1 //===- llvm/unittests/IR/DominatorTreeTest.cpp - Constants unit tests -----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include <random>
10 #include "llvm/Analysis/PostDominators.h"
11 #include "llvm/Analysis/IteratedDominanceFrontier.h"
12 #include "llvm/AsmParser/Parser.h"
13 #include "llvm/IR/Constants.h"
14 #include "llvm/IR/Dominators.h"
15 #include "llvm/IR/Instructions.h"
16 #include "llvm/IR/LLVMContext.h"
17 #include "llvm/IR/Module.h"
18 #include "llvm/Support/SourceMgr.h"
19 #include "CFGBuilder.h"
20 #include "gtest/gtest.h"
21
22 using namespace llvm;
23
24
25 /// Build the dominator tree for the function and run the Test.
runWithDomTree(Module & M,StringRef FuncName,function_ref<void (Function & F,DominatorTree * DT,PostDominatorTree * PDT)> Test)26 static void runWithDomTree(
27 Module &M, StringRef FuncName,
28 function_ref<void(Function &F, DominatorTree *DT, PostDominatorTree *PDT)>
29 Test) {
30 auto *F = M.getFunction(FuncName);
31 ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
32 // Compute the dominator tree for the function.
33 DominatorTree DT(*F);
34 PostDominatorTree PDT(*F);
35 Test(*F, &DT, &PDT);
36 }
37
makeLLVMModule(LLVMContext & Context,StringRef ModuleStr)38 static std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
39 StringRef ModuleStr) {
40 SMDiagnostic Err;
41 std::unique_ptr<Module> M = parseAssemblyString(ModuleStr, Err, Context);
42 assert(M && "Bad assembly?");
43 return M;
44 }
45
TEST(DominatorTree,PHIs)46 TEST(DominatorTree, PHIs) {
47 StringRef ModuleString = R"(
48 define void @f() {
49 bb1:
50 br label %bb1
51 bb2:
52 %a = phi i32 [0, %bb1], [1, %bb2]
53 %b = phi i32 [2, %bb1], [%a, %bb2]
54 br label %bb2
55 };
56 )";
57
58 // Parse the module.
59 LLVMContext Context;
60 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
61
62 runWithDomTree(*M, "f",
63 [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
64 auto FI = F.begin();
65 ++FI;
66 BasicBlock *BB2 = &*FI;
67 auto BI = BB2->begin();
68 Instruction *PhiA = &*BI++;
69 Instruction *PhiB = &*BI;
70
71 // Phis are thought to execute "instantly, together".
72 EXPECT_TRUE(DT->dominates(PhiA, PhiB));
73 EXPECT_TRUE(DT->dominates(PhiB, PhiA));
74 });
75 }
76
TEST(DominatorTree,Unreachable)77 TEST(DominatorTree, Unreachable) {
78 StringRef ModuleString =
79 "declare i32 @g()\n"
80 "define void @f(i32 %x) personality i32 ()* @g {\n"
81 "bb0:\n"
82 " %y1 = add i32 %x, 1\n"
83 " %y2 = add i32 %x, 1\n"
84 " %y3 = invoke i32 @g() to label %bb1 unwind label %bb2\n"
85 "bb1:\n"
86 " %y4 = add i32 %x, 1\n"
87 " br label %bb4\n"
88 "bb2:\n"
89 " %y5 = landingpad i32\n"
90 " cleanup\n"
91 " br label %bb4\n"
92 "bb3:\n"
93 " %y6 = add i32 %x, 1\n"
94 " %y7 = add i32 %x, 1\n"
95 " ret void\n"
96 "bb4:\n"
97 " %y8 = phi i32 [0, %bb2], [%y4, %bb1]\n"
98 " %y9 = phi i32 [0, %bb2], [%y4, %bb1]\n"
99 " ret void\n"
100 "}\n";
101
102 // Parse the module.
103 LLVMContext Context;
104 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
105
106 runWithDomTree(
107 *M, "f", [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
108 Function::iterator FI = F.begin();
109
110 BasicBlock *BB0 = &*FI++;
111 BasicBlock::iterator BBI = BB0->begin();
112 Instruction *Y1 = &*BBI++;
113 Instruction *Y2 = &*BBI++;
114 Instruction *Y3 = &*BBI++;
115
116 BasicBlock *BB1 = &*FI++;
117 BBI = BB1->begin();
118 Instruction *Y4 = &*BBI++;
119
120 BasicBlock *BB2 = &*FI++;
121 BBI = BB2->begin();
122 Instruction *Y5 = &*BBI++;
123
124 BasicBlock *BB3 = &*FI++;
125 BBI = BB3->begin();
126 Instruction *Y6 = &*BBI++;
127 Instruction *Y7 = &*BBI++;
128
129 BasicBlock *BB4 = &*FI++;
130 BBI = BB4->begin();
131 Instruction *Y8 = &*BBI++;
132 Instruction *Y9 = &*BBI++;
133
134 // Reachability
135 EXPECT_TRUE(DT->isReachableFromEntry(BB0));
136 EXPECT_TRUE(DT->isReachableFromEntry(BB1));
