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
89
90
|
; RUN: opt < %s -S -passes=loop-unroll -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=200 | FileCheck %s
; RUN: opt < %s -S -passes='require<opt-remark-emit>,loop(loop-unroll-full)' -unroll-max-iteration-count-to-analyze=1000 -unroll-threshold=10 -unroll-max-percent-threshold-boost=200 | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
@unknown_global = internal unnamed_addr global [9 x i32] [i32 0, i32 -1, i32 0, i32 -1, i32 5, i32 -1, i32 0, i32 -1, i32 0], align 16
@weak_constant = weak unnamed_addr constant [9 x i32] [i32 0, i32 -1, i32 0, i32 -1, i32 5, i32 -1, i32 0, i32 -1, i32 0], align 16
; Though @unknown_global is initialized with constant values, we can't consider
; it as a constant, so we shouldn't unroll the loop.
; CHECK-LABEL: @foo
; CHECK: %array_const_idx = getelementptr inbounds [9 x i32], ptr @unknown_global, i64 0, i64 %iv
define i32 @foo(ptr noalias nocapture readonly %src) {
entry:
br label %loop
loop: ; preds = %loop, %entry
%iv = phi i64 [ 0, %entry ], [ %inc, %loop ]
%r = phi i32 [ 0, %entry ], [ %add, %loop ]
%arrayidx = getelementptr inbounds i32, ptr %src, i64 %iv
%src_element = load i32, ptr %arrayidx, align 4
%array_const_idx = getelementptr inbounds [9 x i32], ptr @unknown_global, i64 0, i64 %iv
%const_array_element = load i32, ptr %array_const_idx, align 4
%mul = mul nsw i32 %src_element, %const_array_element
%add = add nsw i32 %mul, %r
%inc = add nuw nsw i64 %iv, 1
%exitcond86.i = icmp eq i64 %inc, 9
br i1 %exitcond86.i, label %loop.end, label %loop
loop.end: ; preds = %loop
%r.lcssa = phi i32 [ %r, %loop ]
ret i32 %r.lcssa
}
; Similarly, we can't consider 'weak' symbols as a known constant value, so we
; shouldn't unroll the loop.
; CHECK-LABEL: @foo2
; CHECK: %array_const_idx = getelementptr inbounds [9 x i32], ptr @weak_constant, i64 0, i64 %iv
define i32 @foo2(ptr noalias nocapture readonly %src) {
entry:
br label %loop
loop: ; preds = %loop, %entry
%iv = phi i64 [ 0, %entry ], [ %inc, %loop ]
%r = phi i32 [ 0, %entry ], [ %add, %loop ]
%arrayidx = getelementptr inbounds i32, ptr %src, i64 %iv
%src_element = load i32, ptr %arrayidx, align 4
%array_const_idx = getelementptr inbounds [9 x i32], ptr @weak_constant, i64 0, i64 %iv
%const_array_element = load i32, ptr %array_const_idx, align 4
%mul = mul nsw i32 %src_element, %const_array_element
%add = add nsw i32 %mul, %r
%inc = add nuw nsw i64 %iv, 1
%exitcond86.i = icmp eq i64 %inc, 9
br i1 %exitcond86.i, label %loop.end, label %loop
loop.end: ; preds = %loop
%r.lcssa = phi i32 [ %r, %loop ]
ret i32 %r.lcssa
}
; In this case the loaded value is used only to control branch.
; If we missed that, we could've thought that it's unused and unrolling would
; clean up almost entire loop. Make sure that we do not unroll such loop.
; CHECK-LABEL: @foo3
; CHECK: br i1 %exitcond, label %loop.end, label %loop.header
define i32 @foo3(ptr noalias nocapture readonly %src) {
entry:
br label %loop.header
loop.header:
%iv = phi i64 [ 0, %entry ], [ %inc, %loop.latch ]
%r1 = phi i32 [ 0, %entry ], [ %r3, %loop.latch ]
%arrayidx = getelementptr inbounds i32, ptr %src, i64 %iv
%src_element = load i32, ptr %arrayidx, align 4
%cmp = icmp eq i32 0, %src_element
br i1 %cmp, label %loop.if, label %loop.latch
loop.if:
%r2 = add i32 %r1, 1
br label %loop.latch
loop.latch:
%r3 = phi i32 [%r1, %loop.header], [%r2, %loop.if]
%inc = add nuw nsw i64 %iv, 1
%exitcond = icmp eq i64 %inc, 9
br i1 %exitcond, label %loop.end, label %loop.header
loop.end:
%r.lcssa = phi i32 [ %r3, %loop.latch ]
ret i32 %r.lcssa
}
|
