1 //===- llvm/unittest/Analysis/LoopPassManagerTest.cpp - LPM 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 "llvm/Transforms/Scalar/LoopPassManager.h"
10 #include "llvm/Analysis/AliasAnalysis.h"
11 #include "llvm/Analysis/AssumptionCache.h"
12 #include "llvm/Analysis/ScalarEvolution.h"
13 #include "llvm/Analysis/TargetLibraryInfo.h"
14 #include "llvm/Analysis/TargetTransformInfo.h"
15 #include "llvm/AsmParser/Parser.h"
16 #include "llvm/IR/Dominators.h"
17 #include "llvm/IR/Function.h"
18 #include "llvm/IR/LLVMContext.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/IR/PassManager.h"
21 #include "llvm/Support/SourceMgr.h"
22 
23 #include "gmock/gmock.h"
24 #include "gtest/gtest.h"
25 
26 using namespace llvm;
27 
28 namespace {
29 
30 using testing::DoDefault;
31 using testing::Return;
32 using testing::Expectation;
33 using testing::Invoke;
34 using testing::InvokeWithoutArgs;
35 using testing::_;
36 
37 template <typename DerivedT, typename IRUnitT,
38           typename AnalysisManagerT = AnalysisManager<IRUnitT>,
39           typename... ExtraArgTs>
40 class MockAnalysisHandleBase {
41 public:
42   class Analysis : public AnalysisInfoMixin<Analysis> {
43     friend AnalysisInfoMixin<Analysis>;
44     friend MockAnalysisHandleBase;
45     static AnalysisKey Key;
46 
47     DerivedT *Handle;
48 
49     Analysis(DerivedT &Handle) : Handle(&Handle) {
50       static_assert(std::is_base_of<MockAnalysisHandleBase, DerivedT>::value,
51                     "Must pass the derived type to this template!");
52     }
53 
54   public:
55     class Result {
56       friend MockAnalysisHandleBase;
57 
58       DerivedT *Handle;
59 
60       Result(DerivedT &Handle) : Handle(&Handle) {}
61 
62     public:
63       // Forward invalidation events to the mock handle.
64       bool invalidate(IRUnitT &IR, const PreservedAnalyses &PA,
65                       typename AnalysisManagerT::Invalidator &Inv) {
66         return Handle->invalidate(IR, PA, Inv);
67       }
68     };
69 
70     Result run(IRUnitT &IR, AnalysisManagerT &AM, ExtraArgTs... ExtraArgs) {
71       return Handle->run(IR, AM, ExtraArgs...);
72     }
73   };
74 
75   Analysis getAnalysis() { return Analysis(static_cast<DerivedT &>(*this)); }
76   typename Analysis::Result getResult() {
77     return typename Analysis::Result(static_cast<DerivedT &>(*this));
78   }
79 
80 protected:
81   // FIXME: MSVC seems unable to handle a lambda argument to Invoke from within
82   // the template, so we use a boring static function.
83   static bool invalidateCallback(IRUnitT &IR, const PreservedAnalyses &PA,
84                                  typename AnalysisManagerT::Invalidator &Inv) {
85     auto PAC = PA.template getChecker<Analysis>();
86     return !PAC.preserved() &&
87            !PAC.template preservedSet<AllAnalysesOn<IRUnitT>>();
88   }
89 
90   /// Derived classes should call this in their constructor to set up default
91   /// mock actions. (We can't do this in our constructor because this has to
92   /// run after the DerivedT is constructed.)
93   void setDefaults() {
94     ON_CALL(static_cast<DerivedT &>(*this),
95             run(_, _, testing::Matcher<ExtraArgTs>(_)...))
96         .WillByDefault(Return(this->getResult()));
97     ON_CALL(static_cast<DerivedT &>(*this), invalidate(_, _, _))
98         .WillByDefault(Invoke(&invalidateCallback));
99   }
100 };
101 
102 template <typename DerivedT, typename IRUnitT, typename AnalysisManagerT,
103           typename... ExtraArgTs>
104 AnalysisKey MockAnalysisHandleBase<DerivedT, IRUnitT, AnalysisManagerT,
105                                    ExtraArgTs...>::Analysis::Key;
106 
107 /// Mock handle for loop analyses.
108 ///
109 /// This is provided as a template accepting an (optional) integer. Because
110 /// analyses are identified and queried by type, this allows constructing
111 /// multiple handles with distinctly typed nested 'Analysis' types that can be
112 /// registered and queried. If you want to register multiple loop analysis
113 /// passes, you'll need to instantiate this type with different values for I.
114 /// For example:
115 ///
116 ///   MockLoopAnalysisHandleTemplate<0> h0;
117 ///   MockLoopAnalysisHandleTemplate<1> h1;
118 ///   typedef decltype(h0)::Analysis Analysis0;
119 ///   typedef decltype(h1)::Analysis Analysis1;
120 template <size_t I = static_cast<size_t>(-1)>
121 struct MockLoopAnalysisHandleTemplate
122     : MockAnalysisHandleBase<MockLoopAnalysisHandleTemplate<I>, Loop,
123                              LoopAnalysisManager,
124                              LoopStandardAnalysisResults &> {
125   typedef typename MockLoopAnalysisHandleTemplate::Analysis Analysis;
126 
127   MOCK_METHOD3_T(run, typename Analysis::Result(Loop &, LoopAnalysisManager &,
128                                                 LoopStandardAnalysisResults &));
129 
130   MOCK_METHOD3_T(invalidate, bool(Loop &, const PreservedAnalyses &,
131                                   LoopAnalysisManager::Invalidator &));
132 
133   MockLoopAnalysisHandleTemplate() { this->setDefaults(); }
134 };
135 
136 typedef MockLoopAnalysisHandleTemplate<> MockLoopAnalysisHandle;
137 
138 struct MockFunctionAnalysisHandle
139     : MockAnalysisHandleBase<MockFunctionAnalysisHandle, Function> {
140   MOCK_METHOD2(run, Analysis::Result(Function &, FunctionAnalysisManager &));
141 
142   MOCK_METHOD3(invalidate, bool(Function &, const PreservedAnalyses &,
143                                 FunctionAnalysisManager::Invalidator &));
144 
145   MockFunctionAnalysisHandle() { setDefaults(); }
146 };
147 
148 template <typename DerivedT, typename IRUnitT,
149           typename AnalysisManagerT = AnalysisManager<IRUnitT>,
150           typename... ExtraArgTs>
151 class MockPassHandleBase {
152 public:
153   class Pass : public PassInfoMixin<Pass> {
154     friend MockPassHandleBase;
155 
156     DerivedT *Handle;
157 
158     Pass(DerivedT &Handle) : Handle(&Handle) {
159       static_assert(std::is_base_of<MockPassHandleBase, DerivedT>::value,
160                     "Must pass the derived type to this template!");
161     }
162 
163   public:
164     PreservedAnalyses run(IRUnitT &IR, AnalysisManagerT &AM,
165                           ExtraArgTs... ExtraArgs) {
166       return Handle->run(IR, AM, ExtraArgs...);
167     }
168   };
169 
170   Pass getPass() { return Pass(static_cast<DerivedT &>(*this)); }
171 
172 protected:
173   /// Derived classes should call this in their constructor to set up default
174   /// mock actions. (We can't do this in our constructor because this has to
175   /// run after the DerivedT is constructed.)
176   void setDefaults() {
177     ON_CALL(static_cast<DerivedT &>(*this),
178             run(_, _, testing::Matcher<ExtraArgTs>(_)...))
179         .WillByDefault(Return(PreservedAnalyses::all()));
180   }
181 };
182 
183 struct MockLoopPassHandle
184     : MockPassHandleBase<MockLoopPassHandle, Loop, LoopAnalysisManager,
185                          LoopStandardAnalysisResults &, LPMUpdater &> {
186   MOCK_METHOD4(run,
187                PreservedAnalyses(Loop &, LoopAnalysisManager &,
188                                  LoopStandardAnalysisResults &, LPMUpdater &));
189   MockLoopPassHandle() { setDefaults(); }
190 };
191 
192 struct MockFunctionPassHandle
193     : MockPassHandleBase<MockFunctionPassHandle, Function> {
194   MOCK_METHOD2(run, PreservedAnalyses(Function &, FunctionAnalysisManager &));
195 
196   MockFunctionPassHandle() { setDefaults(); }
197 };
198 
199 struct MockModulePassHandle : MockPassHandleBase<MockModulePassHandle, Module> {
200   MOCK_METHOD2(run, PreservedAnalyses(Module &, ModuleAnalysisManager &));
201 
202   MockModulePassHandle() { setDefaults(); }
203 };
204 
205 /// Define a custom matcher for objects which support a 'getName' method
206 /// returning a StringRef.
207 ///
208 /// LLVM often has IR objects or analysis objects which expose a StringRef name
209 /// and in tests it is convenient to match these by name for readability. This
210 /// matcher supports any type exposing a getName() method of this form.
211 ///
212 /// It should be used as:
213 ///
214 ///   HasName("my_function")
215 ///
216 /// No namespace or other qualification is required.
217 MATCHER_P(HasName, Name, "") {
218   // The matcher's name and argument are printed in the case of failure, but we
219   // also want to print out the name of the argument. This uses an implicitly
220   // avaiable std::ostream, so we have to construct a std::string.
