1 //===- Local.cpp - Unit tests for Local -----------------------------------===//
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 "llvm/Transforms/Utils/Local.h"
10 #include "llvm/Analysis/DomTreeUpdater.h"
11 #include "llvm/Analysis/PostDominators.h"
12 #include "llvm/Analysis/TargetTransformInfo.h"
13 #include "llvm/AsmParser/Parser.h"
14 #include "llvm/IR/BasicBlock.h"
15 #include "llvm/IR/DIBuilder.h"
16 #include "llvm/IR/IRBuilder.h"
17 #include "llvm/IR/Instructions.h"
18 #include "llvm/IR/IntrinsicInst.h"
19 #include "llvm/IR/LLVMContext.h"
20 #include "llvm/IR/Verifier.h"
21 #include "llvm/Support/SourceMgr.h"
22 #include "gtest/gtest.h"
23
24 using namespace llvm;
25
TEST(Local,RecursivelyDeleteDeadPHINodes)26 TEST(Local, RecursivelyDeleteDeadPHINodes) {
27 LLVMContext C;
28
29 IRBuilder<> builder(C);
30
31 // Make blocks
32 BasicBlock *bb0 = BasicBlock::Create(C);
33 BasicBlock *bb1 = BasicBlock::Create(C);
34
35 builder.SetInsertPoint(bb0);
36 PHINode *phi = builder.CreatePHI(Type::getInt32Ty(C), 2);
37 BranchInst *br0 = builder.CreateCondBr(builder.getTrue(), bb0, bb1);
38
39 builder.SetInsertPoint(bb1);
40 BranchInst *br1 = builder.CreateBr(bb0);
41
42 phi->addIncoming(phi, bb0);
43 phi->addIncoming(phi, bb1);
44
45 // The PHI will be removed
46 EXPECT_TRUE(RecursivelyDeleteDeadPHINode(phi));
47
48 // Make sure the blocks only contain the branches
49 EXPECT_EQ(&bb0->front(), br0);
50 EXPECT_EQ(&bb1->front(), br1);
51
52 builder.SetInsertPoint(bb0);
53 phi = builder.CreatePHI(Type::getInt32Ty(C), 0);
54
55 EXPECT_TRUE(RecursivelyDeleteDeadPHINode(phi));
56
57 builder.SetInsertPoint(bb0);
58 phi = builder.CreatePHI(Type::getInt32Ty(C), 0);
59 builder.CreateAdd(phi, phi);
60
61 EXPECT_TRUE(RecursivelyDeleteDeadPHINode(phi));
62
63 bb0->dropAllReferences();
64 bb1->dropAllReferences();
65 delete bb0;
66 delete bb1;
67 }
68
TEST(Local,RemoveDuplicatePHINodes)69 TEST(Local, RemoveDuplicatePHINodes) {
70 LLVMContext C;
71 IRBuilder<> B(C);
72
73 std::unique_ptr<Function> F(
74 Function::Create(FunctionType::get(B.getVoidTy(), false),
75 GlobalValue::ExternalLinkage, "F"));
76 BasicBlock *Entry(BasicBlock::Create(C, "", F.get()));
77 BasicBlock *BB(BasicBlock::Create(C, "", F.get()));
78 BranchInst::Create(BB, Entry);
79
80 B.SetInsertPoint(BB);
81
82 AssertingVH<PHINode> P1 = B.CreatePHI(Type::getInt32Ty(C), 2);
83 P1->addIncoming(B.getInt32(42), Entry);
84
85 PHINode *P2 = B.CreatePHI(Type::getInt32Ty(C), 2);
86 P2->addIncoming(B.getInt32(42), Entry);
87
88 AssertingVH<PHINode> P3 = B.CreatePHI(Type::getInt32Ty(C), 2);
89 P3->addIncoming(B.getInt32(42), Entry);
90 P3->addIncoming(B.getInt32(23), BB);
91
92 PHINode *P4 = B.CreatePHI(Type::getInt32Ty(C), 2);
93 P4->addIncoming(B.getInt32(42), Entry);
94 P4->addIncoming(B.getInt32(23), BB);
95
96 P1->addIncoming(P3, BB);
97 P2->addIncoming(P4, BB);
98 BranchInst::Create(BB, BB);
99
100 // Verify that we can eliminate PHIs that become duplicates after chaning PHIs
101 // downstream.
102 EXPECT_TRUE(EliminateDuplicatePHINodes(BB));
103 EXPECT_EQ(3U, BB->size());
104 }
105
parseIR(LLVMContext & C,const char * IR)106 static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
107 SMDiagnostic Err;
108 std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
109 if (!Mod)
110 Err.print("UtilsTests", errs());
111 return Mod;
112 }
113
TEST(Local,ReplaceDbgDeclare)114 TEST(Local, ReplaceDbgDeclare) {
115 LLVMContext C;
116
117 // Original C source to get debug info for a local variable:
118 // void f() { int x; }
119 std::unique_ptr<Module> M = parseIR(C,
120 R"(
121 define void @f() !dbg !8 {
122 entry:
123 %x = alloca i32, align 4
124 call void @llvm.dbg.declare(metadata i32* %x, metadata !11, metadata !DIExpression()), !dbg !13
125 call void @llvm.dbg.declare(metadata i32* %x, metadata !11, metadata !DIExpression()), !dbg !13
126 ret void, !dbg !14
127 }
128 declare void @llvm.dbg.declare(metadata, metadata, metadata)
129 !llvm.dbg.cu = !{!0}
130 !llvm.module.flags = !{!3, !4}
131 !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
132 !1 = !DIFile(filename: "t2.c", directory: "foo")
133 !2 = !{}
134 !3 = !{i32 2, !"Dwarf Version", i32 4}
135 !4 = !{i32 2, !"Debug Info Version", i32 3}
136 !8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !0, retainedNodes: !2)
137 !9 = !DISubroutineType(types: !10)
138 !10 = !{null}
139 !11 = !DILocalVariable(name: "x", scope: !8, file: !1, line: 2, type: !12)
140 !12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
141 !13 = !DILocation(line: 2, column: 7, scope: !8)
142 !14 = !DILocation(line: 3, column: 1, scope: !8)
143 )");
144 auto *GV = M->getNamedValue("f");
145 ASSERT_TRUE(GV);
146 auto *F = dyn_cast<Function>(GV);
147 ASSERT_TRUE(F);
148 Instruction *Inst = &F->front().front();
149 auto *AI = dyn_cast<AllocaInst>(Inst);
150 ASSERT_TRUE(AI);
151 Inst = Inst->getNextNode()->getNextNode();
152 ASSERT_TRUE(Inst);
153 auto *DII = dyn_cast<DbgDeclareInst>(Inst);
154 ASSERT_TRUE(DII);
155 Value *NewBase = Constant::getNullValue(Type::getInt32PtrTy(C));
156 DIBuilder DIB(*M);
157 replaceDbgDeclare(AI, NewBase, DIB, DIExpression::ApplyOffset, 0);
158
159 // There should be exactly two dbg.declares.
