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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
| ; XFAIL: *
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -mtriple=amdgcn-amd-amdhsa -S -structurizecfg %s | FileCheck %s
; StructurizeCFG::orderNodes used an arbitrary and nonsensical sorting
; function which broke the basic backedge identification algorithm. It
; would use RPO order, but then do a weird partial sort by the loop
; depth assuming blocks are sorted by loop. However a block can appear
; in between blocks of a loop that is not part of a loop, breaking the
; assumption of the sort.
;
; The collectInfos must be done in RPO order. The actual
; structurization order I think is less important, but unless the loop
; headers are identified in RPO order, it finds the wrong set of back
; edges.
define amdgpu_kernel void @loop_backedge_misidentified(i32 addrspace(1)* %arg0) #0 {
; CHECK-LABEL: @loop_backedge_misidentified(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP:%.*]] = load volatile <2 x i32>, <2 x i32> addrspace(1)* undef, align 16
; CHECK-NEXT: [[LOAD1:%.*]] = load volatile <2 x float>, <2 x float> addrspace(1)* undef
; CHECK-NEXT: [[TID:%.*]] = call i32 @llvm.amdgcn.workitem.id.x()
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i32, i32 addrspace(1)* [[ARG0:%.*]], i32 [[TID]]
; CHECK-NEXT: [[I_INITIAL:%.*]] = load volatile i32, i32 addrspace(1)* [[GEP]], align 4
; CHECK-NEXT: br label [[LOOP_HEADER:%.*]]
; CHECK: LOOP.HEADER:
; CHECK-NEXT: [[I:%.*]] = phi i32 [ [[I_INITIAL]], [[ENTRY:%.*]] ], [ [[TMP10:%.*]], [[FLOW4:%.*]] ]
; CHECK-NEXT: call void asm sideeffect "s_nop 0x100b
; CHECK-NEXT: [[TMP12:%.*]] = zext i32 [[I]] to i64
; CHECK-NEXT: [[TMP13:%.*]] = getelementptr inbounds <4 x i32>, <4 x i32> addrspace(1)* null, i64 [[TMP12]]
; CHECK-NEXT: [[TMP14:%.*]] = load <4 x i32>, <4 x i32> addrspace(1)* [[TMP13]], align 16
; CHECK-NEXT: [[TMP15:%.*]] = extractelement <4 x i32> [[TMP14]], i64 0
; CHECK-NEXT: [[TMP16:%.*]] = and i32 [[TMP15]], 65535
; CHECK-NEXT: [[TMP17:%.*]] = icmp eq i32 [[TMP16]], 1
; CHECK-NEXT: [[TMP0:%.*]] = xor i1 [[TMP17]], true
; CHECK-NEXT: br i1 [[TMP0]], label [[BB62:%.*]], label [[FLOW:%.*]]
; CHECK: Flow2:
; CHECK-NEXT: br label [[FLOW]]
; CHECK: bb18:
; CHECK-NEXT: [[TMP19:%.*]] = extractelement <2 x i32> [[TMP]], i64 0
; CHECK-NEXT: [[TMP22:%.*]] = lshr i32 [[TMP19]], 16
; CHECK-NEXT: [[TMP24:%.*]] = urem i32 [[TMP22]], 52
; CHECK-NEXT: [[TMP25:%.*]] = mul nuw nsw i32 [[TMP24]], 52
; CHECK-NEXT: br label [[INNER_LOOP:%.*]]
; CHECK: Flow3:
; CHECK-NEXT: [[TMP1:%.*]] = phi i32 [ [[TMP59:%.*]], [[INNER_LOOP_BREAK:%.*]] ], [ [[TMP7:%.*]], [[FLOW]] ]