221   *result_listener << "has name '" << arg.getName().str() << "'";
222   return Name == arg.getName();
223 }
224 
225 std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
226   SMDiagnostic Err;
227   return parseAssemblyString(IR, Err, C);
228 }
229 
230 class LoopPassManagerTest : public ::testing::Test {
231 protected:
232   LLVMContext Context;
233   std::unique_ptr<Module> M;
234 
235   LoopAnalysisManager LAM;
236   FunctionAnalysisManager FAM;
237   ModuleAnalysisManager MAM;
238 
239   MockLoopAnalysisHandle MLAHandle;
240   MockLoopPassHandle MLPHandle;
241   MockFunctionPassHandle MFPHandle;
242   MockModulePassHandle MMPHandle;
243 
244   static PreservedAnalyses
245   getLoopAnalysisResult(Loop &L, LoopAnalysisManager &AM,
246                         LoopStandardAnalysisResults &AR, LPMUpdater &) {
247     (void)AM.getResult<MockLoopAnalysisHandle::Analysis>(L, AR);
248     return PreservedAnalyses::all();
249   };
250 
251 public:
252   LoopPassManagerTest()
253       : M(parseIR(Context,
254                   "define void @f(i1* %ptr) {\n"
255                   "entry:\n"
256                   "  br label %loop.0\n"
257                   "loop.0:\n"
258                   "  %cond.0 = load volatile i1, i1* %ptr\n"
259                   "  br i1 %cond.0, label %loop.0.0.ph, label %end\n"
260                   "loop.0.0.ph:\n"
261                   "  br label %loop.0.0\n"
262                   "loop.0.0:\n"
263                   "  %cond.0.0 = load volatile i1, i1* %ptr\n"
264                   "  br i1 %cond.0.0, label %loop.0.0, label %loop.0.1.ph\n"
265                   "loop.0.1.ph:\n"
266                   "  br label %loop.0.1\n"
267                   "loop.0.1:\n"
268                   "  %cond.0.1 = load volatile i1, i1* %ptr\n"
269                   "  br i1 %cond.0.1, label %loop.0.1, label %loop.0.latch\n"
270                   "loop.0.latch:\n"
271                   "  br label %loop.0\n"
272                   "end:\n"
273                   "  ret void\n"
274                   "}\n"
275                   "\n"
276                   "define void @g(i1* %ptr) {\n"
277                   "entry:\n"
278                   "  br label %loop.g.0\n"
279                   "loop.g.0:\n"
280                   "  %cond.0 = load volatile i1, i1* %ptr\n"
281                   "  br i1 %cond.0, label %loop.g.0, label %end\n"
282                   "end:\n"
283                   "  ret void\n"
284                   "}\n")),
285         LAM(true), FAM(true), MAM(true) {
286     // Register our mock analysis.
287     LAM.registerPass([&] { return MLAHandle.getAnalysis(); });
288 
289     // We need DominatorTreeAnalysis for LoopAnalysis.
290     FAM.registerPass([&] { return DominatorTreeAnalysis(); });
291     FAM.registerPass([&] { return LoopAnalysis(); });
292     // We also allow loop passes to assume a set of other analyses and so need
293     // those.
294     FAM.registerPass([&] { return AAManager(); });
295     FAM.registerPass([&] { return AssumptionAnalysis(); });
296     if (EnableMSSALoopDependency)
297       FAM.registerPass([&] { return MemorySSAAnalysis(); });
298     FAM.registerPass([&] { return ScalarEvolutionAnalysis(); });
299     FAM.registerPass([&] { return TargetLibraryAnalysis(); });
300     FAM.registerPass([&] { return TargetIRAnalysis(); });
301 
302     // Register required pass instrumentation analysis.
303     LAM.registerPass([&] { return PassInstrumentationAnalysis(); });
304     FAM.registerPass([&] { return PassInstrumentationAnalysis(); });
305     MAM.registerPass([&] { return PassInstrumentationAnalysis(); });
306 
307     // Cross-register proxies.
308     LAM.registerPass([&] { return FunctionAnalysisManagerLoopProxy(FAM); });
309     FAM.registerPass([&] { return LoopAnalysisManagerFunctionProxy(LAM); });
310     FAM.registerPass([&] { return ModuleAnalysisManagerFunctionProxy(MAM); });
311     MAM.registerPass([&] { return FunctionAnalysisManagerModuleProxy(FAM); });
312   }
313 };
314 
315 TEST_F(LoopPassManagerTest, Basic) {
316   ModulePassManager MPM(true);
317   ::testing::InSequence MakeExpectationsSequenced;
318 
319   // First we just visit all the loops in all the functions and get their
320   // analysis results. This will run the analysis a total of four times,
321   // once for each loop.
322   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
323       .WillOnce(Invoke(getLoopAnalysisResult));
324   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
325   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
326       .WillOnce(Invoke(getLoopAnalysisResult));
327   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
328   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
329       .WillOnce(Invoke(getLoopAnalysisResult));
330   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
331   EXPECT_CALL(MLPHandle, run(HasName("loop.g.0"), _, _, _))
332       .WillOnce(Invoke(getLoopAnalysisResult));
333   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
334   // Wire the loop pass through pass managers into the module pipeline.
335   {
336     LoopPassManager LPM(true);
337     LPM.addPass(MLPHandle.getPass());
338     FunctionPassManager FPM(true);
339     FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM)));
340     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
341   }
342 
343   // Next we run two passes over the loops. The first one invalidates the
344   // analyses for one loop, the second ones try to get the analysis results.
345   // This should force only one analysis to re-run within the loop PM, but will
346   // also invalidate everything after the loop pass manager finishes.
347   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
348       .WillOnce(DoDefault())
349       .WillOnce(Invoke(getLoopAnalysisResult));
350   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
351       .WillOnce(InvokeWithoutArgs([] { return PreservedAnalyses::none(); }))
352       .WillOnce(Invoke(getLoopAnalysisResult));
353   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
354   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
355       .WillOnce(DoDefault())
356       .WillOnce(Invoke(getLoopAnalysisResult));
357   EXPECT_CALL(MLPHandle, run(HasName("loop.g.0"), _, _, _))
358       .WillOnce(DoDefault())
359       .WillOnce(Invoke(getLoopAnalysisResult));
360   // Wire two loop pass runs into the module pipeline.
361   {
362     LoopPassManager LPM(true);
363     LPM.addPass(MLPHandle.getPass());
364     LPM.addPass(MLPHandle.getPass());
365     FunctionPassManager FPM(true);
366     FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM)));
367     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
368   }
369 
370   // And now run the pipeline across the module.
371   MPM.run(*M, MAM);
372 }
373 
374 TEST_F(LoopPassManagerTest, FunctionPassInvalidationOfLoopAnalyses) {
375   ModulePassManager MPM(true);
376   FunctionPassManager FPM(true);
377   // We process each function completely in sequence.
378   ::testing::Sequence FSequence, GSequence;
379 
380   // First, force the analysis result to be computed for each loop.
381   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _))
382       .InSequence(FSequence)
383       .WillOnce(DoDefault());
384   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _))
385       .InSequence(FSequence)
386       .WillOnce(DoDefault());
387   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _))
388       .InSequence(FSequence)
389       .WillOnce(DoDefault());
390   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _))
391       .InSequence(GSequence)
392       .WillOnce(DoDefault());
393   FPM.addPass(createFunctionToLoopPassAdaptor(
394       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
395 
396   // No need to re-run if we require again from a fresh loop pass manager.
397   FPM.addPass(createFunctionToLoopPassAdaptor(
398       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
399   // For 'f', preserve most things but not the specific loop analyses.
400   auto PA = getLoopPassPreservedAnalyses();
401   if (EnableMSSALoopDependency)
402     PA.preserve<MemorySSAAnalysis>();
403   EXPECT_CALL(MFPHandle, run(HasName("f"), _))
404       .InSequence(FSequence)
405       .WillOnce(Return(PA));
406   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0.0"), _, _))
407       .InSequence(FSequence)
408       .WillOnce(DoDefault());
409   // On one loop, skip the invalidation (as though we did an internal update).
410   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0.1"), _, _))
411       .InSequence(FSequence)
412       .WillOnce(Return(false));
413   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0"), _, _))
414       .InSequence(FSequence)
415       .WillOnce(DoDefault());
416   // Now two loops still have to be recomputed.
417   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _))
418       .InSequence(FSequence)
419       .WillOnce(DoDefault());
420   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _))
421       .InSequence(FSequence)
422       .WillOnce(DoDefault());
423   // Preserve things in the second function to ensure invalidation remains
424   // isolated to one function.
425   EXPECT_CALL(MFPHandle, run(HasName("g"), _))
426       .InSequence(GSequence)
427       .WillOnce(DoDefault());
428   FPM.addPass(MFPHandle.getPass());
429   FPM.addPass(createFunctionToLoopPassAdaptor(
430       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
431 
432   EXPECT_CALL(MFPHandle, run(HasName("f"), _))
433       .InSequence(FSequence)
434       .WillOnce(DoDefault());
435   // For 'g', fail to preserve anything, causing the loops themselves to be
436   // cleared. We don't get an invalidation event here as the loop is gone, but
437   // we should still have to recompute the analysis.
438   EXPECT_CALL(MFPHandle, run(HasName("g"), _))
439       .InSequence(GSequence)
440       .WillOnce(Return(PreservedAnalyses::none()));
441   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _))
442       .InSequence(GSequence)
443       .WillOnce(DoDefault());
444   FPM.addPass(MFPHandle.getPass());
445   FPM.addPass(createFunctionToLoopPassAdaptor(
446       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
447 
448   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
449 
450   // Verify with a separate function pass run that we didn't mess up 'f's
451   // cache. No analysis runs should be necessary here.