160 int Declares = 0;
161 for (const Instruction &I : F->front())
162 if (isa<DbgDeclareInst>(I))
163 Declares++;
164 EXPECT_EQ(2, Declares);
165 }
166
167 /// Build the dominator tree for the function and run the Test.
runWithDomTree(Module & M,StringRef FuncName,function_ref<void (Function & F,DominatorTree * DT)> Test)168 static void runWithDomTree(
169 Module &M, StringRef FuncName,
170 function_ref<void(Function &F, DominatorTree *DT)> Test) {
171 auto *F = M.getFunction(FuncName);
172 ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
173 // Compute the dominator tree for the function.
174 DominatorTree DT(*F);
175 Test(*F, &DT);
176 }
177
TEST(Local,MergeBasicBlockIntoOnlyPred)178 TEST(Local, MergeBasicBlockIntoOnlyPred) {
179 LLVMContext C;
180 std::unique_ptr<Module> M;
181 auto resetIR = [&]() {
182 M = parseIR(C,
183 R"(
184 define i32 @f(i8* %str) {
185 entry:
186 br label %bb2.i
187 bb2.i: ; preds = %bb4.i, %entry
188 br i1 false, label %bb4.i, label %base2flt.exit204
189 bb4.i: ; preds = %bb2.i
190 br i1 false, label %base2flt.exit204, label %bb2.i
191 bb10.i196.bb7.i197_crit_edge: ; No predecessors!
192 br label %bb7.i197
193 bb7.i197: ; preds = %bb10.i196.bb7.i197_crit_edge
194 %.reg2mem.0 = phi i32 [ %.reg2mem.0, %bb10.i196.bb7.i197_crit_edge ]
195 br i1 undef, label %base2flt.exit204, label %base2flt.exit204
196 base2flt.exit204: ; preds = %bb7.i197, %bb7.i197, %bb2.i, %bb4.i
197 ret i32 0
198 }
199 )");
200 };
201
202 auto resetIRReplaceEntry = [&]() {
203 M = parseIR(C,
204 R"(
205 define i32 @f() {
206 entry:
207 br label %bb2.i
208 bb2.i: ; preds = %entry
209 ret i32 0
210 }
211 )");
212 };
213
214 auto Test = [&](Function &F, DomTreeUpdater &DTU) {
215 for (Function::iterator I = F.begin(), E = F.end(); I != E;) {
216 BasicBlock *BB = &*I++;
217 BasicBlock *SinglePred = BB->getSinglePredecessor();
218 if (!SinglePred || SinglePred == BB || BB->hasAddressTaken())
219 continue;
220 BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
221 if (Term && !Term->isConditional())
222 MergeBasicBlockIntoOnlyPred(BB, &DTU);
223 }
224 if (DTU.hasDomTree()) {
225 EXPECT_TRUE(DTU.getDomTree().verify());
226 }
227 if (DTU.hasPostDomTree()) {
228 EXPECT_TRUE(DTU.getPostDomTree().verify());
229 }
230 };
231
232 // Test MergeBasicBlockIntoOnlyPred working under Eager UpdateStrategy with
233 // both DT and PDT.
234 resetIR();
235 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
236 PostDominatorTree PDT = PostDominatorTree(F);
237 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Eager);
238 Test(F, DTU);
239 });
240
241 // Test MergeBasicBlockIntoOnlyPred working under Eager UpdateStrategy with
242 // DT.
243 resetIR();
244 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
245 DomTreeUpdater DTU(*DT, DomTreeUpdater::UpdateStrategy::Eager);
246 Test(F, DTU);
247 });
248
249 // Test MergeBasicBlockIntoOnlyPred working under Eager UpdateStrategy with
250 // PDT.
251 resetIR();
252 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
253 PostDominatorTree PDT = PostDominatorTree(F);
254 DomTreeUpdater DTU(PDT, DomTreeUpdater::UpdateStrategy::Eager);
255 Test(F, DTU);
256 });
257
258 // Test MergeBasicBlockIntoOnlyPred working under Lazy UpdateStrategy with
259 // both DT and PDT.
260 resetIR();
261 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
262 PostDominatorTree PDT = PostDominatorTree(F);
263 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy);
264 Test(F, DTU);
265 });
266
267 // Test MergeBasicBlockIntoOnlyPred working under Lazy UpdateStrategy with
268 // PDT.
269 resetIR();
270 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
271 PostDominatorTree PDT = PostDominatorTree(F);
272 DomTreeUpdater DTU(PDT, DomTreeUpdater::UpdateStrategy::Lazy);
273 Test(F, DTU);
274 });
275
276 // Test MergeBasicBlockIntoOnlyPred working under Lazy UpdateStrategy with DT.