; CHECK-NEXT: [[TMP2:%.*]] = phi i1 [ true, [[INNER_LOOP_BREAK]] ], [ [[TMP8:%.*]], [[FLOW]] ]
; CHECK-NEXT: br i1 [[TMP2]], label [[END_ELSE_BLOCK:%.*]], label [[FLOW4]]
; CHECK: INNER_LOOP:
; CHECK-NEXT: [[INNER_LOOP_J:%.*]] = phi i32 [ [[INNER_LOOP_J_INC:%.*]], [[INNER_LOOP]] ], [ [[TMP25]], [[BB18:%.*]] ]
; CHECK-NEXT: call void asm sideeffect "
; CHECK-NEXT: [[INNER_LOOP_J_INC]] = add nsw i32 [[INNER_LOOP_J]], 1
; CHECK-NEXT: [[INNER_LOOP_CMP:%.*]] = icmp eq i32 [[INNER_LOOP_J]], 0
; CHECK-NEXT: br i1 [[INNER_LOOP_CMP]], label [[INNER_LOOP_BREAK]], label [[INNER_LOOP]]
; CHECK: INNER_LOOP_BREAK:
; CHECK-NEXT: [[TMP59]] = extractelement <4 x i32> [[TMP14]], i64 2
; CHECK-NEXT: call void asm sideeffect "s_nop 23 ", "~{memory}"() #0
; CHECK-NEXT: br label [[FLOW3:%.*]]
; CHECK: bb62:
; CHECK-NEXT: [[LOAD13:%.*]] = icmp ult i32 [[TMP16]], 271
; CHECK-NEXT: [[TMP3:%.*]] = xor i1 [[LOAD13]], true
; CHECK-NEXT: br i1 [[TMP3]], label [[INCREMENT_I:%.*]], label [[FLOW1:%.*]]
; CHECK: Flow1:
; CHECK-NEXT: [[TMP4:%.*]] = phi i32 [ [[INC_I:%.*]], [[INCREMENT_I]] ], [ undef, [[BB62]] ]
; CHECK-NEXT: [[TMP5:%.*]] = phi i1 [ true, [[INCREMENT_I]] ], [ false, [[BB62]] ]
; CHECK-NEXT: [[TMP6:%.*]] = phi i1 [ false, [[INCREMENT_I]] ], [ true, [[BB62]] ]
; CHECK-NEXT: br i1 [[TMP6]], label [[BB64:%.*]], label [[FLOW2:%.*]]
; CHECK: bb64:
; CHECK-NEXT: call void asm sideeffect "s_nop 42", "~{memory}"() #0
; CHECK-NEXT: br label [[FLOW2]]
; CHECK: Flow:
; CHECK-NEXT: [[TMP7]] = phi i32 [ [[TMP4]], [[FLOW2]] ], [ undef, [[LOOP_HEADER]] ]
; CHECK-NEXT: [[TMP8]] = phi i1 [ [[TMP5]], [[FLOW2]] ], [ false, [[LOOP_HEADER]] ]
; CHECK-NEXT: [[TMP9:%.*]] = phi i1 [ false, [[FLOW2]] ], [ true, [[LOOP_HEADER]] ]
; CHECK-NEXT: br i1 [[TMP9]], label [[BB18]], label [[FLOW3]]
; CHECK: INCREMENT_I:
; CHECK-NEXT: [[INC_I]] = add i32 [[I]], 1
; CHECK-NEXT: call void asm sideeffect "s_nop 0x1336
; CHECK-NEXT: br label [[FLOW1]]
; CHECK: END_ELSE_BLOCK:
; CHECK-NEXT: [[I_FINAL:%.*]] = phi i32 [ [[TMP1]], [[FLOW3]] ]
; CHECK-NEXT: call void asm sideeffect "s_nop 0x1337
; CHECK-NEXT: [[CMP_END_ELSE_BLOCK:%.*]] = icmp eq i32 [[I_FINAL]], -1
; CHECK-NEXT: br label [[FLOW4]]
; CHECK: Flow4:
; CHECK-NEXT: [[TMP10]] = phi i32 [ [[I_FINAL]], [[END_ELSE_BLOCK]] ], [ undef, [[FLOW3]] ]
; CHECK-NEXT: [[TMP11:%.*]] = phi i1 [ [[CMP_END_ELSE_BLOCK]], [[END_ELSE_BLOCK]] ], [ true, [[FLOW3]] ]
; CHECK-NEXT: br i1 [[TMP11]], label [[RETURN:%.*]], label [[LOOP_HEADER]]
; CHECK: RETURN:
; CHECK-NEXT: call void asm sideeffect "s_nop 0x99