452   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
453       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
454 
455   MPM.run(*M, MAM);
456 }
457 
458 TEST_F(LoopPassManagerTest, ModulePassInvalidationOfLoopAnalyses) {
459   ModulePassManager MPM(true);
460   ::testing::InSequence MakeExpectationsSequenced;
461 
462   // First, force the analysis result to be computed for each loop.
463   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
464   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
465   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
466   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
467   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
468       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
469 
470   // Walking all the way out and all the way back in doesn't re-run the
471   // analysis.
472   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
473       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
474 
475   // But a module pass that doesn't preserve the actual mock loop analysis
476   // invalidates all the way down and forces recomputing.
477   EXPECT_CALL(MMPHandle, run(_, _)).WillOnce(InvokeWithoutArgs([] {
478     auto PA = getLoopPassPreservedAnalyses();
479     PA.preserve<FunctionAnalysisManagerModuleProxy>();
480     if (EnableMSSALoopDependency)
481       PA.preserve<MemorySSAAnalysis>();
482     return PA;
483   }));
484   // All the loop analyses from both functions get invalidated before we
485   // recompute anything.
486   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0.0"), _, _));
487   // On one loop, again skip the invalidation (as though we did an internal
488   // update).
489   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0.1"), _, _))
490       .WillOnce(Return(false));
491   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0"), _, _));
492   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.g.0"), _, _));
493   // Now all but one of the loops gets re-analyzed.
494   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
495   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
496   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
497   MPM.addPass(MMPHandle.getPass());
498   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
499       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
500 
501   // Verify that the cached values persist.
502   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
503       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
504 
505   // Now we fail to preserve the loop analysis and observe that the loop
506   // analyses are cleared (so no invalidation event) as the loops themselves
507   // are no longer valid.
508   EXPECT_CALL(MMPHandle, run(_, _)).WillOnce(InvokeWithoutArgs([] {
509     auto PA = PreservedAnalyses::none();
510     PA.preserve<FunctionAnalysisManagerModuleProxy>();
511     return PA;
512   }));
513   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
514   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
515   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
516   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
517   MPM.addPass(MMPHandle.getPass());
518   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
519       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
520 
521   // Verify that the cached values persist.
522   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
523       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
524 
525   // Next, check that even if we preserve everything within the function itelf,
526   // if the function's module pass proxy isn't preserved and the potential set
527   // of functions changes, the clear reaches the loop analyses as well. This
528   // will again trigger re-runs but not invalidation events.
529   EXPECT_CALL(MMPHandle, run(_, _)).WillOnce(InvokeWithoutArgs([] {
530     auto PA = PreservedAnalyses::none();
531     PA.preserveSet<AllAnalysesOn<Function>>();
532     PA.preserveSet<AllAnalysesOn<Loop>>();
533     return PA;
534   }));
535   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
536   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
537   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
538   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
539   MPM.addPass(MMPHandle.getPass());
540   MPM.addPass(createModuleToFunctionPassAdaptor(createFunctionToLoopPassAdaptor(
541       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>())));
542 
543   MPM.run(*M, MAM);
544 }
545 
546 // Test that if any of the bundled analyses provided in the LPM's signature
547 // become invalid, the analysis proxy itself becomes invalid and we clear all
548 // loop analysis results.
549 TEST_F(LoopPassManagerTest, InvalidationOfBundledAnalyses) {
550   ModulePassManager MPM(true);
551   FunctionPassManager FPM(true);
552   ::testing::InSequence MakeExpectationsSequenced;
553 
554   // First, force the analysis result to be computed for each loop.
555   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
556   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
557   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
558   FPM.addPass(createFunctionToLoopPassAdaptor(
559       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
560 
561   // No need to re-run if we require again from a fresh loop pass manager.
562   FPM.addPass(createFunctionToLoopPassAdaptor(
563       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
564 
565   // Preserving everything but the loop analyses themselves results in
566   // invalidation and running.
567   EXPECT_CALL(MFPHandle, run(HasName("f"), _))
568       .WillOnce(Return(getLoopPassPreservedAnalyses()));
569   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
570   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
571   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
572   FPM.addPass(MFPHandle.getPass());
573   FPM.addPass(createFunctionToLoopPassAdaptor(
574       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
575 
576   // The rest don't invalidate analyses, they only trigger re-runs because we
577   // clear the cache completely.
578   EXPECT_CALL(MFPHandle, run(HasName("f"), _)).WillOnce(InvokeWithoutArgs([] {
579     auto PA = PreservedAnalyses::none();
580     // Not preserving `AAManager`.
581     PA.preserve<DominatorTreeAnalysis>();
582     PA.preserve<LoopAnalysis>();
583     PA.preserve<LoopAnalysisManagerFunctionProxy>();
584     PA.preserve<ScalarEvolutionAnalysis>();
585     return PA;
586   }));
587   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
588   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
589   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
590   FPM.addPass(MFPHandle.getPass());
591   FPM.addPass(createFunctionToLoopPassAdaptor(
592       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
593 
594   EXPECT_CALL(MFPHandle, run(HasName("f"), _)).WillOnce(InvokeWithoutArgs([] {
595     auto PA = PreservedAnalyses::none();
596     PA.preserve<AAManager>();
597     // Not preserving `DominatorTreeAnalysis`.
598     PA.preserve<LoopAnalysis>();
599     PA.preserve<LoopAnalysisManagerFunctionProxy>();
600     PA.preserve<ScalarEvolutionAnalysis>();
601     return PA;
602   }));
603   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
604   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
605   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
606   FPM.addPass(MFPHandle.getPass());
607   FPM.addPass(createFunctionToLoopPassAdaptor(
608       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
609 
610   EXPECT_CALL(MFPHandle, run(HasName("f"), _)).WillOnce(InvokeWithoutArgs([] {
611     auto PA = PreservedAnalyses::none();
612     PA.preserve<AAManager>();
613     PA.preserve<DominatorTreeAnalysis>();
614     // Not preserving the `LoopAnalysis`.
615     PA.preserve<LoopAnalysisManagerFunctionProxy>();
616     PA.preserve<ScalarEvolutionAnalysis>();
617     return PA;
618   }));
619   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
620   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
621   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
622   FPM.addPass(MFPHandle.getPass());
623   FPM.addPass(createFunctionToLoopPassAdaptor(
624       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
625 
626   EXPECT_CALL(MFPHandle, run(HasName("f"), _)).WillOnce(InvokeWithoutArgs([] {
627     auto PA = PreservedAnalyses::none();
628     PA.preserve<AAManager>();
629     PA.preserve<DominatorTreeAnalysis>();
630     PA.preserve<LoopAnalysis>();
631     // Not preserving the `LoopAnalysisManagerFunctionProxy`.
632     PA.preserve<ScalarEvolutionAnalysis>();
633     return PA;
634   }));
635   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
636   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
637   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
638   FPM.addPass(MFPHandle.getPass());
639   FPM.addPass(createFunctionToLoopPassAdaptor(
640       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
641 
642   EXPECT_CALL(MFPHandle, run(HasName("f"), _)).WillOnce(InvokeWithoutArgs([] {
643     auto PA = PreservedAnalyses::none();
644     PA.preserve<AAManager>();
645     PA.preserve<DominatorTreeAnalysis>();
646     PA.preserve<LoopAnalysis>();
647     PA.preserve<LoopAnalysisManagerFunctionProxy>();
648     // Not preserving `ScalarEvolutionAnalysis`.
649     return PA;
650   }));
651   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
652   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
653   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
654   FPM.addPass(MFPHandle.getPass());
655   FPM.addPass(createFunctionToLoopPassAdaptor(
656       RequireAnalysisLoopPass<MockLoopAnalysisHandle::Analysis>()));
657 
658   // After all the churn on 'f', we'll compute the loop analysis results for
659   // 'g' once with a requires pass and then run our mock pass over g a bunch
660   // but just get cached results each time.
661   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
662   EXPECT_CALL(MFPHandle, run(HasName("g"), _)).Times(6);
663 
664   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
665   MPM.run(*M, MAM);
666 }
667 
668 TEST_F(LoopPassManagerTest, IndirectInvalidation) {
669   // We need two distinct analysis types and handles.
670   enum { A, B };
671   MockLoopAnalysisHandleTemplate<A> MLAHandleA;
672   MockLoopAnalysisHandleTemplate<B> MLAHandleB;
673   LAM.registerPass([&] { return MLAHandleA.getAnalysis(); });
674   LAM.registerPass([&] { return MLAHandleB.getAnalysis(); });
675   typedef decltype(MLAHandleA)::Analysis AnalysisA;
676   typedef decltype(MLAHandleB)::Analysis AnalysisB;
677 
678   // Set up AnalysisA to depend on our AnalysisB. For testing purposes we just
679   // need to get the AnalysisB results in AnalysisA's run method and check if
680   // AnalysisB gets invalidated in AnalysisA's invalidate method.