277 resetIR();
278 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
279 DomTreeUpdater DTU(*DT, DomTreeUpdater::UpdateStrategy::Lazy);
280 Test(F, DTU);
281 });
282
283 // Test MergeBasicBlockIntoOnlyPred working under Eager UpdateStrategy with
284 // both DT and PDT.
285 resetIRReplaceEntry();
286 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
287 PostDominatorTree PDT = PostDominatorTree(F);
288 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Eager);
289 Test(F, DTU);
290 });
291
292 // Test MergeBasicBlockIntoOnlyPred working under Eager UpdateStrategy with
293 // DT.
294 resetIRReplaceEntry();
295 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
296 DomTreeUpdater DTU(*DT, DomTreeUpdater::UpdateStrategy::Eager);
297 Test(F, DTU);
298 });
299
300 // Test MergeBasicBlockIntoOnlyPred working under Eager UpdateStrategy with
301 // PDT.
302 resetIRReplaceEntry();
303 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
304 PostDominatorTree PDT = PostDominatorTree(F);
305 DomTreeUpdater DTU(PDT, DomTreeUpdater::UpdateStrategy::Eager);
306 Test(F, DTU);
307 });
308
309 // Test MergeBasicBlockIntoOnlyPred working under Lazy UpdateStrategy with
310 // both DT and PDT.
311 resetIRReplaceEntry();
312 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
313 PostDominatorTree PDT = PostDominatorTree(F);
314 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy);
315 Test(F, DTU);
316 });
317
318 // Test MergeBasicBlockIntoOnlyPred working under Lazy UpdateStrategy with
319 // PDT.
320 resetIRReplaceEntry();
321 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
322 PostDominatorTree PDT = PostDominatorTree(F);
323 DomTreeUpdater DTU(PDT, DomTreeUpdater::UpdateStrategy::Lazy);
324 Test(F, DTU);
325 });
326
327 // Test MergeBasicBlockIntoOnlyPred working under Lazy UpdateStrategy with DT.
328 resetIRReplaceEntry();
329 runWithDomTree(*M, "f", [&](Function &F, DominatorTree *DT) {
330 DomTreeUpdater DTU(*DT, DomTreeUpdater::UpdateStrategy::Lazy);
331 Test(F, DTU);
332 });
333 }
334
TEST(Local,ConstantFoldTerminator)335 TEST(Local, ConstantFoldTerminator) {
336 LLVMContext C;
337
338 std::unique_ptr<Module> M = parseIR(C,
339 R"(
340 define void @br_same_dest() {
341 entry:
342 br i1 false, label %bb0, label %bb0
343 bb0:
344 ret void
345 }
346
347 define void @br_different_dest() {
348 entry:
349 br i1 true, label %bb0, label %bb1
350 bb0:
351 br label %exit
352 bb1:
353 br label %exit
354 exit:
355 ret void
356 }
357
358 define void @switch_2_different_dest() {
359 entry:
360 switch i32 0, label %default [ i32 0, label %bb0 ]
361 default:
362 ret void
363 bb0:
364 ret void
365 }
366 define void @switch_2_different_dest_default() {
367 entry:
368 switch i32 1, label %default [ i32 0, label %bb0 ]
369 default:
370 ret void
371 bb0:
372 ret void
373 }
374 define void @switch_3_different_dest() {
375 entry:
376 switch i32 0, label %default [ i32 0, label %bb0
377 i32 1, label %bb1 ]
378 default:
379 ret void
380 bb0:
381 ret void
382 bb1:
383 ret void
384 }
385
386 define void @switch_variable_2_default_dest(i32 %arg) {
387 entry:
388 switch i32 %arg, label %default [ i32 0, label %default ]
389 default:
390 ret void
391 }
392
393 define void @switch_constant_2_default_dest() {
394 entry:
395 switch i32 1, label %default [ i32 0, label %default ]
396 default:
397 ret void
398 }
399
400 define void @switch_constant_3_repeated_dest() {
401 entry:
402 switch i32 0, label %default [ i32 0, label %bb0
403 i32 1, label %bb0 ]
404 bb0:
405 ret void
406 default:
407 ret void
408 }
409
410 define void @indirectbr() {
411 entry:
412 indirectbr i8* blockaddress(@indirectbr, %bb0), [label %bb0, label %bb1]
413 bb0:
414 ret void
415 bb1:
416 ret void
417 }
418
419 define void @indirectbr_repeated() {
420 entry:
421 indirectbr i8* blockaddress(@indirectbr_repeated, %bb0), [label %bb0, label %bb0]
422 bb0:
423 ret void
424 }
425
426 define void @indirectbr_unreachable() {
427 entry:
428 indirectbr i8* blockaddress(@indirectbr_unreachable, %bb0), [label %bb1]
429 bb0:
430 ret void
431 bb1:
432 ret void
433 }
434 )");
435
436 auto CFAllTerminatorsEager = [&](Function &F, DominatorTree *DT) {
437 PostDominatorTree PDT = PostDominatorTree(F);
438 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Eager);
439 for (Function::iterator I = F.begin(), E = F.end(); I != E;) {
440 BasicBlock *BB = &*I++;
441 ConstantFoldTerminator(BB, true, nullptr, &DTU);
442 }
443
444 EXPECT_TRUE(DTU.getDomTree().verify());
445 EXPECT_TRUE(DTU.getPostDomTree().verify());
446 };
447
448 auto CFAllTerminatorsLazy = [&](Function &F, DominatorTree *DT) {
449 PostDominatorTree PDT = PostDominatorTree(F);
450 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy);
451 for (Function::iterator I = F.begin(), E = F.end(); I != E;) {
452 BasicBlock *BB = &*I++;
453 ConstantFoldTerminator(BB, true, nullptr, &DTU);
454 }
455
456 EXPECT_TRUE(DTU.getDomTree().verify());
457 EXPECT_TRUE(DTU.getPostDomTree().verify());
458 };
459
460 // Test ConstantFoldTerminator under Eager UpdateStrategy.