; CHECK-NEXT: store volatile <2 x float> [[LOAD1]], <2 x float> addrspace(1)* undef, align 8
; CHECK-NEXT: ret void
;
entry:
%tmp = load volatile <2 x i32>, <2 x i32> addrspace(1)* undef, align 16
%load1 = load volatile <2 x float>, <2 x float> addrspace(1)* undef
%tid = call i32 @llvm.amdgcn.workitem.id.x()
%gep = getelementptr inbounds i32, i32 addrspace(1)* %arg0, i32 %tid
%i.initial = load volatile i32, i32 addrspace(1)* %gep, align 4
br label %LOOP.HEADER
LOOP.HEADER:
%i = phi i32 [ %i.final, %END_ELSE_BLOCK ], [ %i.initial, %entry ]
call void asm sideeffect "s_nop 0x100b ; loop $0 ", "r,~{memory}"(i32 %i) #0
%tmp12 = zext i32 %i to i64
%tmp13 = getelementptr inbounds <4 x i32>, <4 x i32> addrspace(1)* null, i64 %tmp12
%tmp14 = load <4 x i32>, <4 x i32> addrspace(1)* %tmp13, align 16
%tmp15 = extractelement <4 x i32> %tmp14, i64 0
%tmp16 = and i32 %tmp15, 65535
%tmp17 = icmp eq i32 %tmp16, 1
br i1 %tmp17, label %bb18, label %bb62
bb18:
%tmp19 = extractelement <2 x i32> %tmp, i64 0
%tmp22 = lshr i32 %tmp19, 16
%tmp24 = urem i32 %tmp22, 52
%tmp25 = mul nuw nsw i32 %tmp24, 52
br label %INNER_LOOP
INNER_LOOP:
%inner.loop.j = phi i32 [ %tmp25, %bb18 ], [ %inner.loop.j.inc, %INNER_LOOP ]
call void asm sideeffect "; inner loop body", ""() #0
%inner.loop.j.inc = add nsw i32 %inner.loop.j, 1
%inner.loop.cmp = icmp eq i32 %inner.loop.j, 0
br i1 %inner.loop.cmp, label %INNER_LOOP_BREAK, label %INNER_LOOP
INNER_LOOP_BREAK:
%tmp59 = extractelement <4 x i32> %tmp14, i64 2
call void asm sideeffect "s_nop 23 ", "~{memory}"() #0
br label %END_ELSE_BLOCK
bb62:
%load13 = icmp ult i32 %tmp16, 271
br i1 %load13, label %bb64, label %INCREMENT_I
bb64:
call void asm sideeffect "s_nop 42", "~{memory}"() #0
br label %RETURN
INCREMENT_I:
%inc.i = add i32 %i, 1
call void asm sideeffect "s_nop 0x1336 ; increment $0", "v,~{memory}"(i32 %inc.i) #0
br label %END_ELSE_BLOCK
END_ELSE_BLOCK:
%i.final = phi i32 [ %tmp59, %INNER_LOOP_BREAK ], [ %inc.i, %INCREMENT_I ]
call void asm sideeffect "s_nop 0x1337 ; end else block $0", "v,~{memory}"(i32 %i.final) #0
%cmp.end.else.block = icmp eq i32 %i.final, -1
br i1 %cmp.end.else.block, label %RETURN, label %LOOP.HEADER
RETURN:
call void asm sideeffect "s_nop 0x99 ; ClosureEval return", "~{memory}"() #0
store volatile <2 x float> %load1, <2 x float> addrspace(1)* undef, align 8
ret void
}
; The same function, except break to return block goes directly to the
; return, which managed to hide the bug.
; FIXME: Merge variant from backedge-id-bug-xfail
declare i32 @llvm.amdgcn.workitem.id.x() #1
attributes #0 = { convergent nounwind }
attributes #1 = { convergent nounwind readnone }
|