681   ON_CALL(MLAHandleA, run(_, _, _))
682       .WillByDefault(Invoke([&](Loop &L, LoopAnalysisManager &AM,
683                                 LoopStandardAnalysisResults &AR) {
684         (void)AM.getResult<AnalysisB>(L, AR);
685         return MLAHandleA.getResult();
686       }));
687   ON_CALL(MLAHandleA, invalidate(_, _, _))
688       .WillByDefault(Invoke([](Loop &L, const PreservedAnalyses &PA,
689                                LoopAnalysisManager::Invalidator &Inv) {
690         auto PAC = PA.getChecker<AnalysisA>();
691         return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Loop>>()) ||
692                Inv.invalidate<AnalysisB>(L, PA);
693       }));
694 
695   ::testing::InSequence MakeExpectationsSequenced;
696 
697   // Compute the analyses across all of 'f' first.
698   EXPECT_CALL(MLAHandleA, run(HasName("loop.0.0"), _, _));
699   EXPECT_CALL(MLAHandleB, run(HasName("loop.0.0"), _, _));
700   EXPECT_CALL(MLAHandleA, run(HasName("loop.0.1"), _, _));
701   EXPECT_CALL(MLAHandleB, run(HasName("loop.0.1"), _, _));
702   EXPECT_CALL(MLAHandleA, run(HasName("loop.0"), _, _));
703   EXPECT_CALL(MLAHandleB, run(HasName("loop.0"), _, _));
704 
705   // Now we invalidate AnalysisB (but not AnalysisA) for one of the loops and
706   // preserve everything for the rest. This in turn triggers that one loop to
707   // recompute both AnalysisB *and* AnalysisA if indirect invalidation is
708   // working.
709   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
710       .WillOnce(InvokeWithoutArgs([] {
711         auto PA = getLoopPassPreservedAnalyses();
712         // Specifically preserve AnalysisA so that it would survive if it
713         // didn't depend on AnalysisB.
714         PA.preserve<AnalysisA>();
715         return PA;
716       }));
717   // It happens that AnalysisB is invalidated first. That shouldn't matter
718   // though, and we should still call AnalysisA's invalidation.
719   EXPECT_CALL(MLAHandleB, invalidate(HasName("loop.0.0"), _, _));
720   EXPECT_CALL(MLAHandleA, invalidate(HasName("loop.0.0"), _, _));
721   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
722       .WillOnce(Invoke([](Loop &L, LoopAnalysisManager &AM,
723                           LoopStandardAnalysisResults &AR, LPMUpdater &) {
724         (void)AM.getResult<AnalysisA>(L, AR);
725         return PreservedAnalyses::all();
726       }));
727   EXPECT_CALL(MLAHandleA, run(HasName("loop.0.0"), _, _));
728   EXPECT_CALL(MLAHandleB, run(HasName("loop.0.0"), _, _));
729   // The rest of the loops should run and get cached results.
730   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
731       .Times(2)
732       .WillRepeatedly(Invoke([](Loop &L, LoopAnalysisManager &AM,
733                                 LoopStandardAnalysisResults &AR, LPMUpdater &) {
734         (void)AM.getResult<AnalysisA>(L, AR);
735         return PreservedAnalyses::all();
736       }));
737   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
738       .Times(2)
739       .WillRepeatedly(Invoke([](Loop &L, LoopAnalysisManager &AM,
740                                 LoopStandardAnalysisResults &AR, LPMUpdater &) {
741         (void)AM.getResult<AnalysisA>(L, AR);
742         return PreservedAnalyses::all();
743       }));
744 
745   // The run over 'g' should be boring, with us just computing the analyses once
746   // up front and then running loop passes and getting cached results.
747   EXPECT_CALL(MLAHandleA, run(HasName("loop.g.0"), _, _));
748   EXPECT_CALL(MLAHandleB, run(HasName("loop.g.0"), _, _));
749   EXPECT_CALL(MLPHandle, run(HasName("loop.g.0"), _, _, _))
750       .Times(2)
751       .WillRepeatedly(Invoke([](Loop &L, LoopAnalysisManager &AM,
752                                 LoopStandardAnalysisResults &AR, LPMUpdater &) {
753         (void)AM.getResult<AnalysisA>(L, AR);
754         return PreservedAnalyses::all();
755       }));
756 
757   // Build the pipeline and run it.
758   ModulePassManager MPM(true);
759   FunctionPassManager FPM(true);
760   FPM.addPass(
761       createFunctionToLoopPassAdaptor(RequireAnalysisLoopPass<AnalysisA>()));
762   LoopPassManager LPM(true);
763   LPM.addPass(MLPHandle.getPass());
764   LPM.addPass(MLPHandle.getPass());
765   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM)));
766   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
767   MPM.run(*M, MAM);
768 }
769 
770 TEST_F(LoopPassManagerTest, IndirectOuterPassInvalidation) {
771   typedef decltype(MLAHandle)::Analysis LoopAnalysis;
772 
773   MockFunctionAnalysisHandle MFAHandle;
774   FAM.registerPass([&] { return MFAHandle.getAnalysis(); });
775   typedef decltype(MFAHandle)::Analysis FunctionAnalysis;
776 
777   // Set up the loop analysis to depend on both the function and module
778   // analysis.
779   ON_CALL(MLAHandle, run(_, _, _))
780       .WillByDefault(Invoke([&](Loop &L, LoopAnalysisManager &AM,
781                                 LoopStandardAnalysisResults &AR) {
782         auto &FAMP = AM.getResult<FunctionAnalysisManagerLoopProxy>(L, AR);
783         auto &FAM = FAMP.getManager();
784         Function &F = *L.getHeader()->getParent();
785         if (FAM.getCachedResult<FunctionAnalysis>(F))
786           FAMP.registerOuterAnalysisInvalidation<FunctionAnalysis,
787                                                  LoopAnalysis>();
788         return MLAHandle.getResult();
789       }));
790 
791   ::testing::InSequence MakeExpectationsSequenced;
792 
793   // Compute the analyses across all of 'f' first.
794   EXPECT_CALL(MFPHandle, run(HasName("f"), _))
795       .WillOnce(Invoke([](Function &F, FunctionAnalysisManager &AM) {
796         // Force the computing of the function analysis so it is available in
797         // this function.
798         (void)AM.getResult<FunctionAnalysis>(F);
799         return PreservedAnalyses::all();
800       }));
801   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
802   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
803   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
804 
805   // Now invalidate the function analysis but preserve the loop analyses.
806   // This should trigger immediate invalidation of the loop analyses, despite
807   // the fact that they were preserved.
808   EXPECT_CALL(MFPHandle, run(HasName("f"), _)).WillOnce(InvokeWithoutArgs([] {
809     auto PA = getLoopPassPreservedAnalyses();
810     if (EnableMSSALoopDependency)
811       PA.preserve<MemorySSAAnalysis>();
812     PA.preserveSet<AllAnalysesOn<Loop>>();
813     return PA;
814   }));
815   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0.0"), _, _));
816   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0.1"), _, _));
817   EXPECT_CALL(MLAHandle, invalidate(HasName("loop.0"), _, _));
818 
819   // And re-running a requires pass recomputes them.
820   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
821   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
822   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
823 
824   // When we run over 'g' we don't populate the cache with the function
825   // analysis.
826   EXPECT_CALL(MFPHandle, run(HasName("g"), _))
827       .WillOnce(Return(PreservedAnalyses::all()));
828   EXPECT_CALL(MLAHandle, run(HasName("loop.g.0"), _, _));
829 
830   // Which means that no extra invalidation occurs and cached values are used.
831   EXPECT_CALL(MFPHandle, run(HasName("g"), _)).WillOnce(InvokeWithoutArgs([] {
832     auto PA = getLoopPassPreservedAnalyses();
833     if (EnableMSSALoopDependency)
834       PA.preserve<MemorySSAAnalysis>();
835     PA.preserveSet<AllAnalysesOn<Loop>>();
836     return PA;
837   }));
838 
839   // Build the pipeline and run it.
840   ModulePassManager MPM(true);
841   FunctionPassManager FPM(true);
842   FPM.addPass(MFPHandle.getPass());
843   FPM.addPass(
844       createFunctionToLoopPassAdaptor(RequireAnalysisLoopPass<LoopAnalysis>()));
845   FPM.addPass(MFPHandle.getPass());
846   FPM.addPass(
847       createFunctionToLoopPassAdaptor(RequireAnalysisLoopPass<LoopAnalysis>()));
848   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
849   MPM.run(*M, MAM);
850 }
851 
852 TEST_F(LoopPassManagerTest, LoopChildInsertion) {
853   // Super boring module with three loops in a single loop nest.
854   M = parseIR(Context, "define void @f(i1* %ptr) {\n"
855                        "entry:\n"
856                        "  br label %loop.0\n"
857                        "loop.0:\n"
858                        "  %cond.0 = load volatile i1, i1* %ptr\n"
859                        "  br i1 %cond.0, label %loop.0.0.ph, label %end\n"
860                        "loop.0.0.ph:\n"
861                        "  br label %loop.0.0\n"
862                        "loop.0.0:\n"
863                        "  %cond.0.0 = load volatile i1, i1* %ptr\n"
864                        "  br i1 %cond.0.0, label %loop.0.0, label %loop.0.1.ph\n"
865                        "loop.0.1.ph:\n"
866                        "  br label %loop.0.1\n"
867                        "loop.0.1:\n"
868                        "  %cond.0.1 = load volatile i1, i1* %ptr\n"
869                        "  br i1 %cond.0.1, label %loop.0.1, label %loop.0.2.ph\n"
870                        "loop.0.2.ph:\n"
871                        "  br label %loop.0.2\n"
872                        "loop.0.2:\n"
873                        "  %cond.0.2 = load volatile i1, i1* %ptr\n"
874                        "  br i1 %cond.0.2, label %loop.0.2, label %loop.0.latch\n"
875                        "loop.0.latch:\n"
876                        "  br label %loop.0\n"
877                        "end:\n"
878                        "  ret void\n"
879                        "}\n");
880 
881   // Build up variables referring into the IR so we can rewrite it below
882   // easily.
