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gerrit-public.fairphone.software / toolchain / llvm-project / b6d40cceeed08876e6d633099de7c5c15f66c453 / . / llvm / test / Transforms / JumpThreading / guards.ll
blob: c5f72b113efcec83747bcb5fb02e1fef4a17451e [file] [log] [blame]
Sanjoy Das8b859c22017-02-17 04:21:14 +0000[diff] [blame]1; RUN: opt < %s -jump-threading -dce -S | FileCheck %s
2
3declare void @llvm.experimental.guard(i1, ...)
4
5declare i32 @f1()
6declare i32 @f2()
7
8define i32 @branch_implies_guard(i32 %a) {
9; CHECK-LABEL: @branch_implies_guard(
10 %cond = icmp slt i32 %a, 10
11 br i1 %cond, label %T1, label %F1
12
13T1:
14; CHECK: T1.split
15; CHECK: %v1 = call i32 @f1()
16; CHECK-NEXT: %retVal
17; CHECK-NEXT: br label %Merge
18 %v1 = call i32 @f1()
19 br label %Merge
20
21F1:
22; CHECK: F1.split
23; CHECK: %v2 = call i32 @f2()
24; CHECK-NEXT: %retVal
25; CHECK-NEXT: %condGuard
26; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard
27; CHECK-NEXT: br label %Merge
28 %v2 = call i32 @f2()
29 br label %Merge
30
31Merge:
32; CHECK: Merge
33; CHECK-NOT: call void(i1, ...) @llvm.experimental.guard(
34 %retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
35 %retVal = add i32 %retPhi, 10
36 %condGuard = icmp slt i32 %a, 20
37 call void(i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
38 ret i32 %retVal
39}
40
41define i32 @not_branch_implies_guard(i32 %a) {
42; CHECK-LABEL: @not_branch_implies_guard(
43 %cond = icmp slt i32 %a, 20
44 br i1 %cond, label %T1, label %F1
45
46T1:
47; CHECK: T1.split:
48; CHECK-NEXT: %v1 = call i32 @f1()
49; CHECK-NEXT: %retVal
50; CHECK-NEXT: %condGuard
51; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard
52; CHECK-NEXT: br label %Merge
53 %v1 = call i32 @f1()
54 br label %Merge
55
56F1:
57; CHECK: F1.split:
58; CHECK-NEXT: %v2 = call i32 @f2()
59; CHECK-NEXT: %retVal
60; CHECK-NEXT: br label %Merge
61 %v2 = call i32 @f2()
62 br label %Merge
63
64Merge:
65; CHECK: Merge
66; CHECK-NOT: call void(i1, ...) @llvm.experimental.guard(
67 %retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
68 %retVal = add i32 %retPhi, 10
69 %condGuard = icmp sgt i32 %a, 10
70 call void(i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
71 ret i32 %retVal
72}
73
74define i32 @branch_overlaps_guard(i32 %a) {
75; CHECK-LABEL: @branch_overlaps_guard(
76 %cond = icmp slt i32 %a, 20
77 br i1 %cond, label %T1, label %F1
78
79T1:
80; CHECK: T1:
81; CHECK-NEXT: %v1 = call i32 @f1()
82; CHECK-NEXT: br label %Merge
83 %v1 = call i32 @f1()
84 br label %Merge
85
86F1:
87; CHECK: F1:
88; CHECK-NEXT: %v2 = call i32 @f2()
89; CHECK-NEXT: br label %Merge
90 %v2 = call i32 @f2()
91 br label %Merge
92
93Merge:
94; CHECK: Merge
95; CHECK: %condGuard = icmp slt i32 %a, 10
96; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
97 %retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
98 %retVal = add i32 %retPhi, 10
99 %condGuard = icmp slt i32 %a, 10
100 call void(i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
101 ret i32 %retVal
102}
103
104define i32 @branch_doesnt_overlap_guard(i32 %a) {
105; CHECK-LABEL: @branch_doesnt_overlap_guard(
106 %cond = icmp slt i32 %a, 10
107 br i1 %cond, label %T1, label %F1
108
109T1:
110; CHECK: T1:
111; CHECK-NEXT: %v1 = call i32 @f1()
112; CHECK-NEXT: br label %Merge
113 %v1 = call i32 @f1()
114 br label %Merge
115
116F1:
117; CHECK: F1:
118; CHECK-NEXT: %v2 = call i32 @f2()
119; CHECK-NEXT: br label %Merge
120 %v2 = call i32 @f2()
121 br label %Merge
122
123Merge:
124; CHECK: Merge
125; CHECK: %condGuard = icmp sgt i32 %a, 20
126; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
127 %retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
128 %retVal = add i32 %retPhi, 10