137 EXPECT_TRUE(DT->isReachableFromEntry(BB2));
138 EXPECT_FALSE(DT->isReachableFromEntry(BB3));
139 EXPECT_TRUE(DT->isReachableFromEntry(BB4));
140
141 // BB dominance
142 EXPECT_TRUE(DT->dominates(BB0, BB0));
143 EXPECT_TRUE(DT->dominates(BB0, BB1));
144 EXPECT_TRUE(DT->dominates(BB0, BB2));
145 EXPECT_TRUE(DT->dominates(BB0, BB3));
146 EXPECT_TRUE(DT->dominates(BB0, BB4));
147
148 EXPECT_FALSE(DT->dominates(BB1, BB0));
149 EXPECT_TRUE(DT->dominates(BB1, BB1));
150 EXPECT_FALSE(DT->dominates(BB1, BB2));
151 EXPECT_TRUE(DT->dominates(BB1, BB3));
152 EXPECT_FALSE(DT->dominates(BB1, BB4));
153
154 EXPECT_FALSE(DT->dominates(BB2, BB0));
155 EXPECT_FALSE(DT->dominates(BB2, BB1));
156 EXPECT_TRUE(DT->dominates(BB2, BB2));
157 EXPECT_TRUE(DT->dominates(BB2, BB3));
158 EXPECT_FALSE(DT->dominates(BB2, BB4));
159
160 EXPECT_FALSE(DT->dominates(BB3, BB0));
161 EXPECT_FALSE(DT->dominates(BB3, BB1));
162 EXPECT_FALSE(DT->dominates(BB3, BB2));
163 EXPECT_TRUE(DT->dominates(BB3, BB3));
164 EXPECT_FALSE(DT->dominates(BB3, BB4));
165
166 // BB proper dominance
167 EXPECT_FALSE(DT->properlyDominates(BB0, BB0));
168 EXPECT_TRUE(DT->properlyDominates(BB0, BB1));
169 EXPECT_TRUE(DT->properlyDominates(BB0, BB2));
170 EXPECT_TRUE(DT->properlyDominates(BB0, BB3));
171
172 EXPECT_FALSE(DT->properlyDominates(BB1, BB0));
173 EXPECT_FALSE(DT->properlyDominates(BB1, BB1));
174 EXPECT_FALSE(DT->properlyDominates(BB1, BB2));
175 EXPECT_TRUE(DT->properlyDominates(BB1, BB3));
176
177 EXPECT_FALSE(DT->properlyDominates(BB2, BB0));
178 EXPECT_FALSE(DT->properlyDominates(BB2, BB1));
179 EXPECT_FALSE(DT->properlyDominates(BB2, BB2));
180 EXPECT_TRUE(DT->properlyDominates(BB2, BB3));
181
182 EXPECT_FALSE(DT->properlyDominates(BB3, BB0));
183 EXPECT_FALSE(DT->properlyDominates(BB3, BB1));
184 EXPECT_FALSE(DT->properlyDominates(BB3, BB2));
185 EXPECT_FALSE(DT->properlyDominates(BB3, BB3));
186
187 // Instruction dominance in the same reachable BB
188 EXPECT_FALSE(DT->dominates(Y1, Y1));
189 EXPECT_TRUE(DT->dominates(Y1, Y2));
190 EXPECT_FALSE(DT->dominates(Y2, Y1));
191 EXPECT_FALSE(DT->dominates(Y2, Y2));
192
193 // Instruction dominance in the same unreachable BB
194 EXPECT_TRUE(DT->dominates(Y6, Y6));
195 EXPECT_TRUE(DT->dominates(Y6, Y7));
196 EXPECT_TRUE(DT->dominates(Y7, Y6));
197 EXPECT_TRUE(DT->dominates(Y7, Y7));
198
199 // Invoke
200 EXPECT_TRUE(DT->dominates(Y3, Y4));
201 EXPECT_FALSE(DT->dominates(Y3, Y5));
202
203 // Phi
204 EXPECT_TRUE(DT->dominates(Y2, Y9));
205 EXPECT_FALSE(DT->dominates(Y3, Y9));
206 EXPECT_FALSE(DT->dominates(Y8, Y9));
207
208 // Anything dominates unreachable
209 EXPECT_TRUE(DT->dominates(Y1, Y6));
210 EXPECT_TRUE(DT->dominates(Y3, Y6));
211
212 // Unreachable doesn't dominate reachable
213 EXPECT_FALSE(DT->dominates(Y6, Y1));
214
215 // Instruction, BB dominance
216 EXPECT_FALSE(DT->dominates(Y1, BB0));
217 EXPECT_TRUE(DT->dominates(Y1, BB1));
218 EXPECT_TRUE(DT->dominates(Y1, BB2));
219 EXPECT_TRUE(DT->dominates(Y1, BB3));
220 EXPECT_TRUE(DT->dominates(Y1, BB4));
221
222 EXPECT_FALSE(DT->dominates(Y3, BB0));
223 EXPECT_TRUE(DT->dominates(Y3, BB1));
224 EXPECT_FALSE(DT->dominates(Y3, BB2));
225 EXPECT_TRUE(DT->dominates(Y3, BB3));
226 EXPECT_FALSE(DT->dominates(Y3, BB4));
227
228 EXPECT_TRUE(DT->dominates(Y6, BB3));
229
230 // Post dominance.
231 EXPECT_TRUE(PDT->dominates(BB0, BB0));
232 EXPECT_FALSE(PDT->dominates(BB1, BB0));
233 EXPECT_FALSE(PDT->dominates(BB2, BB0));
234 EXPECT_FALSE(PDT->dominates(BB3, BB0));
235 EXPECT_TRUE(PDT->dominates(BB4, BB1));
236
237 // Dominance descendants.
238 SmallVector<BasicBlock *, 8> DominatedBBs, PostDominatedBBs;
239
240 DT->getDescendants(BB0, DominatedBBs);
241 PDT->getDescendants(BB0, PostDominatedBBs);
242 EXPECT_EQ(DominatedBBs.size(), 4UL);
243 EXPECT_EQ(PostDominatedBBs.size(), 1UL);
244
245 // BB3 is unreachable. It should have no dominators nor postdominators.