883   Function &F = *M->begin();
884   ASSERT_THAT(F, HasName("f"));
885   Argument &Ptr = *F.arg_begin();
886   auto BBI = F.begin();
887   BasicBlock &EntryBB = *BBI++;
888   ASSERT_THAT(EntryBB, HasName("entry"));
889   BasicBlock &Loop0BB = *BBI++;
890   ASSERT_THAT(Loop0BB, HasName("loop.0"));
891   BasicBlock &Loop00PHBB = *BBI++;
892   ASSERT_THAT(Loop00PHBB, HasName("loop.0.0.ph"));
893   BasicBlock &Loop00BB = *BBI++;
894   ASSERT_THAT(Loop00BB, HasName("loop.0.0"));
895   BasicBlock &Loop01PHBB = *BBI++;
896   ASSERT_THAT(Loop01PHBB, HasName("loop.0.1.ph"));
897   BasicBlock &Loop01BB = *BBI++;
898   ASSERT_THAT(Loop01BB, HasName("loop.0.1"));
899   BasicBlock &Loop02PHBB = *BBI++;
900   ASSERT_THAT(Loop02PHBB, HasName("loop.0.2.ph"));
901   BasicBlock &Loop02BB = *BBI++;
902   ASSERT_THAT(Loop02BB, HasName("loop.0.2"));
903   BasicBlock &Loop0LatchBB = *BBI++;
904   ASSERT_THAT(Loop0LatchBB, HasName("loop.0.latch"));
905   BasicBlock &EndBB = *BBI++;
906   ASSERT_THAT(EndBB, HasName("end"));
907   ASSERT_THAT(BBI, F.end());
908   auto CreateCondBr = [&](BasicBlock *TrueBB, BasicBlock *FalseBB,
909                           const char *Name, BasicBlock *BB) {
910     auto *Cond = new LoadInst(Type::getInt1Ty(Context), &Ptr, Name,
911                               /*isVolatile*/ true, BB);
912     BranchInst::Create(TrueBB, FalseBB, Cond, BB);
913   };
914 
915   // Build the pass managers and register our pipeline. We build a single loop
916   // pass pipeline consisting of three mock pass runs over each loop. After
917   // this we run both domtree and loop verification passes to make sure that
918   // the IR remained valid during our mutations.
919   ModulePassManager MPM(true);
920   FunctionPassManager FPM(true);
921   LoopPassManager LPM(true);
922   LPM.addPass(MLPHandle.getPass());
923   LPM.addPass(MLPHandle.getPass());
924   LPM.addPass(MLPHandle.getPass());
925   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM)));
926   FPM.addPass(DominatorTreeVerifierPass());
927   FPM.addPass(LoopVerifierPass());
928   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
929 
930   // All the visit orders are deterministic, so we use simple fully order
931   // expectations.
932   ::testing::InSequence MakeExpectationsSequenced;
933 
934   // We run loop passes three times over each of the loops.
935   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
936       .WillOnce(Invoke(getLoopAnalysisResult));
937   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
938   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
939       .Times(2)
940       .WillRepeatedly(Invoke(getLoopAnalysisResult));
941 
942   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
943       .WillOnce(Invoke(getLoopAnalysisResult));
944   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
945 
946   // When running over the middle loop, the second run inserts two new child
947   // loops, inserting them and itself into the worklist.
948   BasicBlock *NewLoop010BB, *NewLoop01LatchBB;
949   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
950       .WillOnce(Invoke([&](Loop &L, LoopAnalysisManager &AM,
951                            LoopStandardAnalysisResults &AR,
952                            LPMUpdater &Updater) {
953         auto *NewLoop = AR.LI.AllocateLoop();
954         L.addChildLoop(NewLoop);
955         auto *NewLoop010PHBB =
956             BasicBlock::Create(Context, "loop.0.1.0.ph", &F, &Loop02PHBB);
957         NewLoop010BB =
958             BasicBlock::Create(Context, "loop.0.1.0", &F, &Loop02PHBB);
959         NewLoop01LatchBB =
960             BasicBlock::Create(Context, "loop.0.1.latch", &F, &Loop02PHBB);
961         Loop01BB.getTerminator()->replaceUsesOfWith(&Loop01BB, NewLoop010PHBB);
962         BranchInst::Create(NewLoop010BB, NewLoop010PHBB);
963         CreateCondBr(NewLoop01LatchBB, NewLoop010BB, "cond.0.1.0",
964                      NewLoop010BB);
965         BranchInst::Create(&Loop01BB, NewLoop01LatchBB);
966         AR.DT.addNewBlock(NewLoop010PHBB, &Loop01BB);
967         AR.DT.addNewBlock(NewLoop010BB, NewLoop010PHBB);
968         AR.DT.addNewBlock(NewLoop01LatchBB, NewLoop010BB);
969         EXPECT_TRUE(AR.DT.verify());
970         L.addBasicBlockToLoop(NewLoop010PHBB, AR.LI);
971         NewLoop->addBasicBlockToLoop(NewLoop010BB, AR.LI);
972         L.addBasicBlockToLoop(NewLoop01LatchBB, AR.LI);
973         NewLoop->verifyLoop();
974         L.verifyLoop();
975         Updater.addChildLoops({NewLoop});
976         return PreservedAnalyses::all();
977       }));
978 
979   // We should immediately drop down to fully visit the new inner loop.
980   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1.0"), _, _, _))
981       .WillOnce(Invoke(getLoopAnalysisResult));
982   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1.0"), _, _));
983   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1.0"), _, _, _))
984       .Times(2)
985       .WillRepeatedly(Invoke(getLoopAnalysisResult));
986 
987   // After visiting the inner loop, we should re-visit the second loop
988   // reflecting its new loop nest structure.
989   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
990       .WillOnce(Invoke(getLoopAnalysisResult));
991 
992   // In the second run over the middle loop after we've visited the new child,
993   // we add another child to check that we can repeatedly add children, and add
994   // children to a loop that already has children.
995   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
996       .WillOnce(Invoke([&](Loop &L, LoopAnalysisManager &AM,
997                            LoopStandardAnalysisResults &AR,
998                            LPMUpdater &Updater) {
999         auto *NewLoop = AR.LI.AllocateLoop();
1000         L.addChildLoop(NewLoop);
1001         auto *NewLoop011PHBB = BasicBlock::Create(Context, "loop.0.1.1.ph", &F, NewLoop01LatchBB);
1002         auto *NewLoop011BB = BasicBlock::Create(Context, "loop.0.1.1", &F, NewLoop01LatchBB);
1003         NewLoop010BB->getTerminator()->replaceUsesOfWith(NewLoop01LatchBB,
1004                                                          NewLoop011PHBB);
1005         BranchInst::Create(NewLoop011BB, NewLoop011PHBB);
1006         CreateCondBr(NewLoop01LatchBB, NewLoop011BB, "cond.0.1.1",
1007                      NewLoop011BB);
1008         AR.DT.addNewBlock(NewLoop011PHBB, NewLoop010BB);
1009         auto *NewDTNode = AR.DT.addNewBlock(NewLoop011BB, NewLoop011PHBB);
1010         AR.DT.changeImmediateDominator(AR.DT[NewLoop01LatchBB], NewDTNode);
1011         EXPECT_TRUE(AR.DT.verify());
1012         L.addBasicBlockToLoop(NewLoop011PHBB, AR.LI);
1013         NewLoop->addBasicBlockToLoop(NewLoop011BB, AR.LI);
1014         NewLoop->verifyLoop();
1015         L.verifyLoop();
1016         Updater.addChildLoops({NewLoop});
1017         return PreservedAnalyses::all();
1018       }));
1019 
1020   // Again, we should immediately drop down to visit the new, unvisited child
1021   // loop. We don't need to revisit the other child though.
1022   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1.1"), _, _, _))
1023       .WillOnce(Invoke(getLoopAnalysisResult));
1024   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1.1"), _, _));
1025   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1.1"), _, _, _))
1026       .Times(2)
1027       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1028 
1029   // And now we should pop back up to the second loop and do a full pipeline of
1030   // three passes on its current form.
1031   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
1032       .Times(3)
1033       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1034 
1035   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1036       .WillOnce(Invoke(getLoopAnalysisResult));
1037   EXPECT_CALL(MLAHandle, run(HasName("loop.0.2"), _, _));
1038   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1039       .Times(2)
1040       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1041 
1042   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1043       .WillOnce(Invoke(getLoopAnalysisResult));
1044   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
1045   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1046       .Times(2)
1047       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1048 
1049   // Now that all the expected actions are registered, run the pipeline over
1050   // our module. All of our expectations are verified when the test finishes.
1051   MPM.run(*M, MAM);
1052 }
1053 
1054 TEST_F(LoopPassManagerTest, LoopPeerInsertion) {
1055   // Super boring module with two loop nests and loop nest with two child
1056   // loops.