129 %condGuard = icmp sgt i32 %a, 20
130 call void(i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
131 ret i32 %retVal
132}
133
134define i32 @not_a_diamond1(i32 %a, i1 %cond1) {
135; CHECK-LABEL: @not_a_diamond1(
136 br i1 %cond1, label %Pred, label %Exit
137
138Pred:
139; CHECK: Pred:
140; CHECK-NEXT: switch i32 %a, label %Exit
141 switch i32 %a, label %Exit [
142 i32 10, label %Merge
143 i32 20, label %Merge
144 ]
145
146Merge:
147; CHECK: Merge:
148; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
149; CHECK-NEXT: br label %Exit
150 call void(i1, ...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
151 br label %Exit
152
153Exit:
154; CHECK: Exit:
155; CHECK-NEXT: ret i32 %a
156 ret i32 %a
157}
158
159define void @not_a_diamond2(i32 %a, i1 %cond1) {
160; CHECK-LABEL: @not_a_diamond2(
161 br label %Parent
162
163Merge:
164 call void(i1, ...) @llvm.experimental.guard(i1 %cond1)[ "deopt"() ]
165 ret void
166
167Pred:
168; CHECK-NEXT: Pred:
169; CHECK-NEXT: switch i32 %a, label %Exit
170 switch i32 %a, label %Exit [
171 i32 10, label %Merge
172 i32 20, label %Merge
173 ]
174
175Parent:
176 br label %Pred
177
178Exit:
179; CHECK: Merge:
180; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
181; CHECK-NEXT: ret void
182 ret void
183}
Anna Thomas7bca5912017-05-18 13:12:18 +0000[diff] [blame]184
185declare void @never_called()
186
187; Assume the guard is always taken and we deoptimize, so we never reach the
188; branch below that guard. We should *never* change the behaviour of a guard from
189; `must deoptimize` to `may deoptimize`, since this affects the program
190; semantics.
191define void @dont_fold_guard(i8* %addr, i32 %i, i32 %length) {
192; CHECK-LABEL: dont_fold_guard
193; CHECK: experimental.guard(i1 %wide.chk)
194
195entry:
196 br label %BBPred
197
198BBPred:
199 %cond = icmp eq i8* %addr, null
200 br i1 %cond, label %zero, label %not_zero
201
202zero:
203 unreachable
204
205not_zero:
206 %c1 = icmp ult i32 %i, %length
207 %c2 = icmp eq i32 %i, 0
208 %wide.chk = and i1 %c1, %c2
209 call void(i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
210 br i1 %c2, label %unreachedBB2, label %unreachedBB1
211
212unreachedBB2:
213 call void @never_called()
214 ret void
215
216unreachedBB1:
217 ret void
218}
219
220
221; same as dont_fold_guard1 but condition %cmp is not an instruction.
222; We cannot fold the guard under any circumstance.
223; FIXME: We can merge unreachableBB2 into not_zero.
224define void @dont_fold_guard2(i8* %addr, i1 %cmp, i32 %i, i32 %length) {
225; CHECK-LABEL: dont_fold_guard2
226; CHECK: guard(i1 %cmp)
227
228entry:
229 br label %BBPred
230
231BBPred:
232 %cond = icmp eq i8* %addr, null
233 br i1 %cond, label %zero, label %not_zero
234
235zero:
236 unreachable
237
238not_zero:
239 call void(i1, ...) @llvm.experimental.guard(i1 %cmp) [ "deopt"() ]
240 br i1 %cmp, label %unreachedBB2, label %unreachedBB1
241
242unreachedBB2:
243 call void @never_called()
244 ret void
245
246unreachedBB1:
247 ret void
248}
249
250; Same as dont_fold_guard1 but use switch instead of branch.
251; triggers source code `ProcessThreadableEdges`.
252declare void @f(i1)
253define void @dont_fold_guard3(i1 %cmp1, i32 %i) nounwind {
254; CHECK-LABEL: dont_fold_guard3
255; CHECK-LABEL: L2:
256; CHECK-NEXT: %cmp = icmp eq i32 %i, 0
257; CHECK-NEXT: guard(i1 %cmp)
258; CHECK-NEXT: @f(i1 %cmp)
259; CHECK-NEXT: ret void
260entry:
261 br i1 %cmp1, label %L0, label %L3
262L0:
263 %cmp = icmp eq i32 %i, 0
264 call void(i1, ...) @llvm.experimental.guard(i1 %cmp) [ "deopt"() ]
265 switch i1 %cmp, label %L3 [
266 i1 false, label %L1
267 i1 true, label %L2
268 ]
269
270L1:
271 ret void
272L2:
273 call void @f(i1 %cmp)
274 ret void
275L3:
276 ret void
277}