246 DominatedBBs.clear();
247 PostDominatedBBs.clear();
248 DT->getDescendants(BB3, DominatedBBs);
249 DT->getDescendants(BB3, PostDominatedBBs);
250 EXPECT_EQ(DominatedBBs.size(), 0UL);
251 EXPECT_EQ(PostDominatedBBs.size(), 0UL);
252
253 // Check DFS Numbers before
254 DT->updateDFSNumbers();
255 EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
256 EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 7UL);
257 EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
258 EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 2UL);
259 EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 5UL);
260 EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 6UL);
261 EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 3UL);
262 EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 4UL);
263
264 // Check levels before
265 EXPECT_EQ(DT->getNode(BB0)->getLevel(), 0U);
266 EXPECT_EQ(DT->getNode(BB1)->getLevel(), 1U);
267 EXPECT_EQ(DT->getNode(BB2)->getLevel(), 1U);
268 EXPECT_EQ(DT->getNode(BB4)->getLevel(), 1U);
269
270 // Reattach block 3 to block 1 and recalculate
271 BB1->getTerminator()->eraseFromParent();
272 BranchInst::Create(BB4, BB3, ConstantInt::getTrue(F.getContext()), BB1);
273 DT->recalculate(F);
274
275 // Check DFS Numbers after
276 DT->updateDFSNumbers();
277 EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
278 EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 9UL);
279 EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
280 EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 4UL);
281 EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 7UL);
282 EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 8UL);
283 EXPECT_EQ(DT->getNode(BB3)->getDFSNumIn(), 2UL);
284 EXPECT_EQ(DT->getNode(BB3)->getDFSNumOut(), 3UL);
285 EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 5UL);
286 EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 6UL);
287
288 // Check levels after
289 EXPECT_EQ(DT->getNode(BB0)->getLevel(), 0U);
290 EXPECT_EQ(DT->getNode(BB1)->getLevel(), 1U);
291 EXPECT_EQ(DT->getNode(BB2)->getLevel(), 1U);
292 EXPECT_EQ(DT->getNode(BB3)->getLevel(), 2U);
293 EXPECT_EQ(DT->getNode(BB4)->getLevel(), 1U);
294
295 // Change root node
296 EXPECT_TRUE(DT->verify());
297 BasicBlock *NewEntry =
298 BasicBlock::Create(F.getContext(), "new_entry", &F, BB0);
299 BranchInst::Create(BB0, NewEntry);
300 EXPECT_EQ(F.begin()->getName(), NewEntry->getName());
301 EXPECT_TRUE(&F.getEntryBlock() == NewEntry);
302 DT->setNewRoot(NewEntry);
303 EXPECT_TRUE(DT->verify());
304 });
305 }
306
TEST(DominatorTree,NonUniqueEdges)307 TEST(DominatorTree, NonUniqueEdges) {
308 StringRef ModuleString =
309 "define i32 @f(i32 %i, i32 *%p) {\n"
310 "bb0:\n"
311 " store i32 %i, i32 *%p\n"
312 " switch i32 %i, label %bb2 [\n"
313 " i32 0, label %bb1\n"
314 " i32 1, label %bb1\n"
315 " ]\n"
316 " bb1:\n"
317 " ret i32 1\n"
318 " bb2:\n"
319 " ret i32 4\n"
320 "}\n";
321
322 // Parse the module.
323 LLVMContext Context;
324 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
325
326 runWithDomTree(
327 *M, "f", [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
328 Function::iterator FI = F.begin();
329
330 BasicBlock *BB0 = &*FI++;
331 BasicBlock *BB1 = &*FI++;
332 BasicBlock *BB2 = &*FI++;
333
334 const Instruction *TI = BB0->getTerminator();
335 assert(TI->getNumSuccessors() == 3 && "Switch has three successors");
336
337 BasicBlockEdge Edge_BB0_BB2(BB0, TI->getSuccessor(0));
338 assert(Edge_BB0_BB2.getEnd() == BB2 &&
339 "Default label is the 1st successor");
340
341 BasicBlockEdge Edge_BB0_BB1_a(BB0, TI->getSuccessor(1));
342 assert(Edge_BB0_BB1_a.getEnd() == BB1 && "BB1 is the 2nd successor");
343
344 BasicBlockEdge Edge_BB0_BB1_b(BB0, TI->getSuccessor(2));
345 assert(Edge_BB0_BB1_b.getEnd() == BB1 && "BB1 is the 3rd successor");
346
347 EXPECT_TRUE(DT->dominates(Edge_BB0_BB2, BB2));
348 EXPECT_FALSE(DT->dominates(Edge_BB0_BB2, BB1));
349
350 EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_a, BB1));
351 EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_b, BB1));
352
353 EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_a, BB2));
354 EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_b, BB2));
355 });
356 }
357
358 // Verify that the PDT is correctly updated in case an edge removal results
359 // in a new unreachable CFG node. Also make sure that the updated PDT is the
360 // same as a freshly recalculated one.
361 //
362 // For the following input code and initial PDT:
363 //
364 // CFG PDT
365 //
366 // A Exit
367 // | |
368 // _B D
369 // / | \ |
370 // ^ v \ B
371 // \ / D / \
372 // C \ C A
373 // v
374 // Exit
375 //
376 // we verify that CFG' and PDT-updated is obtained after removal of edge C -> B.
377 //
378 // CFG' PDT-updated
379 //
380 // A Exit
381 // | / | \
382 // B C B D
383 // | \ |
384 // v \ A
385 // / D
386 // C \
387 // | \
388 // unreachable Exit
389 //
390 // Both the blocks that end with ret and with unreachable become trivial
391 // PostDominatorTree roots, as they have no successors.
392 //
TEST(DominatorTree,DeletingEdgesIntroducesUnreachables)393 TEST(DominatorTree, DeletingEdgesIntroducesUnreachables) {
394 StringRef ModuleString =
395 "define void @f() {\n"
396 "A:\n"
397 " br label %B\n"
398 "B:\n"
399 " br i1 undef, label %D, label %C\n"
400 "C:\n"
401 " br label %B\n"
402 "D:\n"
403 " ret void\n"
404 "}\n";
405
406 // Parse the module.
