
38  %2 = bitcast i8* %op.addr.06 to i64*
39  store i64 %1, i64* %2, align 8
40  %add.ptr = getelementptr inbounds i8, i8* %src.addr.05, i64 8
41  %add.ptr1 = getelementptr inbounds i8, i8* %op.addr.06, i64 8
42  %sub = add nsw i32 %len.addr.07, -8
43  %cmp = icmp sgt i32 %len.addr.07, 8
44  br i1 %cmp, label %while.body, label %while.end.loopexit
45
46while.end.loopexit:                               ; preds = %while.body
47  br label %while.end
48
49while.end:                                        ; preds = %while.end.loopexit, %entry
50  ret void
51}
52