nomap_writewrite.ll
2.21 KB
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
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
; RUN: opt %loadPolly -polly-delicm -analyze < %s | FileCheck %s
;
; void func(double *A) {
; for (int j = 0; j < 2; j += 1) { /* outer */
; double phi = 0.0;
; for (int i = 0; i < 4; i += 1) /* reduction */
; if (phi < 0.0)
; A[j] = undef;
; phi += 4.2;
; A[j] = phi;
; }
; }
;
; The MAY_WRITE in reduction.for.true conflict with a write of %phi to
; A[j] if %phi would be mapped to it. Being a MAY_WRITE avoids being target
; of a mapping itself.
;
; TODO: There is actually no reason why these conflict. The MAY_WRITE is an
; explicit write, defined to occur always before all implicit writes as the
; write of %phi would be. There is currently no differentiation between
; implicit and explicit writes in Polly.
;
define void @func(double* noalias nonnull %A) {
entry:
%fsomeval = fadd double 21.0, 21.0
br label %outer.preheader
outer.preheader:
br label %outer.for
outer.for:
%j = phi i32 [0, %outer.preheader], [%j.inc, %outer.inc]
%j.cmp = icmp slt i32 %j, 2
br i1 %j.cmp, label %reduction.preheader, label %outer.exit
reduction.preheader:
br label %reduction.for
reduction.for:
%i = phi i32 [0, %reduction.preheader], [%i.inc, %reduction.inc]
%phi = phi double [0.0, %reduction.preheader], [%add, %reduction.inc]
%A_idx = getelementptr inbounds double, double* %A, i32 %j
%phi.cmp = fcmp ogt double %phi, 0.0
br i1 %phi.cmp, label %reduction.for.true, label %reduction.for.unconditional
reduction.for.true:
store double undef, double* %A_idx
br label %reduction.for.unconditional
reduction.for.unconditional:
%i.cmp = icmp slt i32 %i, 4
br i1 %i.cmp, label %body, label %reduction.exit
body:
%add = fadd double %phi, 4.2
br label %reduction.inc
reduction.inc:
%i.inc = add nuw nsw i32 %i, 1
br label %reduction.for
reduction.exit:
store double %phi, double* %A_idx
br label %outer.inc
outer.inc:
%j.inc = add nuw nsw i32 %j, 1
br label %outer.for
outer.exit:
br label %return
return:
ret void
}
; CHECK: Statistics {
; CHECK: Compatible overwrites: 1
; CHECK: }
; CHECK: No modification has been made