407 LLVMContext Context;
408 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
409
410 runWithDomTree(
411 *M, "f", [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
412 Function::iterator FI = F.begin();
413
414 FI++;
415 BasicBlock *B = &*FI++;
416 BasicBlock *C = &*FI++;
417 BasicBlock *D = &*FI++;
418
419 ASSERT_TRUE(PDT->dominates(PDT->getNode(D), PDT->getNode(B)));
420 EXPECT_TRUE(DT->verify());
421 EXPECT_TRUE(PDT->verify());
422
423 C->getTerminator()->eraseFromParent();
424 new UnreachableInst(C->getContext(), C);
425
426 DT->deleteEdge(C, B);
427 PDT->deleteEdge(C, B);
428
429 EXPECT_TRUE(DT->verify());
430 EXPECT_TRUE(PDT->verify());
431
432 EXPECT_FALSE(PDT->dominates(PDT->getNode(D), PDT->getNode(B)));
433 EXPECT_NE(PDT->getNode(C), nullptr);
434
435 DominatorTree NDT(F);
436 EXPECT_EQ(DT->compare(NDT), 0);
437
438 PostDominatorTree NPDT(F);
439 EXPECT_EQ(PDT->compare(NPDT), 0);
440 });
441 }
442
443 // Verify that the PDT is correctly updated in case an edge removal results
444 // in an infinite loop. Also make sure that the updated PDT is the
445 // same as a freshly recalculated one.
446 //
447 // Test case:
448 //
449 // CFG PDT
450 //
451 // A Exit
452 // | |
453 // _B D
454 // / | \ |
455 // ^ v \ B
456 // \ / D / \
457 // C \ C A
458 // / \ v
459 // ^ v Exit
460 // \_/
461 //
462 // After deleting the edge C->B, C is part of an infinite reverse-unreachable
463 // loop:
464 //
465 // CFG' PDT'
466 //
467 // A Exit
468 // | / | \
469 // B C B D
470 // | \ |
471 // v \ A
472 // / D
473 // C \
474 // / \ v
475 // ^ v Exit
476 // \_/
477 //
478 // As C now becomes reverse-unreachable, it forms a new non-trivial root and
479 // gets connected to the virtual exit.
480 // D does not postdominate B anymore, because there are two forward paths from
481 // B to the virtual exit:
482 // - B -> C -> VirtualExit
483 // - B -> D -> VirtualExit.
484 //
TEST(DominatorTree,DeletingEdgesIntroducesInfiniteLoop)485 TEST(DominatorTree, DeletingEdgesIntroducesInfiniteLoop) {
486 StringRef ModuleString =
487 "define void @f() {\n"
488 "A:\n"
489 " br label %B\n"
490 "B:\n"
491 " br i1 undef, label %D, label %C\n"
492 "C:\n"
493 " switch i32 undef, label %C [\n"
494 " i32 0, label %B\n"
495 " ]\n"
496 "D:\n"
497 " ret void\n"
498 "}\n";
499
500 // Parse the module.
501 LLVMContext Context;
502 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
503
504 runWithDomTree(
505 *M, "f", [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
506 Function::iterator FI = F.begin();
507
508 FI++;
509 BasicBlock *B = &*FI++;
510 BasicBlock *C = &*FI++;
511 BasicBlock *D = &*FI++;
512
513 ASSERT_TRUE(PDT->dominates(PDT->getNode(D), PDT->getNode(B)));
514 EXPECT_TRUE(DT->verify());
515 EXPECT_TRUE(PDT->verify());
516
517 auto SwitchC = cast<SwitchInst>(C->getTerminator());
518 SwitchC->removeCase(SwitchC->case_begin());
519 DT->deleteEdge(C, B);
520 EXPECT_TRUE(DT->verify());
521 PDT->deleteEdge(C, B);
522 EXPECT_TRUE(PDT->verify());
523
524 EXPECT_FALSE(PDT->dominates(PDT->getNode(D), PDT->getNode(B)));
525 EXPECT_NE(PDT->getNode(C), nullptr);
526
527 DominatorTree NDT(F);
528 EXPECT_EQ(DT->compare(NDT), 0);
529
530 PostDominatorTree NPDT(F);
531 EXPECT_EQ(PDT->compare(NPDT), 0);
532 });
533 }
534
535 // Verify that the PDT is correctly updated in case an edge removal results
536 // in an infinite loop.
537 //
538 // Test case:
539 //
540 // CFG PDT
541 //
542 // A Exit
543 // | / | \
544 // B-- C2 B D
545 // | \ / |
546 // v \ C A
547 // / D
548 // C--C2 \
549 // / \ \ v
550 // ^ v --Exit
551 // \_/
552 //
553 // After deleting the edge C->E, C is part of an infinite reverse-unreachable
554 // loop:
555 //
556 // CFG' PDT'
557 //
558 // A Exit
559 // | / | \
560 // B C B D
561 // | \ |
562 // v \ A
563 // / D
564 // C \
565 // / \ v
566 // ^ v Exit
567 // \_/
568 //
569 // In PDT, D does not post-dominate B. After the edge C -> C2 is removed,
570 // C becomes a new nontrivial PDT root.
571 //
TEST(DominatorTree,DeletingEdgesIntroducesInfiniteLoop2)572 TEST(DominatorTree, DeletingEdgesIntroducesInfiniteLoop2) {
573 StringRef ModuleString =
574 "define void @f() {\n"
575 "A:\n"
576 " br label %B\n"
577 "B:\n"
578 " br i1 undef, label %D, label %C\n"
579 "C:\n"
580 " switch i32 undef, label %C [\n"
581 " i32 0, label %C2\n"
582 " ]\n"
583 "C2:\n"
584 " ret void\n"
585 "D:\n"
586 " ret void\n"
587 "}\n";
588
589 // Parse the module.