461 runWithDomTree(*M, "br_same_dest", CFAllTerminatorsEager);
462 runWithDomTree(*M, "br_different_dest", CFAllTerminatorsEager);
463 runWithDomTree(*M, "switch_2_different_dest", CFAllTerminatorsEager);
464 runWithDomTree(*M, "switch_2_different_dest_default", CFAllTerminatorsEager);
465 runWithDomTree(*M, "switch_3_different_dest", CFAllTerminatorsEager);
466 runWithDomTree(*M, "switch_variable_2_default_dest", CFAllTerminatorsEager);
467 runWithDomTree(*M, "switch_constant_2_default_dest", CFAllTerminatorsEager);
468 runWithDomTree(*M, "switch_constant_3_repeated_dest", CFAllTerminatorsEager);
469 runWithDomTree(*M, "indirectbr", CFAllTerminatorsEager);
470 runWithDomTree(*M, "indirectbr_repeated", CFAllTerminatorsEager);
471 runWithDomTree(*M, "indirectbr_unreachable", CFAllTerminatorsEager);
472
473 // Test ConstantFoldTerminator under Lazy UpdateStrategy.
474 runWithDomTree(*M, "br_same_dest", CFAllTerminatorsLazy);
475 runWithDomTree(*M, "br_different_dest", CFAllTerminatorsLazy);
476 runWithDomTree(*M, "switch_2_different_dest", CFAllTerminatorsLazy);
477 runWithDomTree(*M, "switch_2_different_dest_default", CFAllTerminatorsLazy);
478 runWithDomTree(*M, "switch_3_different_dest", CFAllTerminatorsLazy);
479 runWithDomTree(*M, "switch_variable_2_default_dest", CFAllTerminatorsLazy);
480 runWithDomTree(*M, "switch_constant_2_default_dest", CFAllTerminatorsLazy);
481 runWithDomTree(*M, "switch_constant_3_repeated_dest", CFAllTerminatorsLazy);
482 runWithDomTree(*M, "indirectbr", CFAllTerminatorsLazy);
483 runWithDomTree(*M, "indirectbr_repeated", CFAllTerminatorsLazy);
484 runWithDomTree(*M, "indirectbr_unreachable", CFAllTerminatorsLazy);
485 }
486
487 struct SalvageDebugInfoTest : ::testing::Test {
488 LLVMContext C;
489 std::unique_ptr<Module> M;
490 Function *F = nullptr;
491
SetUpSalvageDebugInfoTest492 void SetUp() {
493 M = parseIR(C,
494 R"(
495 define void @f() !dbg !8 {
496 entry:
497 %x = add i32 0, 1
498 %y = add i32 %x, 2
499 call void @llvm.dbg.value(metadata i32 %x, metadata !11, metadata !DIExpression()), !dbg !13
500 call void @llvm.dbg.value(metadata i32 %y, metadata !11, metadata !DIExpression()), !dbg !13
501 ret void, !dbg !14
502 }
503 declare void @llvm.dbg.value(metadata, metadata, metadata)
504 !llvm.dbg.cu = !{!0}
505 !llvm.module.flags = !{!3, !4}
506 !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
507 !1 = !DIFile(filename: "t2.c", directory: "foo")
508 !2 = !{}
509 !3 = !{i32 2, !"Dwarf Version", i32 4}
510 !4 = !{i32 2, !"Debug Info Version", i32 3}
511 !8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, unit: !0, retainedNodes: !2)
512 !9 = !DISubroutineType(types: !10)
513 !10 = !{null}
514 !11 = !DILocalVariable(name: "x", scope: !8, file: !1, line: 2, type: !12)
515 !12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
516 !13 = !DILocation(line: 2, column: 7, scope: !8)
517 !14 = !DILocation(line: 3, column: 1, scope: !8)
518 )");
519
520 auto *GV = M->getNamedValue("f");
521 ASSERT_TRUE(GV);
522 F = dyn_cast<Function>(GV);
523 ASSERT_TRUE(F);
524 }
525
doesDebugValueDescribeXSalvageDebugInfoTest526 bool doesDebugValueDescribeX(const DbgValueInst &DI) {
527 const auto &CI = *cast<ConstantInt>(DI.getValue());
528 if (CI.isZero())
529 return DI.getExpression()->getElements().equals(
530 {dwarf::DW_OP_plus_uconst, 1, dwarf::DW_OP_stack_value});
531 else if (CI.isOneValue())
532 return DI.getExpression()->getElements().empty();
533 return false;
534 }
535
doesDebugValueDescribeYSalvageDebugInfoTest536 bool doesDebugValueDescribeY(const DbgValueInst &DI) {
537 const auto &CI = *cast<ConstantInt>(DI.getValue());
538 if (CI.isZero())
539 return DI.getExpression()->getElements().equals(
540 {dwarf::DW_OP_plus_uconst, 1, dwarf::DW_OP_plus_uconst, 2,
541 dwarf::DW_OP_stack_value});
542 else if (CI.isOneValue())
543 return DI.getExpression()->getElements().equals(
544 {dwarf::DW_OP_plus_uconst, 2, dwarf::DW_OP_stack_value});
545 return false;
546 }
547
verifyDebugValuesAreSalvagedSalvageDebugInfoTest548 void verifyDebugValuesAreSalvaged() {
549 // Check that the debug values for %x and %y are preserved.
550 bool FoundX = false;
551 bool FoundY = false;
552 for (const Instruction &I : F->front()) {
553 auto DI = dyn_cast<DbgValueInst>(&I);
554 if (!DI) {
555 // The function should only contain debug values and a terminator.