1057   M = parseIR(Context, "define void @f(i1* %ptr) {\n"
1058                        "entry:\n"
1059                        "  br label %loop.0\n"
1060                        "loop.0:\n"
1061                        "  %cond.0 = load volatile i1, i1* %ptr\n"
1062                        "  br i1 %cond.0, label %loop.0.0.ph, label %loop.2.ph\n"
1063                        "loop.0.0.ph:\n"
1064                        "  br label %loop.0.0\n"
1065                        "loop.0.0:\n"
1066                        "  %cond.0.0 = load volatile i1, i1* %ptr\n"
1067                        "  br i1 %cond.0.0, label %loop.0.0, label %loop.0.2.ph\n"
1068                        "loop.0.2.ph:\n"
1069                        "  br label %loop.0.2\n"
1070                        "loop.0.2:\n"
1071                        "  %cond.0.2 = load volatile i1, i1* %ptr\n"
1072                        "  br i1 %cond.0.2, label %loop.0.2, label %loop.0.latch\n"
1073                        "loop.0.latch:\n"
1074                        "  br label %loop.0\n"
1075                        "loop.2.ph:\n"
1076                        "  br label %loop.2\n"
1077                        "loop.2:\n"
1078                        "  %cond.2 = load volatile i1, i1* %ptr\n"
1079                        "  br i1 %cond.2, label %loop.2, label %end\n"
1080                        "end:\n"
1081                        "  ret void\n"
1082                        "}\n");
1083 
1084   // Build up variables referring into the IR so we can rewrite it below
1085   // easily.
1086   Function &F = *M->begin();
1087   ASSERT_THAT(F, HasName("f"));
1088   Argument &Ptr = *F.arg_begin();
1089   auto BBI = F.begin();
1090   BasicBlock &EntryBB = *BBI++;
1091   ASSERT_THAT(EntryBB, HasName("entry"));
1092   BasicBlock &Loop0BB = *BBI++;
1093   ASSERT_THAT(Loop0BB, HasName("loop.0"));
1094   BasicBlock &Loop00PHBB = *BBI++;
1095   ASSERT_THAT(Loop00PHBB, HasName("loop.0.0.ph"));
1096   BasicBlock &Loop00BB = *BBI++;
1097   ASSERT_THAT(Loop00BB, HasName("loop.0.0"));
1098   BasicBlock &Loop02PHBB = *BBI++;
1099   ASSERT_THAT(Loop02PHBB, HasName("loop.0.2.ph"));
1100   BasicBlock &Loop02BB = *BBI++;
1101   ASSERT_THAT(Loop02BB, HasName("loop.0.2"));
1102   BasicBlock &Loop0LatchBB = *BBI++;
1103   ASSERT_THAT(Loop0LatchBB, HasName("loop.0.latch"));
1104   BasicBlock &Loop2PHBB = *BBI++;
1105   ASSERT_THAT(Loop2PHBB, HasName("loop.2.ph"));
1106   BasicBlock &Loop2BB = *BBI++;
1107   ASSERT_THAT(Loop2BB, HasName("loop.2"));
1108   BasicBlock &EndBB = *BBI++;
1109   ASSERT_THAT(EndBB, HasName("end"));
1110   ASSERT_THAT(BBI, F.end());
1111   auto CreateCondBr = [&](BasicBlock *TrueBB, BasicBlock *FalseBB,
1112                           const char *Name, BasicBlock *BB) {
1113     auto *Cond = new LoadInst(Type::getInt1Ty(Context), &Ptr, Name,
1114                               /*isVolatile*/ true, BB);
1115     BranchInst::Create(TrueBB, FalseBB, Cond, BB);
1116   };
1117 
1118   // Build the pass managers and register our pipeline. We build a single loop
1119   // pass pipeline consisting of three mock pass runs over each loop. After
1120   // this we run both domtree and loop verification passes to make sure that
1121   // the IR remained valid during our mutations.
1122   ModulePassManager MPM(true);
1123   FunctionPassManager FPM(true);
1124   LoopPassManager LPM(true);
1125   LPM.addPass(MLPHandle.getPass());
1126   LPM.addPass(MLPHandle.getPass());
1127   LPM.addPass(MLPHandle.getPass());
1128   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM)));
1129   FPM.addPass(DominatorTreeVerifierPass());
1130   FPM.addPass(LoopVerifierPass());
1131   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
1132 
1133   // All the visit orders are deterministic, so we use simple fully order
1134   // expectations.
1135   ::testing::InSequence MakeExpectationsSequenced;
1136 
1137   // We run loop passes three times over each of the loops.
1138   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1139       .WillOnce(Invoke(getLoopAnalysisResult));
1140   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
1141 
1142   // On the second run, we insert a sibling loop.
1143   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1144       .WillOnce(Invoke([&](Loop &L, LoopAnalysisManager &AM,
1145                            LoopStandardAnalysisResults &AR,
1146                            LPMUpdater &Updater) {
1147         auto *NewLoop = AR.LI.AllocateLoop();
1148         L.getParentLoop()->addChildLoop(NewLoop);
1149         auto *NewLoop01PHBB = BasicBlock::Create(Context, "loop.0.1.ph", &F, &Loop02PHBB);
1150         auto *NewLoop01BB = BasicBlock::Create(Context, "loop.0.1", &F, &Loop02PHBB);
1151         BranchInst::Create(NewLoop01BB, NewLoop01PHBB);
1152         CreateCondBr(&Loop02PHBB, NewLoop01BB, "cond.0.1", NewLoop01BB);
1153         Loop00BB.getTerminator()->replaceUsesOfWith(&Loop02PHBB, NewLoop01PHBB);
1154         AR.DT.addNewBlock(NewLoop01PHBB, &Loop00BB);
1155         auto *NewDTNode = AR.DT.addNewBlock(NewLoop01BB, NewLoop01PHBB);
1156         AR.DT.changeImmediateDominator(AR.DT[&Loop02PHBB], NewDTNode);
1157         EXPECT_TRUE(AR.DT.verify());
1158         L.getParentLoop()->addBasicBlockToLoop(NewLoop01PHBB, AR.LI);
1159         NewLoop->addBasicBlockToLoop(NewLoop01BB, AR.LI);
1160         L.getParentLoop()->verifyLoop();
1161         Updater.addSiblingLoops({NewLoop});
1162         return PreservedAnalyses::all();
1163       }));
1164   // We finish processing this loop as sibling loops don't perturb the
1165   // postorder walk.
1166   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1167       .WillOnce(Invoke(getLoopAnalysisResult));
1168 
1169   // We visit the inserted sibling next.
1170   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
1171       .WillOnce(Invoke(getLoopAnalysisResult));
1172   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
1173   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
1174       .Times(2)
1175       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1176 
1177   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1178       .WillOnce(Invoke(getLoopAnalysisResult));
1179   EXPECT_CALL(MLAHandle, run(HasName("loop.0.2"), _, _));
1180   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1181       .WillOnce(Invoke(getLoopAnalysisResult));
1182   // Next, on the third pass run on the last inner loop we add more new
1183   // siblings, more than one, and one with nested child loops. By doing this at
1184   // the end we make sure that edge case works well.
1185   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1186       .WillOnce(Invoke([&](Loop &L, LoopAnalysisManager &AM,
1187                            LoopStandardAnalysisResults &AR,
1188                            LPMUpdater &Updater) {
1189         Loop *NewLoops[] = {AR.LI.AllocateLoop(), AR.LI.AllocateLoop(),
1190                             AR.LI.AllocateLoop()};
1191         L.getParentLoop()->addChildLoop(NewLoops[0]);
1192         L.getParentLoop()->addChildLoop(NewLoops[1]);
1193         NewLoops[1]->addChildLoop(NewLoops[2]);
1194         auto *NewLoop03PHBB =
1195             BasicBlock::Create(Context, "loop.0.3.ph", &F, &Loop0LatchBB);
1196         auto *NewLoop03BB =
1197             BasicBlock::Create(Context, "loop.0.3", &F, &Loop0LatchBB);
1198         auto *NewLoop04PHBB =
1199             BasicBlock::Create(Context, "loop.0.4.ph", &F, &Loop0LatchBB);
1200         auto *NewLoop04BB =
1201             BasicBlock::Create(Context, "loop.0.4", &F, &Loop0LatchBB);
1202         auto *NewLoop040PHBB =
1203             BasicBlock::Create(Context, "loop.0.4.0.ph", &F, &Loop0LatchBB);
1204         auto *NewLoop040BB =
1205             BasicBlock::Create(Context, "loop.0.4.0", &F, &Loop0LatchBB);
1206         auto *NewLoop04LatchBB =
1207             BasicBlock::Create(Context, "loop.0.4.latch", &F, &Loop0LatchBB);
1208         Loop02BB.getTerminator()->replaceUsesOfWith(&Loop0LatchBB, NewLoop03PHBB);
1209         BranchInst::Create(NewLoop03BB, NewLoop03PHBB);
1210         CreateCondBr(NewLoop04PHBB, NewLoop03BB, "cond.0.3", NewLoop03BB);
1211         BranchInst::Create(NewLoop04BB, NewLoop04PHBB);
1212         CreateCondBr(&Loop0LatchBB, NewLoop040PHBB, "cond.0.4", NewLoop04BB);
1213         BranchInst::Create(NewLoop040BB, NewLoop040PHBB);
1214         CreateCondBr(NewLoop04LatchBB, NewLoop040BB, "cond.0.4.0", NewLoop040BB);
1215         BranchInst::Create(NewLoop04BB, NewLoop04LatchBB);
1216         AR.DT.addNewBlock(NewLoop03PHBB, &Loop02BB);
1217         AR.DT.addNewBlock(NewLoop03BB, NewLoop03PHBB);
1218         AR.DT.addNewBlock(NewLoop04PHBB, NewLoop03BB);
1219         auto *NewDTNode = AR.DT.addNewBlock(NewLoop04BB, NewLoop04PHBB);
1220         AR.DT.changeImmediateDominator(AR.DT[&Loop0LatchBB], NewDTNode);
1221         AR.DT.addNewBlock(NewLoop040PHBB, NewLoop04BB);
1222         AR.DT.addNewBlock(NewLoop040BB, NewLoop040PHBB);
1223         AR.DT.addNewBlock(NewLoop04LatchBB, NewLoop040BB);
1224         EXPECT_TRUE(AR.DT.verify());
1225         L.getParentLoop()->addBasicBlockToLoop(NewLoop03PHBB, AR.LI);
1226         NewLoops[0]->addBasicBlockToLoop(NewLoop03BB, AR.LI);
1227         L.getParentLoop()->addBasicBlockToLoop(NewLoop04PHBB, AR.LI);
1228         NewLoops[1]->addBasicBlockToLoop(NewLoop04BB, AR.LI);
1229         NewLoops[1]->addBasicBlockToLoop(NewLoop040PHBB, AR.LI);
1230         NewLoops[2]->addBasicBlockToLoop(NewLoop040BB, AR.LI);
1231         NewLoops[1]->addBasicBlockToLoop(NewLoop04LatchBB, AR.LI);
1232         L.getParentLoop()->verifyLoop();
1233         Updater.addSiblingLoops({NewLoops[0], NewLoops[1]});
1234         return PreservedAnalyses::all();
1235       }));
1236 
1237   EXPECT_CALL(MLPHandle, run(HasName("loop.0.3"), _, _, _))
1238       .WillOnce(Invoke(getLoopAnalysisResult));
1239   EXPECT_CALL(MLAHandle, run(HasName("loop.0.3"), _, _));
1240   EXPECT_CALL(MLPHandle, run(HasName("loop.0.3"), _, _, _))
1241       .Times(2)
1242       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1243 
1244   // Note that we need to visit the inner loop of this added sibling before the
1245   // sibling itself!