590 LLVMContext Context;
591 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
592
593 runWithDomTree(
594 *M, "f", [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
595 Function::iterator FI = F.begin();
596
597 FI++;
598 BasicBlock *B = &*FI++;
599 BasicBlock *C = &*FI++;
600 BasicBlock *C2 = &*FI++;
601 BasicBlock *D = &*FI++;
602
603 EXPECT_TRUE(DT->verify());
604 EXPECT_TRUE(PDT->verify());
605
606 auto SwitchC = cast<SwitchInst>(C->getTerminator());
607 SwitchC->removeCase(SwitchC->case_begin());
608 DT->deleteEdge(C, C2);
609 PDT->deleteEdge(C, C2);
610 C2->removeFromParent();
611
612 EXPECT_EQ(DT->getNode(C2), nullptr);
613 PDT->eraseNode(C2);
614 delete C2;
615
616 EXPECT_TRUE(DT->verify());
617 EXPECT_TRUE(PDT->verify());
618
619 EXPECT_FALSE(PDT->dominates(PDT->getNode(D), PDT->getNode(B)));
620 EXPECT_NE(PDT->getNode(C), nullptr);
621
622 DominatorTree NDT(F);
623 EXPECT_EQ(DT->compare(NDT), 0);
624
625 PostDominatorTree NPDT(F);
626 EXPECT_EQ(PDT->compare(NPDT), 0);
627 });
628 }
629
630 // Verify that the IDF returns blocks in a deterministic way.
631 //
632 // Test case:
633 //
634 // CFG
635 //
636 // (A)
637 // / \
638 // / \
639 // (B) (C)
640 // |\ /|
641 // | X |
642 // |/ \|
643 // (D) (E)
644 //
645 // IDF for block B is {D, E}, and the order of blocks in this list is defined by
646 // their 1) level in dom-tree and 2) DFSIn number if the level is the same.
647 //
TEST(DominatorTree,IDFDeterminismTest)648 TEST(DominatorTree, IDFDeterminismTest) {
649 StringRef ModuleString =
650 "define void @f() {\n"
651 "A:\n"
652 " br i1 undef, label %B, label %C\n"
653 "B:\n"
654 " br i1 undef, label %D, label %E\n"
655 "C:\n"
656 " br i1 undef, label %D, label %E\n"
657 "D:\n"
658 " ret void\n"
659 "E:\n"
660 " ret void\n"
661 "}\n";
662
663 // Parse the module.
664 LLVMContext Context;
665 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
666
667 runWithDomTree(
668 *M, "f", [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
669 Function::iterator FI = F.begin();
670
671 BasicBlock *A = &*FI++;
672 BasicBlock *B = &*FI++;
673 BasicBlock *C = &*FI++;
674 BasicBlock *D = &*FI++;
675 BasicBlock *E = &*FI++;
676 (void)C;
677
678 DT->updateDFSNumbers();
679 ForwardIDFCalculator IDF(*DT);
680 SmallPtrSet<BasicBlock *, 1> DefBlocks;
681 DefBlocks.insert(B);
682 IDF.setDefiningBlocks(DefBlocks);
683
684 SmallVector<BasicBlock *, 32> IDFBlocks;
685 SmallPtrSet<BasicBlock *, 32> LiveInBlocks;
686 IDF.resetLiveInBlocks();
687 IDF.calculate(IDFBlocks);
688
689
690 EXPECT_EQ(IDFBlocks.size(), 2UL);
691 EXPECT_EQ(DT->getNode(A)->getDFSNumIn(), 0UL);
692 EXPECT_EQ(IDFBlocks[0], D);
693 EXPECT_EQ(IDFBlocks[1], E);
694 EXPECT_TRUE(DT->getNode(IDFBlocks[0])->getDFSNumIn() <
695 DT->getNode(IDFBlocks[1])->getDFSNumIn());
696 });
697 }
698
699 namespace {
700 const auto Insert = CFGBuilder::ActionKind::Insert;
701 const auto Delete = CFGBuilder::ActionKind::Delete;
702
CompUpdates(const CFGBuilder::Update & A,const CFGBuilder::Update & B)703 bool CompUpdates(const CFGBuilder::Update &A, const CFGBuilder::Update &B) {
704 return std::tie(A.Action, A.Edge.From, A.Edge.To) <
705 std::tie(B.Action, B.Edge.From, B.Edge.To);
706 }
707 } // namespace
708
TEST(DominatorTree,InsertReachable)709 TEST(DominatorTree, InsertReachable) {
710 CFGHolder Holder;
711 std::vector<CFGBuilder::Arc> Arcs = {
712 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"4", "5"}, {"5", "6"}, {"5", "7"},
713 {"3", "8"}, {"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}};
714
715 std::vector<CFGBuilder::Update> Updates = {{Insert, {"12", "10"}},
716 {Insert, {"10", "9"}},
717 {Insert, {"7", "6"}},
718 {Insert, {"7", "5"}}};
719 CFGBuilder B(Holder.F, Arcs, Updates);
720 DominatorTree DT(*Holder.F);
721 EXPECT_TRUE(DT.verify());
722 PostDominatorTree PDT(*Holder.F);
723 EXPECT_TRUE(PDT.verify());
724
725 Optional<CFGBuilder::Update> LastUpdate;
726 while ((LastUpdate = B.applyUpdate())) {
727 EXPECT_EQ(LastUpdate->Action, Insert);
728 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
729 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
730 DT.insertEdge(From, To);
731 EXPECT_TRUE(DT.verify());
732 PDT.insertEdge(From, To);
733 EXPECT_TRUE(PDT.verify());
734 }
735 }
736