556 ASSERT_TRUE(I.isTerminator());
557 continue;
558 }
559 EXPECT_EQ(DI->getVariable()->getName(), "x");
560 FoundX |= doesDebugValueDescribeX(*DI);
561 FoundY |= doesDebugValueDescribeY(*DI);
562 }
563 ASSERT_TRUE(FoundX);
564 ASSERT_TRUE(FoundY);
565 }
566 };
567
TEST_F(SalvageDebugInfoTest,RecursiveInstDeletion)568 TEST_F(SalvageDebugInfoTest, RecursiveInstDeletion) {
569 Instruction *Inst = &F->front().front();
570 Inst = Inst->getNextNode(); // Get %y = add ...
571 ASSERT_TRUE(Inst);
572 bool Deleted = RecursivelyDeleteTriviallyDeadInstructions(Inst);
573 ASSERT_TRUE(Deleted);
574 verifyDebugValuesAreSalvaged();
575 }
576
TEST_F(SalvageDebugInfoTest,RecursiveBlockSimplification)577 TEST_F(SalvageDebugInfoTest, RecursiveBlockSimplification) {
578 BasicBlock *BB = &F->front();
579 ASSERT_TRUE(BB);
580 bool Deleted = SimplifyInstructionsInBlock(BB);
581 ASSERT_TRUE(Deleted);
582 verifyDebugValuesAreSalvaged();
583 }
584
TEST(Local,ChangeToUnreachable)585 TEST(Local, ChangeToUnreachable) {
586 LLVMContext Ctx;
587
588 std::unique_ptr<Module> M = parseIR(Ctx,
589 R"(
590 define internal void @foo() !dbg !6 {
591 entry:
592 ret void, !dbg !8
593 }
594
595 !llvm.dbg.cu = !{!0}
596 !llvm.debugify = !{!3, !4}
597 !llvm.module.flags = !{!5}
598
599 !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
600 !1 = !DIFile(filename: "test.ll", directory: "/")
601 !2 = !{}
602 !3 = !{i32 1}
603 !4 = !{i32 0}
604 !5 = !{i32 2, !"Debug Info Version", i32 3}
605 !6 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !1, line: 1, type: !7, isLocal: true, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, retainedNodes: !2)
606 !7 = !DISubroutineType(types: !2)
607 !8 = !DILocation(line: 1, column: 1, scope: !6)
608 )");
609
610 bool BrokenDebugInfo = true;
611 verifyModule(*M, &errs(), &BrokenDebugInfo);
612 ASSERT_FALSE(BrokenDebugInfo);
613
614 Function &F = *cast<Function>(M->getNamedValue("foo"));
615
616 BasicBlock &BB = F.front();
617 Instruction &A = BB.front();
618 DebugLoc DLA = A.getDebugLoc();
619
620 ASSERT_TRUE(isa<ReturnInst>(&A));
621 // One instruction should be affected.
622 EXPECT_EQ(changeToUnreachable(&A, /*UseLLVMTrap*/false), 1U);
623
624 Instruction &B = BB.front();
625
626 // There should be an uncreachable instruction.
627 ASSERT_TRUE(isa<UnreachableInst>(&B));
628
629 DebugLoc DLB = B.getDebugLoc();
630 EXPECT_EQ(DLA, DLB);
631 }
632
TEST(Local,ReplaceAllDbgUsesWith)633 TEST(Local, ReplaceAllDbgUsesWith) {
634 using namespace llvm::dwarf;
635
636 LLVMContext Ctx;
637
638 // Note: The datalayout simulates Darwin/x86_64.
639 std::unique_ptr<Module> M = parseIR(Ctx,
640 R"(
641 target datalayout = "e-m:o-i63:64-f80:128-n8:16:32:64-S128"
642
643 declare i32 @escape(i32)
644
645 define void @f() !dbg !6 {
646 entry:
647 %a = add i32 0, 1, !dbg !15
648 call void @llvm.dbg.value(metadata i32 %a, metadata !9, metadata !DIExpression()), !dbg !15
649
650 %b = add i64 0, 1, !dbg !16
651 call void @llvm.dbg.value(metadata i64 %b, metadata !11, metadata !DIExpression()), !dbg !16
652 call void @llvm.dbg.value(metadata i64 %b, metadata !11, metadata !DIExpression(DW_OP_lit0, DW_OP_mul)), !dbg !16
653 call void @llvm.dbg.value(metadata i64 %b, metadata !11, metadata !DIExpression(DW_OP_lit0, DW_OP_mul, DW_OP_stack_value)), !dbg !16
654 call void @llvm.dbg.value(metadata i64 %b, metadata !11, metadata !DIExpression(DW_OP_LLVM_fragment, 0, 8)), !dbg !16
655 call void @llvm.dbg.value(metadata i64 %b, metadata !11, metadata !DIExpression(DW_OP_lit0, DW_OP_mul, DW_OP_LLVM_fragment, 0, 8)), !dbg !16
656 call void @llvm.dbg.value(metadata i64 %b, metadata !11, metadata !DIExpression(DW_OP_lit0, DW_OP_mul, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8)), !dbg !16
657
658 %c = inttoptr i64 0 to i64*, !dbg !17
659 call void @llvm.dbg.declare(metadata i64* %c, metadata !13, metadata !DIExpression()), !dbg !17
660
661 %d = inttoptr i64 0 to i32*, !dbg !18
662 call void @llvm.dbg.addr(metadata i32* %d, metadata !20, metadata !DIExpression()), !dbg !18
663
664 %e = add <2 x i16> zeroinitializer, zeroinitializer
665 call void @llvm.dbg.value(metadata <2 x i16> %e, metadata !14, metadata !DIExpression()), !dbg !18
666
667 %f = call i32 @escape(i32 0)
668 call void @llvm.dbg.value(metadata i32 %f, metadata !9, metadata !DIExpression()), !dbg !15
669
670 %barrier = call i32 @escape(i32 0)
671
672 %g = call i32 @escape(i32 %f)
673 call void @llvm.dbg.value(metadata i32 %g, metadata !9, metadata !DIExpression()), !dbg !15
674
675 ret void, !dbg !19
676 }
677
678 declare void @llvm.dbg.addr(metadata, metadata, metadata)