1246   EXPECT_CALL(MLPHandle, run(HasName("loop.0.4.0"), _, _, _))
1247       .WillOnce(Invoke(getLoopAnalysisResult));
1248   EXPECT_CALL(MLAHandle, run(HasName("loop.0.4.0"), _, _));
1249   EXPECT_CALL(MLPHandle, run(HasName("loop.0.4.0"), _, _, _))
1250       .Times(2)
1251       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1252 
1253   EXPECT_CALL(MLPHandle, run(HasName("loop.0.4"), _, _, _))
1254       .WillOnce(Invoke(getLoopAnalysisResult));
1255   EXPECT_CALL(MLAHandle, run(HasName("loop.0.4"), _, _));
1256   EXPECT_CALL(MLPHandle, run(HasName("loop.0.4"), _, _, _))
1257       .Times(2)
1258       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1259 
1260   // And only now do we visit the outermost loop of the nest.
1261   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1262       .WillOnce(Invoke(getLoopAnalysisResult));
1263   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
1264   // On the second pass, we add sibling loops which become new top-level loops.
1265   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1266       .WillOnce(Invoke([&](Loop &L, LoopAnalysisManager &AM,
1267                            LoopStandardAnalysisResults &AR,
1268                            LPMUpdater &Updater) {
1269         auto *NewLoop = AR.LI.AllocateLoop();
1270         AR.LI.addTopLevelLoop(NewLoop);
1271         auto *NewLoop1PHBB = BasicBlock::Create(Context, "loop.1.ph", &F, &Loop2BB);
1272         auto *NewLoop1BB = BasicBlock::Create(Context, "loop.1", &F, &Loop2BB);
1273         BranchInst::Create(NewLoop1BB, NewLoop1PHBB);
1274         CreateCondBr(&Loop2PHBB, NewLoop1BB, "cond.1", NewLoop1BB);
1275         Loop0BB.getTerminator()->replaceUsesOfWith(&Loop2PHBB, NewLoop1PHBB);
1276         AR.DT.addNewBlock(NewLoop1PHBB, &Loop0BB);
1277         auto *NewDTNode = AR.DT.addNewBlock(NewLoop1BB, NewLoop1PHBB);
1278         AR.DT.changeImmediateDominator(AR.DT[&Loop2PHBB], NewDTNode);
1279         EXPECT_TRUE(AR.DT.verify());
1280         NewLoop->addBasicBlockToLoop(NewLoop1BB, AR.LI);
1281         NewLoop->verifyLoop();
1282         Updater.addSiblingLoops({NewLoop});
1283         return PreservedAnalyses::all();
1284       }));
1285   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1286       .WillOnce(Invoke(getLoopAnalysisResult));
1287 
1288   EXPECT_CALL(MLPHandle, run(HasName("loop.1"), _, _, _))
1289       .WillOnce(Invoke(getLoopAnalysisResult));
1290   EXPECT_CALL(MLAHandle, run(HasName("loop.1"), _, _));
1291   EXPECT_CALL(MLPHandle, run(HasName("loop.1"), _, _, _))
1292       .Times(2)
1293       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1294 
1295   EXPECT_CALL(MLPHandle, run(HasName("loop.2"), _, _, _))
1296       .WillOnce(Invoke(getLoopAnalysisResult));
1297   EXPECT_CALL(MLAHandle, run(HasName("loop.2"), _, _));
1298   EXPECT_CALL(MLPHandle, run(HasName("loop.2"), _, _, _))
1299       .Times(2)
1300       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1301 
1302   // Now that all the expected actions are registered, run the pipeline over
1303   // our module. All of our expectations are verified when the test finishes.
1304   MPM.run(*M, MAM);
1305 }
1306 
1307 TEST_F(LoopPassManagerTest, LoopDeletion) {
1308   // Build a module with a single loop nest that contains one outer loop with
1309   // three subloops, and one of those with its own subloop. We will
1310   // incrementally delete all of these to test different deletion scenarios.
1311   M = parseIR(Context, "define void @f(i1* %ptr) {\n"
1312                        "entry:\n"
1313                        "  br label %loop.0\n"
1314                        "loop.0:\n"
1315                        "  %cond.0 = load volatile i1, i1* %ptr\n"
1316                        "  br i1 %cond.0, label %loop.0.0.ph, label %end\n"
1317                        "loop.0.0.ph:\n"
1318                        "  br label %loop.0.0\n"
1319                        "loop.0.0:\n"
1320                        "  %cond.0.0 = load volatile i1, i1* %ptr\n"
1321                        "  br i1 %cond.0.0, label %loop.0.0, label %loop.0.1.ph\n"
1322                        "loop.0.1.ph:\n"
1323                        "  br label %loop.0.1\n"
1324                        "loop.0.1:\n"
1325                        "  %cond.0.1 = load volatile i1, i1* %ptr\n"
1326                        "  br i1 %cond.0.1, label %loop.0.1, label %loop.0.2.ph\n"
1327                        "loop.0.2.ph:\n"
1328                        "  br label %loop.0.2\n"
1329                        "loop.0.2:\n"
1330                        "  %cond.0.2 = load volatile i1, i1* %ptr\n"
1331                        "  br i1 %cond.0.2, label %loop.0.2.0.ph, label %loop.0.latch\n"
1332                        "loop.0.2.0.ph:\n"
1333                        "  br label %loop.0.2.0\n"
1334                        "loop.0.2.0:\n"
1335                        "  %cond.0.2.0 = load volatile i1, i1* %ptr\n"
1336                        "  br i1 %cond.0.2.0, label %loop.0.2.0, label %loop.0.2.latch\n"
1337                        "loop.0.2.latch:\n"
1338                        "  br label %loop.0.2\n"
1339                        "loop.0.latch:\n"
1340                        "  br label %loop.0\n"
1341                        "end:\n"
1342                        "  ret void\n"
1343                        "}\n");
1344 
1345   // Build up variables referring into the IR so we can rewrite it below
1346   // easily.