TEST(DominatorTree,InsertReachable2)737 TEST(DominatorTree, InsertReachable2) {
738 CFGHolder Holder;
739 std::vector<CFGBuilder::Arc> Arcs = {
740 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"4", "5"}, {"5", "6"}, {"5", "7"},
741 {"7", "5"}, {"2", "8"}, {"8", "11"}, {"11", "12"}, {"12", "10"},
742 {"10", "9"}, {"9", "10"}};
743
744 std::vector<CFGBuilder::Update> Updates = {{Insert, {"10", "7"}}};
745 CFGBuilder B(Holder.F, Arcs, Updates);
746 DominatorTree DT(*Holder.F);
747 EXPECT_TRUE(DT.verify());
748 PostDominatorTree PDT(*Holder.F);
749 EXPECT_TRUE(PDT.verify());
750
751 Optional<CFGBuilder::Update> LastUpdate = B.applyUpdate();
752 EXPECT_TRUE(LastUpdate);
753
754 EXPECT_EQ(LastUpdate->Action, Insert);
755 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
756 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
757 DT.insertEdge(From, To);
758 EXPECT_TRUE(DT.verify());
759 PDT.insertEdge(From, To);
760 EXPECT_TRUE(PDT.verify());
761 }
762
TEST(DominatorTree,InsertUnreachable)763 TEST(DominatorTree, InsertUnreachable) {
764 CFGHolder Holder;
765 std::vector<CFGBuilder::Arc> Arcs = {{"1", "2"}, {"2", "3"}, {"3", "4"},
766 {"5", "6"}, {"5", "7"}, {"3", "8"},
767 {"9", "10"}, {"11", "12"}};
768
769 std::vector<CFGBuilder::Update> Updates = {{Insert, {"4", "5"}},
770 {Insert, {"8", "9"}},
771 {Insert, {"10", "12"}},
772 {Insert, {"10", "11"}}};
773 CFGBuilder B(Holder.F, Arcs, Updates);
774 DominatorTree DT(*Holder.F);
775 EXPECT_TRUE(DT.verify());
776 PostDominatorTree PDT(*Holder.F);
777 EXPECT_TRUE(PDT.verify());
778
779 Optional<CFGBuilder::Update> LastUpdate;
780 while ((LastUpdate = B.applyUpdate())) {
781 EXPECT_EQ(LastUpdate->Action, Insert);
782 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
783 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
784 DT.insertEdge(From, To);
785 EXPECT_TRUE(DT.verify());
786 PDT.insertEdge(From, To);
787 EXPECT_TRUE(PDT.verify());
788 }
789 }
790
TEST(DominatorTree,InsertFromUnreachable)791 TEST(DominatorTree, InsertFromUnreachable) {
792 CFGHolder Holder;
793 std::vector<CFGBuilder::Arc> Arcs = {{"1", "2"}, {"2", "3"}, {"3", "4"}};
794
795 std::vector<CFGBuilder::Update> Updates = {{Insert, {"3", "5"}}};
796 CFGBuilder B(Holder.F, Arcs, Updates);
797 PostDominatorTree PDT(*Holder.F);
798 EXPECT_TRUE(PDT.verify());
799
800 Optional<CFGBuilder::Update> LastUpdate = B.applyUpdate();
801 EXPECT_TRUE(LastUpdate);
802
803 EXPECT_EQ(LastUpdate->Action, Insert);
804 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
805 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
806 PDT.insertEdge(From, To);
807 EXPECT_TRUE(PDT.verify());
808 EXPECT_EQ(PDT.root_size(), 2UL);
809 // Make sure we can use a const pointer with getNode.
810 const BasicBlock *BB5 = B.getOrAddBlock("5");
811 EXPECT_NE(PDT.getNode(BB5), nullptr);
812 }
813
TEST(DominatorTree,InsertMixed)814 TEST(DominatorTree, InsertMixed) {
815 CFGHolder Holder;
816 std::vector<CFGBuilder::Arc> Arcs = {
817 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"5", "6"}, {"5", "7"},
818 {"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}, {"7", "3"}};
819
820 std::vector<CFGBuilder::Update> Updates = {
821 {Insert, {"4", "5"}}, {Insert, {"2", "5"}}, {Insert, {"10", "9"}},
822 {Insert, {"12", "10"}}, {Insert, {"12", "10"}}, {Insert, {"7", "8"}},
823 {Insert, {"7", "5"}}};
824 CFGBuilder B(Holder.F, Arcs, Updates);
825 DominatorTree DT(*Holder.F);
826 EXPECT_TRUE(DT.verify());
827 PostDominatorTree PDT(*Holder.F);
828 EXPECT_TRUE(PDT.verify());
829
830 Optional<CFGBuilder::Update> LastUpdate;
831 while ((LastUpdate = B.applyUpdate())) {
832 EXPECT_EQ(LastUpdate->Action, Insert);
833 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
834 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
835 DT.insertEdge(From, To);
836 EXPECT_TRUE(DT.verify());
837 PDT.insertEdge(From, To);
838 EXPECT_TRUE(PDT.verify());
839 }
840 }
841
TEST(DominatorTree,InsertPermut)842 TEST(DominatorTree, InsertPermut) {
843 std::vector<CFGBuilder::Arc> Arcs = {
844 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"5", "6"}, {"5", "7"},
845 {"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}, {"7", "3"}};
846
847 std::vector<CFGBuilder::Update> Updates = {{Insert, {"4", "5"}},
848 {Insert, {"2", "5"}},
