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
|
; RUN: llc -mcpu=v2 -march=bpf < %s | FileCheck %s
; RUN: llc -mcpu=v4 -march=bpf < %s | FileCheck %s
; Zero extension instructions should be eliminated at instruction
; selection phase for all test cases below.
; In BPF zero extension is implemented as &= or a pair of <<=/>>=
; instructions, hence simply check that &= and >>= do not exist in
; generated code (<<= remains because %c is used by both call and
; lshr in a few test cases).
; CHECK-NOT: &=
; CHECK-NOT: >>=
define void @shl_lshr_same_bb(ptr %p) {
entry:
%a = load i8, ptr %p, align 1
%b = zext i8 %a to i64
%c = shl i64 %b, 56
%d = lshr i64 %c, 56
%e = icmp eq i64 %d, 0
; hasOneUse() is a common requirement for many CombineDAG
; transofmations, make sure that it does not matter in this case.
call void @sink1(i8 %a, i64 %b, i64 %c, i64 %d, i1 %e)
ret void
}
define void @shl_lshr_diff_bb(ptr %p) {
entry:
%a = load i16, ptr %p, align 2
%b = zext i16 %a to i64
%c = shl i64 %b, 48
%d = lshr i64 %c, 48
br label %next
; Jump to the new basic block creates a COPY instruction for %d, which
; might be materialized as noop or as AND_ri (zero extension) at the
; start of the basic block. The decision depends on TLI.isZExtFree()
; results, see RegsForValue::getCopyToRegs(). Check below verifies
; that COPY is materialized as noop.
next:
%e = icmp eq i64 %d, 0
call void @sink2(i16 %a, i64 %b, i64 %c, i64 %d, i1 %e)
ret void
}
define void @load_zext_same_bb(ptr %p) {
entry:
%a = load i8, ptr %p, align 1
; zext is implicit in this context
%b = icmp eq i8 %a, 0
call void @sink3(i8 %a, i1 %b)
ret void
}
define void @load_zext_diff_bb(ptr %p) {
entry:
%a = load i8, ptr %p, align 1
br label %next
next:
%b = icmp eq i8 %a, 0
call void @sink3(i8 %a, i1 %b)
ret void
}
define void @load_zext_diff_bb_2(ptr %p) {
entry:
%a = load i32, ptr %p, align 4
br label %next
next:
%b = icmp eq i32 %a, 0
call void @sink4(i32 %a, i1 %b)
ret void
}
declare void @sink1(i8, i64, i64, i64, i1);
declare void @sink2(i16, i64, i64, i64, i1);
declare void @sink3(i8, i1);
declare void @sink4(i32, i1);
|