679 declare void @llvm.dbg.declare(metadata, metadata, metadata)
680 declare void @llvm.dbg.value(metadata, metadata, metadata)
681
682 !llvm.dbg.cu = !{!0}
683 !llvm.module.flags = !{!5}
684
685 !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
686 !1 = !DIFile(filename: "/Users/vsk/Desktop/foo.ll", directory: "/")
687 !2 = !{}
688 !5 = !{i32 2, !"Debug Info Version", i32 3}
689 !6 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, retainedNodes: !8)
690 !7 = !DISubroutineType(types: !2)
691 !8 = !{!9, !11, !13, !14}
692 !9 = !DILocalVariable(name: "1", scope: !6, file: !1, line: 1, type: !10)
693 !10 = !DIBasicType(name: "ty32", size: 32, encoding: DW_ATE_signed)
694 !11 = !DILocalVariable(name: "2", scope: !6, file: !1, line: 2, type: !12)
695 !12 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_signed)
696 !13 = !DILocalVariable(name: "3", scope: !6, file: !1, line: 3, type: !12)
697 !14 = !DILocalVariable(name: "4", scope: !6, file: !1, line: 4, type: !10)
698 !15 = !DILocation(line: 1, column: 1, scope: !6)
699 !16 = !DILocation(line: 2, column: 1, scope: !6)
700 !17 = !DILocation(line: 3, column: 1, scope: !6)
701 !18 = !DILocation(line: 4, column: 1, scope: !6)
702 !19 = !DILocation(line: 5, column: 1, scope: !6)
703 !20 = !DILocalVariable(name: "5", scope: !6, file: !1, line: 5, type: !10)
704 )");
705
706 bool BrokenDebugInfo = true;
707 verifyModule(*M, &errs(), &BrokenDebugInfo);
708 ASSERT_FALSE(BrokenDebugInfo);
709
710 Function &F = *cast<Function>(M->getNamedValue("f"));
711 DominatorTree DT{F};
712
713 BasicBlock &BB = F.front();
714 Instruction &A = BB.front();
715 Instruction &B = *A.getNextNonDebugInstruction();
716 Instruction &C = *B.getNextNonDebugInstruction();
717 Instruction &D = *C.getNextNonDebugInstruction();
718 Instruction &E = *D.getNextNonDebugInstruction();
719 Instruction &F_ = *E.getNextNonDebugInstruction();
720 Instruction &Barrier = *F_.getNextNonDebugInstruction();
721 Instruction &G = *Barrier.getNextNonDebugInstruction();
722
723 // Simulate i32 <-> i64* conversion. Expect no updates: the datalayout says
724 // pointers are 64 bits, so the conversion would be lossy.
725 EXPECT_FALSE(replaceAllDbgUsesWith(A, C, C, DT));
726 EXPECT_FALSE(replaceAllDbgUsesWith(C, A, A, DT));
727
728 // Simulate i32 <-> <2 x i16> conversion. This is unsupported.
729 EXPECT_FALSE(replaceAllDbgUsesWith(E, A, A, DT));
730 EXPECT_FALSE(replaceAllDbgUsesWith(A, E, E, DT));
731
732 // Simulate i32* <-> i64* conversion.
733 EXPECT_TRUE(replaceAllDbgUsesWith(D, C, C, DT));
734
735 SmallVector<DbgVariableIntrinsic *, 2> CDbgVals;
736 findDbgUsers(CDbgVals, &C);
737 EXPECT_EQ(2U, CDbgVals.size());
738 EXPECT_TRUE(any_of(CDbgVals, [](DbgVariableIntrinsic *DII) {
739 return isa<DbgAddrIntrinsic>(DII);
740 }));
741 EXPECT_TRUE(any_of(CDbgVals, [](DbgVariableIntrinsic *DII) {
742 return isa<DbgDeclareInst>(DII);
743 }));
744
745 EXPECT_TRUE(replaceAllDbgUsesWith(C, D, D, DT));
746
747 SmallVector<DbgVariableIntrinsic *, 2> DDbgVals;
748 findDbgUsers(DDbgVals, &D);
749 EXPECT_EQ(2U, DDbgVals.size());
750 EXPECT_TRUE(any_of(DDbgVals, [](DbgVariableIntrinsic *DII) {
751 return isa<DbgAddrIntrinsic>(DII);
752 }));
753 EXPECT_TRUE(any_of(DDbgVals, [](DbgVariableIntrinsic *DII) {
754 return isa<DbgDeclareInst>(DII);
755 }));
756
757 // Introduce a use-before-def. Check that the dbg.value for %a is salvaged.
758 EXPECT_TRUE(replaceAllDbgUsesWith(A, F_, F_, DT));
759
760 auto *ADbgVal = cast<DbgValueInst>(A.getNextNode());
761 EXPECT_EQ(ConstantInt::get(A.getType(), 0), ADbgVal->getVariableLocation());
762
763 // Introduce a use-before-def. Check that the dbg.values for %f become undef.
764 EXPECT_TRUE(replaceAllDbgUsesWith(F_, G, G, DT));
765
766 auto *FDbgVal = cast<DbgValueInst>(F_.getNextNode());
767 EXPECT_TRUE(isa<UndefValue>(FDbgVal->getVariableLocation()));
768
769 SmallVector<DbgValueInst *, 1> FDbgVals;
770 findDbgValues(FDbgVals, &F_);
771 EXPECT_EQ(0U, FDbgVals.size());
772
773 // Simulate i32 -> i64 conversion to test sign-extension. Here are some
774 // interesting cases to handle:
775 // 1) debug user has empty DIExpression
776 // 2) debug user has non-empty, non-stack-value'd DIExpression
777 // 3) debug user has non-empty, stack-value'd DIExpression
778 // 4-6) like (1-3), but with a fragment
779 EXPECT_TRUE(replaceAllDbgUsesWith(B, A, A, DT));
780
781 SmallVector<DbgValueInst *, 8> ADbgVals;
782 findDbgValues(ADbgVals, &A);
783 EXPECT_EQ(6U, ADbgVals.size());
784
785 // Check that %a has a dbg.value with a DIExpression matching \p Ops.