849 {Insert, {"10", "9"}},
850 {Insert, {"12", "10"}}};
851
852 while (std::next_permutation(Updates.begin(), Updates.end(), CompUpdates)) {
853 CFGHolder Holder;
854 CFGBuilder B(Holder.F, Arcs, Updates);
855 DominatorTree DT(*Holder.F);
856 EXPECT_TRUE(DT.verify());
857 PostDominatorTree PDT(*Holder.F);
858 EXPECT_TRUE(PDT.verify());
859
860 Optional<CFGBuilder::Update> LastUpdate;
861 while ((LastUpdate = B.applyUpdate())) {
862 EXPECT_EQ(LastUpdate->Action, Insert);
863 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
864 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
865 DT.insertEdge(From, To);
866 EXPECT_TRUE(DT.verify());
867 PDT.insertEdge(From, To);
868 EXPECT_TRUE(PDT.verify());
869 }
870 }
871 }
872
TEST(DominatorTree,DeleteReachable)873 TEST(DominatorTree, DeleteReachable) {
874 CFGHolder Holder;
875 std::vector<CFGBuilder::Arc> Arcs = {
876 {"1", "2"}, {"2", "3"}, {"2", "4"}, {"3", "4"}, {"4", "5"}, {"5", "6"},
877 {"5", "7"}, {"7", "8"}, {"3", "8"}, {"8", "9"}, {"9", "10"}, {"10", "2"}};
878
879 std::vector<CFGBuilder::Update> Updates = {
880 {Delete, {"2", "4"}}, {Delete, {"7", "8"}}, {Delete, {"10", "2"}}};
881 CFGBuilder B(Holder.F, Arcs, Updates);
882 DominatorTree DT(*Holder.F);
883 EXPECT_TRUE(DT.verify());
884 PostDominatorTree PDT(*Holder.F);
885 EXPECT_TRUE(PDT.verify());
886
887 Optional<CFGBuilder::Update> LastUpdate;
888 while ((LastUpdate = B.applyUpdate())) {
889 EXPECT_EQ(LastUpdate->Action, Delete);
890 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
891 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
892 DT.deleteEdge(From, To);
893 EXPECT_TRUE(DT.verify());
894 PDT.deleteEdge(From, To);
895 EXPECT_TRUE(PDT.verify());
896 }
897 }
898
TEST(DominatorTree,DeleteUnreachable)899 TEST(DominatorTree, DeleteUnreachable) {
900 CFGHolder Holder;
901 std::vector<CFGBuilder::Arc> Arcs = {
902 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"4", "5"}, {"5", "6"}, {"5", "7"},
903 {"7", "8"}, {"3", "8"}, {"8", "9"}, {"9", "10"}, {"10", "2"}};
904
905 std::vector<CFGBuilder::Update> Updates = {
906 {Delete, {"8", "9"}}, {Delete, {"7", "8"}}, {Delete, {"3", "4"}}};
907 CFGBuilder B(Holder.F, Arcs, Updates);
908 DominatorTree DT(*Holder.F);
909 EXPECT_TRUE(DT.verify());
910 PostDominatorTree PDT(*Holder.F);
911 EXPECT_TRUE(PDT.verify());
912
913 Optional<CFGBuilder::Update> LastUpdate;
914 while ((LastUpdate = B.applyUpdate())) {
915 EXPECT_EQ(LastUpdate->Action, Delete);
916 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
917 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
918 DT.deleteEdge(From, To);
919 EXPECT_TRUE(DT.verify());
920 PDT.deleteEdge(From, To);
921 EXPECT_TRUE(PDT.verify());
922 }
923 }
924
TEST(DominatorTree,InsertDelete)925 TEST(DominatorTree, InsertDelete) {
926 std::vector<CFGBuilder::Arc> Arcs = {
927 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"4", "5"}, {"5", "6"}, {"5", "7"},
928 {"3", "8"}, {"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}};
929
930 std::vector<CFGBuilder::Update> Updates = {
931 {Insert, {"2", "4"}}, {Insert, {"12", "10"}}, {Insert, {"10", "9"}},
932 {Insert, {"7", "6"}}, {Insert, {"7", "5"}}, {Delete, {"3", "8"}},
933 {Insert, {"10", "7"}}, {Insert, {"2", "8"}}, {Delete, {"3", "4"}},
934 {Delete, {"8", "9"}}, {Delete, {"11", "12"}}};
935
936 CFGHolder Holder;
937 CFGBuilder B(Holder.F, Arcs, Updates);
938 DominatorTree DT(*Holder.F);
939 EXPECT_TRUE(DT.verify());
940 PostDominatorTree PDT(*Holder.F);
941 EXPECT_TRUE(PDT.verify());
942
943 Optional<CFGBuilder::Update> LastUpdate;
944 while ((LastUpdate = B.applyUpdate())) {
945 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
946 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
947 if (LastUpdate->Action == Insert) {
948 DT.insertEdge(From, To);
949 PDT.insertEdge(From, To);
950 } else {
951 DT.deleteEdge(From, To);
952 PDT.deleteEdge(From, To);
953 }
954
955 EXPECT_TRUE(DT.verify());
956 EXPECT_TRUE(PDT.verify());
957 }
958 }
959
TEST(DominatorTree,InsertDeleteExhaustive)960 TEST(DominatorTree, InsertDeleteExhaustive) {
961 std::vector<CFGBuilder::Arc> Arcs = {
962 {"1", "2"}, {"2", "3"}, {"3", "4"}, {"4", "5"}, {"5", "6"}, {"5", "7"},
963 {"3", "8"}, {"8", "9"}, {"9", "10"}, {"8", "11"}, {"11", "12"}};
964
965 std::vector<CFGBuilder::Update> Updates = {
966 {Insert, {"2", "4"}}, {Insert, {"12", "10"}}, {Insert, {"10", "9"}},
967 {Insert, {"7", "6"}}, {Insert, {"7", "5"}}, {Delete, {"3", "8"}},
968 {Insert, {"10", "7"}}, {Insert, {"2", "8"}}, {Delete, {"3", "4"}},
969 {Delete, {"8", "9"}}, {Delete, {"11", "12"}}};
970
971 std::mt19937 Generator(0);
972 for (unsigned i = 0; i < 16; ++i) {
973 std::shuffle(Updates.begin(), Updates.end(), Generator);
974 CFGHolder Holder;
975 CFGBuilder B(Holder.F, Arcs, Updates);
976 DominatorTree DT(*Holder.F);
977 EXPECT_TRUE(DT.verify());
978 PostDominatorTree PDT(*Holder.F);
979 EXPECT_TRUE(PDT.verify());
980
981 Optional<CFGBuilder::Update> LastUpdate;
982 while ((LastUpdate = B.applyUpdate())) {
983 BasicBlock *From = B.getOrAddBlock(LastUpdate->Edge.From);
984 BasicBlock *To = B.getOrAddBlock(LastUpdate->Edge.To);
985 if (LastUpdate->Action == Insert) {
986 DT.insertEdge(From, To);
987 PDT.insertEdge(From, To);
988 } else {
989 DT.deleteEdge(From, To);
990 PDT.deleteEdge(From, To);
991 }
992
993 EXPECT_TRUE(DT.verify());
994 EXPECT_TRUE(PDT.verify());
995 }
996 }
997 }
998
TEST(DominatorTree,InsertIntoIrreducible)999 TEST(DominatorTree, InsertIntoIrreducible) {
1000 std::vector<CFGBuilder::Arc> Arcs = {
1001 {"0", "1"},
1002 {"1", "27"}, {"1", "7"},
1003 {"10", "18"},
1004 {"13", "10"},
1005 {"18", "13"}, {"18", "23"},
1006 {"23", "13"}, {"23", "24"},
1007 {"24", "1"}, {"24", "18"},
1008 {"27", "24"}};
1009
1010 CFGHolder Holder;
1011 CFGBuilder B(Holder.F, Arcs, {{Insert, {"7", "23"}}});
1012 DominatorTree DT(*Holder.F);
1013 EXPECT_TRUE(DT.verify());
1014
1015 B.applyUpdate();
1016 BasicBlock *From = B.getOrAddBlock("7");
1017 BasicBlock *To = B.getOrAddBlock("23");
1018 DT.insertEdge(From, To);
1019
1020 EXPECT_TRUE(DT.verify());
1021 }
1022
TEST(DominatorTree,EdgeDomination)1023 TEST(DominatorTree, EdgeDomination) {
1024 StringRef ModuleString = "define i32 @f(i1 %cond) {\n"
1025 " bb0:\n"
1026 " br i1 %cond, label %bb1, label %bb2\n"
1027 " bb1:\n"
1028 " br label %bb3\n"
1029 " bb2:\n"
1030 " br label %bb3\n"
1031 " bb3:\n"
1032 " ret i32 4"
1033 "}\n";
1034
1035 // Parse the module.
1036 LLVMContext Context;
1037 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
1038
1039 runWithDomTree(*M, "f",
1040 [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
1041 Function::iterator FI = F.begin();
1042
1043 BasicBlock *BB0 = &*FI++;
1044 BasicBlock *BB1 = &*FI++;
1045 BasicBlock *BB2 = &*FI++;
1046 BasicBlock *BB3 = &*FI++;
1047
1048 BasicBlockEdge E01(BB0, BB1);
1049 BasicBlockEdge E02(BB0, BB2);
1050 BasicBlockEdge E13(BB1, BB3);
1051 BasicBlockEdge E23(BB2, BB3);
1052
1053 EXPECT_TRUE(DT->dominates(E01, E01));
1054 EXPECT_FALSE(DT->dominates(E01, E02));
1055 EXPECT_TRUE(DT->dominates(E01, E13));
1056 EXPECT_FALSE(DT->dominates(E01, E23));
1057
1058 EXPECT_FALSE(DT->dominates(E02, E01));
1059 EXPECT_TRUE(DT->dominates(E02, E02));
1060 EXPECT_FALSE(DT->dominates(E02, E13));
1061 EXPECT_TRUE(DT->dominates(E02, E23));
1062
1063 EXPECT_FALSE(DT->dominates(E13, E01));
1064 EXPECT_FALSE(DT->dominates(E13, E02));
1065 EXPECT_TRUE(DT->dominates(E13, E13));
1066 EXPECT_FALSE(DT->dominates(E13, E23));
1067
1068 EXPECT_FALSE(DT->dominates(E23, E01));
1069 EXPECT_FALSE(DT->dominates(E23, E02));
1070 EXPECT_FALSE(DT->dominates(E23, E13));
1071 EXPECT_TRUE(DT->dominates(E23, E23));
1072 });
1073 }
1074
TEST(DominatorTree,ValueDomination)1075 TEST(DominatorTree, ValueDomination) {
1076 StringRef ModuleString = R"(
1077 @foo = global i8 0
1078 define i8 @f(i8 %arg) {
1079 ret i8 %arg
1080 }
1081 )";
1082
1083 LLVMContext Context;
1084 std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
1085
1086 runWithDomTree(*M, "f",
1087 [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
1088 Argument *A = F.getArg(0);
1089 GlobalValue *G = M->getNamedValue("foo");
1090 Constant *C = ConstantInt::getNullValue(Type::getInt8Ty(Context));
1091
1092 Instruction *I = F.getEntryBlock().getTerminator();
1093 EXPECT_TRUE(DT->dominates(A, I));
1094 EXPECT_TRUE(DT->dominates(G, I));
1095 EXPECT_TRUE(DT->dominates(C, I));
1096
1097 const Use &U = I->getOperandUse(0);
1098 EXPECT_TRUE(DT->dominates(A, U));
1099 EXPECT_TRUE(DT->dominates(G, U));
1100 EXPECT_TRUE(DT->dominates(C, U));
1101 });
1102 }
1103