786 auto hasADbgVal = [&](ArrayRef<uint64_t> Ops) {
787 return any_of(ADbgVals, [&](DbgValueInst *DVI) {
788 assert(DVI->getVariable()->getName() == "2");
789 return DVI->getExpression()->getElements() == Ops;
790 });
791 };
792
793 // Case 1: The original expr is empty, so no deref is needed.
794 EXPECT_TRUE(hasADbgVal({DW_OP_LLVM_convert, 32, DW_ATE_signed,
795 DW_OP_LLVM_convert, 64, DW_ATE_signed,
796 DW_OP_stack_value}));
797
798 // Case 2: Perform an address calculation with the original expr, deref it,
799 // then sign-extend the result.
800 EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_deref,
801 DW_OP_LLVM_convert, 32, DW_ATE_signed,
802 DW_OP_LLVM_convert, 64, DW_ATE_signed,
803 DW_OP_stack_value}));
804
805 // Case 3: Insert the sign-extension logic before the DW_OP_stack_value.
806 EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_LLVM_convert, 32,
807 DW_ATE_signed, DW_OP_LLVM_convert, 64, DW_ATE_signed,
808 DW_OP_stack_value}));
809
810 // Cases 4-6: Just like cases 1-3, but preserve the fragment at the end.
811 EXPECT_TRUE(hasADbgVal({DW_OP_LLVM_convert, 32, DW_ATE_signed,
812 DW_OP_LLVM_convert, 64, DW_ATE_signed,
813 DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
814
815 EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_deref,
816 DW_OP_LLVM_convert, 32, DW_ATE_signed,
817 DW_OP_LLVM_convert, 64, DW_ATE_signed,
818 DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
819
820 EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_LLVM_convert, 32,
821 DW_ATE_signed, DW_OP_LLVM_convert, 64, DW_ATE_signed,
822 DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
823
824 verifyModule(*M, &errs(), &BrokenDebugInfo);
825 ASSERT_FALSE(BrokenDebugInfo);
826 }
827
TEST(Local,RemoveUnreachableBlocks)828 TEST(Local, RemoveUnreachableBlocks) {
829 LLVMContext C;
830
831 std::unique_ptr<Module> M = parseIR(C,
832 R"(
833 define void @br_simple() {
834 entry:
835 br label %bb0
836 bb0:
837 ret void
838 bb1:
839 ret void
840 }
841
842 define void @br_self_loop() {
843 entry:
844 br label %bb0
845 bb0:
846 br i1 true, label %bb1, label %bb0
847 bb1:
848 br i1 true, label %bb0, label %bb2
849 bb2:
850 br label %bb2
851 }
852
853 define void @br_constant() {
854 entry:
855 br label %bb0
856 bb0:
857 br i1 true, label %bb1, label %bb2
858 bb1:
859 br i1 true, label %bb0, label %bb2
860 bb2:
861 br label %bb2
862 }
863
864 define void @br_loop() {
865 entry:
866 br label %bb0
867 bb0:
868 br label %bb0
869 bb1:
870 br label %bb2
871 bb2:
872 br label %bb1
873 }
874
875 declare i32 @__gxx_personality_v0(...)
876
877 define void @invoke_terminator() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
878 entry:
879 br i1 undef, label %invoke.block, label %exit
880
881 invoke.block:
882 %cond = invoke zeroext i1 @invokable()
883 to label %continue.block unwind label %lpad.block
884
885 continue.block:
886 br i1 %cond, label %if.then, label %if.end
887
888 if.then:
889 unreachable
890
891 if.end:
892 unreachable
893
894 lpad.block:
895 %lp = landingpad { i8*, i32 }
896 catch i8* null
897 br label %exit
898
899 exit:
900 ret void
901 }
902
903 declare i1 @invokable()
904 )");
905
906 auto runEager = [&](Function &F, DominatorTree *DT) {
907 PostDominatorTree PDT = PostDominatorTree(F);
908 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Eager);
909 removeUnreachableBlocks(F, &DTU);
910 EXPECT_TRUE(DTU.getDomTree().verify());
911 EXPECT_TRUE(DTU.getPostDomTree().verify());
912 };
913
914 auto runLazy = [&](Function &F, DominatorTree *DT) {
915 PostDominatorTree PDT = PostDominatorTree(F);
916 DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy);
917 removeUnreachableBlocks(F, &DTU);
918 EXPECT_TRUE(DTU.getDomTree().verify());
919 EXPECT_TRUE(DTU.getPostDomTree().verify());
920 };
921
922 // Test removeUnreachableBlocks under Eager UpdateStrategy.
923 runWithDomTree(*M, "br_simple", runEager);
924 runWithDomTree(*M, "br_self_loop", runEager);
925 runWithDomTree(*M, "br_constant", runEager);
926 runWithDomTree(*M, "br_loop", runEager);
927 runWithDomTree(*M, "invoke_terminator", runEager);
928
929 // Test removeUnreachableBlocks under Lazy UpdateStrategy.
930 runWithDomTree(*M, "br_simple", runLazy);
931 runWithDomTree(*M, "br_self_loop", runLazy);
932 runWithDomTree(*M, "br_constant", runLazy);
933 runWithDomTree(*M, "br_loop", runLazy);
934 runWithDomTree(*M, "invoke_terminator", runLazy);
935
936 M = parseIR(C,
937 R"(
938 define void @f() {
939 entry:
940 ret void
941 bb0:
942 ret void
943 }
944 )");
945
946 auto checkRUBlocksRetVal = [&](Function &F, DominatorTree *DT) {
947 DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
948 EXPECT_TRUE(removeUnreachableBlocks(F, &DTU));
949 EXPECT_FALSE(removeUnreachableBlocks(F, &DTU));
950 EXPECT_TRUE(DTU.getDomTree().verify());
951 };
952
953 runWithDomTree(*M, "f", checkRUBlocksRetVal);
954 }
955
TEST(Local,SimplifyCFGWithNullAC)956 TEST(Local, SimplifyCFGWithNullAC) {
957 LLVMContext Ctx;
958
959 std::unique_ptr<Module> M = parseIR(Ctx, R"(
960 declare void @true_path()
961 declare void @false_path()
962 declare void @llvm.assume(i1 %cond);
963
964 define i32 @foo(i1, i32) {
965 entry:
966 %cmp = icmp sgt i32 %1, 0
967 br i1 %cmp, label %if.bb1, label %then.bb1
968 if.bb1:
969 call void @true_path()
970 br label %test.bb
971 then.bb1:
972 call void @false_path()
973 br label %test.bb
974 test.bb:
975 %phi = phi i1 [1, %if.bb1], [%0, %then.bb1]
976 call void @llvm.assume(i1 %0)
977 br i1 %phi, label %if.bb2, label %then.bb2
978 if.bb2:
979 ret i32 %1
980 then.bb2:
981 ret i32 0
982 }
983 )");
984
985 Function &F = *cast<Function>(M->getNamedValue("foo"));
986 TargetTransformInfo TTI(M->getDataLayout());
987
988 SimplifyCFGOptions Options{};
989 Options.setAssumptionCache(nullptr);
990
991 // Obtain BasicBlock of interest to this test, %test.bb.
992 BasicBlock *TestBB = nullptr;
993 for (BasicBlock &BB : F) {
994 if (BB.getName().equals("test.bb")) {
995 TestBB = &BB;
996 break;
997 }
998 }
999 ASSERT_TRUE(TestBB);
1000
1001 // %test.bb is expected to be simplified by FoldCondBranchOnPHI.
1002 EXPECT_TRUE(simplifyCFG(TestBB, TTI, Options));
1003 }
1004
TEST(Local,CanReplaceOperandWithVariable)1005 TEST(Local, CanReplaceOperandWithVariable) {
1006 LLVMContext Ctx;
1007 Module M("test_module", Ctx);
1008 IRBuilder<> B(Ctx);
1009
1010 FunctionType *FnType =
1011 FunctionType::get(Type::getVoidTy(Ctx), {}, false);
1012
1013 FunctionType *VarArgFnType =
1014 FunctionType::get(Type::getVoidTy(Ctx), {B.getInt32Ty()}, true);
1015
1016 Function *TestBody = Function::Create(FnType, GlobalValue::ExternalLinkage,
1017 0, "", &M);
1018
1019 BasicBlock *BB0 = BasicBlock::Create(Ctx, "", TestBody);
1020 B.SetInsertPoint(BB0);
1021
1022 FunctionCallee Intrin = M.getOrInsertFunction("llvm.foo", FnType);
1023 FunctionCallee Func = M.getOrInsertFunction("foo", FnType);
1024 FunctionCallee VarArgFunc
1025 = M.getOrInsertFunction("foo.vararg", VarArgFnType);
1026 FunctionCallee VarArgIntrin
1027 = M.getOrInsertFunction("llvm.foo.vararg", VarArgFnType);
1028
1029 auto *CallToIntrin = B.CreateCall(Intrin);
1030 auto *CallToFunc = B.CreateCall(Func);
1031
1032 // Test if it's valid to replace the callee operand.
1033 EXPECT_FALSE(canReplaceOperandWithVariable(CallToIntrin, 0));
1034 EXPECT_TRUE(canReplaceOperandWithVariable(CallToFunc, 0));
1035
1036 // That it's invalid to replace an argument in the variadic argument list for
1037 // an intrinsic, but OK for a normal function.
1038 auto *CallToVarArgFunc = B.CreateCall(
1039 VarArgFunc, {B.getInt32(0), B.getInt32(1), B.getInt32(2)});
1040 EXPECT_TRUE(canReplaceOperandWithVariable(CallToVarArgFunc, 0));
1041 EXPECT_TRUE(canReplaceOperandWithVariable(CallToVarArgFunc, 1));
1042 EXPECT_TRUE(canReplaceOperandWithVariable(CallToVarArgFunc, 2));
1043 EXPECT_TRUE(canReplaceOperandWithVariable(CallToVarArgFunc, 3));
1044
1045 auto *CallToVarArgIntrin = B.CreateCall(
1046 VarArgIntrin, {B.getInt32(0), B.getInt32(1), B.getInt32(2)});
1047 EXPECT_TRUE(canReplaceOperandWithVariable(CallToVarArgIntrin, 0));
1048 EXPECT_FALSE(canReplaceOperandWithVariable(CallToVarArgIntrin, 1));
1049 EXPECT_FALSE(canReplaceOperandWithVariable(CallToVarArgIntrin, 2));
1050 EXPECT_FALSE(canReplaceOperandWithVariable(CallToVarArgIntrin, 3));
1051
1052 // Test that it's invalid to replace gcroot operands, even though it can't use
1053 // immarg.
1054 Type *PtrPtr = B.getInt8Ty()->getPointerTo(0);
1055 Value *Alloca = B.CreateAlloca(PtrPtr, (unsigned)0);
1056 CallInst *GCRoot = B.CreateIntrinsic(Intrinsic::gcroot, {},
1057 {Alloca, Constant::getNullValue(PtrPtr)});
1058 EXPECT_TRUE(canReplaceOperandWithVariable(GCRoot, 0)); // Alloca
1059 EXPECT_FALSE(canReplaceOperandWithVariable(GCRoot, 1));
1060 EXPECT_FALSE(canReplaceOperandWithVariable(GCRoot, 2));
1061
1062 BB0->dropAllReferences();
1063 }
1064