1347   Function &F = *M->begin();
1348   ASSERT_THAT(F, HasName("f"));
1349   Argument &Ptr = *F.arg_begin();
1350   auto BBI = F.begin();
1351   BasicBlock &EntryBB = *BBI++;
1352   ASSERT_THAT(EntryBB, HasName("entry"));
1353   BasicBlock &Loop0BB = *BBI++;
1354   ASSERT_THAT(Loop0BB, HasName("loop.0"));
1355   BasicBlock &Loop00PHBB = *BBI++;
1356   ASSERT_THAT(Loop00PHBB, HasName("loop.0.0.ph"));
1357   BasicBlock &Loop00BB = *BBI++;
1358   ASSERT_THAT(Loop00BB, HasName("loop.0.0"));
1359   BasicBlock &Loop01PHBB = *BBI++;
1360   ASSERT_THAT(Loop01PHBB, HasName("loop.0.1.ph"));
1361   BasicBlock &Loop01BB = *BBI++;
1362   ASSERT_THAT(Loop01BB, HasName("loop.0.1"));
1363   BasicBlock &Loop02PHBB = *BBI++;
1364   ASSERT_THAT(Loop02PHBB, HasName("loop.0.2.ph"));
1365   BasicBlock &Loop02BB = *BBI++;
1366   ASSERT_THAT(Loop02BB, HasName("loop.0.2"));
1367   BasicBlock &Loop020PHBB = *BBI++;
1368   ASSERT_THAT(Loop020PHBB, HasName("loop.0.2.0.ph"));
1369   BasicBlock &Loop020BB = *BBI++;
1370   ASSERT_THAT(Loop020BB, HasName("loop.0.2.0"));
1371   BasicBlock &Loop02LatchBB = *BBI++;
1372   ASSERT_THAT(Loop02LatchBB, HasName("loop.0.2.latch"));
1373   BasicBlock &Loop0LatchBB = *BBI++;
1374   ASSERT_THAT(Loop0LatchBB, HasName("loop.0.latch"));
1375   BasicBlock &EndBB = *BBI++;
1376   ASSERT_THAT(EndBB, HasName("end"));
1377   ASSERT_THAT(BBI, F.end());
1378 
1379   // Helper to do the actual deletion of a loop. We directly encode this here
1380   // to isolate ourselves from the rest of LLVM and for simplicity. Here we can
1381   // egregiously cheat based on knowledge of the test case. For example, we
1382   // have no PHI nodes and there is always a single i-dom.
1383   auto EraseLoop = [](Loop &L, BasicBlock &IDomBB,
1384                       LoopStandardAnalysisResults &AR, LPMUpdater &Updater) {
1385     assert(L.empty() && "Can only delete leaf loops with this routine!");
1386     SmallVector<BasicBlock *, 4> LoopBBs(L.block_begin(), L.block_end());
1387     Updater.markLoopAsDeleted(L, L.getName());
1388     IDomBB.getTerminator()->replaceUsesOfWith(L.getHeader(),
1389                                               L.getUniqueExitBlock());
1390     for (BasicBlock *LoopBB : LoopBBs) {
1391       SmallVector<DomTreeNode *, 4> ChildNodes(AR.DT[LoopBB]->begin(),
1392                                                AR.DT[LoopBB]->end());
1393       for (DomTreeNode *ChildNode : ChildNodes)
1394         AR.DT.changeImmediateDominator(ChildNode, AR.DT[&IDomBB]);
1395       AR.DT.eraseNode(LoopBB);
1396       AR.LI.removeBlock(LoopBB);
1397       LoopBB->dropAllReferences();
1398     }
1399     for (BasicBlock *LoopBB : LoopBBs)
1400       LoopBB->eraseFromParent();
1401 
1402     AR.LI.erase(&L);
1403   };
1404 
1405   // Build up the pass managers.
1406   ModulePassManager MPM(true);
1407   FunctionPassManager FPM(true);
1408   // We run several loop pass pipelines across the loop nest, but they all take
1409   // the same form of three mock pass runs in a loop pipeline followed by
1410   // domtree and loop verification. We use a lambda to stamp this out each
1411   // time.
1412   auto AddLoopPipelineAndVerificationPasses = [&] {
1413     LoopPassManager LPM(true);
1414     LPM.addPass(MLPHandle.getPass());
1415     LPM.addPass(MLPHandle.getPass());
1416     LPM.addPass(MLPHandle.getPass());
1417     FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM)));
1418     FPM.addPass(DominatorTreeVerifierPass());
1419     FPM.addPass(LoopVerifierPass());
1420   };
1421 
1422   // All the visit orders are deterministic so we use simple fully order
1423   // expectations.
1424   ::testing::InSequence MakeExpectationsSequenced;
1425 
1426   // We run the loop pipeline with three passes over each of the loops. When
1427   // running over the middle loop, the second pass in the pipeline deletes it.
1428   // This should prevent the third pass from visiting it but otherwise leave
1429   // the process unimpacted.
1430   AddLoopPipelineAndVerificationPasses();
1431   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1432       .WillOnce(Invoke(getLoopAnalysisResult));
1433   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
1434   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1435       .Times(2)
1436       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1437 
1438   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
1439       .WillOnce(Invoke(getLoopAnalysisResult));
1440   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
1441   EXPECT_CALL(MLPHandle, run(HasName("loop.0.1"), _, _, _))
1442       .WillOnce(
1443           Invoke([&](Loop &L, LoopAnalysisManager &AM,
1444                      LoopStandardAnalysisResults &AR, LPMUpdater &Updater) {
1445             Loop *ParentL = L.getParentLoop();
1446             AR.SE.forgetLoop(&L);
1447             EraseLoop(L, Loop01PHBB, AR, Updater);
1448             ParentL->verifyLoop();
1449             return PreservedAnalyses::all();
1450           }));
1451 
1452   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2.0"), _, _, _))
1453       .WillOnce(Invoke(getLoopAnalysisResult));
1454   EXPECT_CALL(MLAHandle, run(HasName("loop.0.2.0"), _, _));
1455   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2.0"), _, _, _))
1456       .Times(2)
1457       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1458 
1459   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1460       .WillOnce(Invoke(getLoopAnalysisResult));
1461   EXPECT_CALL(MLAHandle, run(HasName("loop.0.2"), _, _));
1462   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1463       .Times(2)
1464       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1465 
1466   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1467       .WillOnce(Invoke(getLoopAnalysisResult));
1468   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));
1469   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1470       .Times(2)
1471       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1472 
1473   // Run the loop pipeline again. This time we delete the last loop, which
1474   // contains a nested loop within it and insert a new loop into the nest. This
1475   // makes sure we can handle nested loop deletion.
1476   AddLoopPipelineAndVerificationPasses();
1477   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1478       .Times(3)
1479       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1480 
1481   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2.0"), _, _, _))
1482       .Times(3)
1483       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1484 
1485   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1486       .WillOnce(Invoke(getLoopAnalysisResult));
1487   BasicBlock *NewLoop03PHBB;
1488   EXPECT_CALL(MLPHandle, run(HasName("loop.0.2"), _, _, _))
1489       .WillOnce(
1490           Invoke([&](Loop &L, LoopAnalysisManager &AM,
1491                      LoopStandardAnalysisResults &AR, LPMUpdater &Updater) {
1492             AR.SE.forgetLoop(*L.begin());
1493             EraseLoop(**L.begin(), Loop020PHBB, AR, Updater);
1494 
1495             auto *ParentL = L.getParentLoop();
1496             AR.SE.forgetLoop(&L);
1497             EraseLoop(L, Loop02PHBB, AR, Updater);
1498 
1499             // Now insert a new sibling loop.
1500             auto *NewSibling = AR.LI.AllocateLoop();
1501             ParentL->addChildLoop(NewSibling);
1502             NewLoop03PHBB =
1503                 BasicBlock::Create(Context, "loop.0.3.ph", &F, &Loop0LatchBB);
1504             auto *NewLoop03BB =
1505                 BasicBlock::Create(Context, "loop.0.3", &F, &Loop0LatchBB);
1506             BranchInst::Create(NewLoop03BB, NewLoop03PHBB);
1507             auto *Cond =
1508                 new LoadInst(Type::getInt1Ty(Context), &Ptr, "cond.0.3",
1509                              /*isVolatile*/ true, NewLoop03BB);
1510             BranchInst::Create(&Loop0LatchBB, NewLoop03BB, Cond, NewLoop03BB);
1511             Loop02PHBB.getTerminator()->replaceUsesOfWith(&Loop0LatchBB,
1512                                                           NewLoop03PHBB);
1513             AR.DT.addNewBlock(NewLoop03PHBB, &Loop02PHBB);
1514             AR.DT.addNewBlock(NewLoop03BB, NewLoop03PHBB);
1515             AR.DT.changeImmediateDominator(AR.DT[&Loop0LatchBB],
1516                                            AR.DT[NewLoop03BB]);
1517             EXPECT_TRUE(AR.DT.verify());
1518             ParentL->addBasicBlockToLoop(NewLoop03PHBB, AR.LI);
1519             NewSibling->addBasicBlockToLoop(NewLoop03BB, AR.LI);
1520             NewSibling->verifyLoop();
1521             ParentL->verifyLoop();
1522             Updater.addSiblingLoops({NewSibling});
1523             return PreservedAnalyses::all();
1524           }));
1525 
1526   // To respect our inner-to-outer traversal order, we must visit the
1527   // newly-inserted sibling of the loop we just deleted before we visit the
1528   // outer loop. When we do so, this must compute a fresh analysis result, even
1529   // though our new loop has the same pointer value as the loop we deleted.
1530   EXPECT_CALL(MLPHandle, run(HasName("loop.0.3"), _, _, _))
1531       .WillOnce(Invoke(getLoopAnalysisResult));
1532   EXPECT_CALL(MLAHandle, run(HasName("loop.0.3"), _, _));
1533   EXPECT_CALL(MLPHandle, run(HasName("loop.0.3"), _, _, _))
1534       .Times(2)
1535       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1536 
1537   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1538       .Times(3)
1539       .WillRepeatedly(Invoke(getLoopAnalysisResult));
1540 
1541   // In the final loop pipeline run we delete every loop, including the last
1542   // loop of the nest. We do this again in the second pass in the pipeline, and
1543   // as a consequence we never make it to three runs on any loop. We also cover
1544   // deleting multiple loops in a single pipeline, deleting the first loop and
1545   // deleting the (last) top level loop.
1546   AddLoopPipelineAndVerificationPasses();
1547   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1548       .WillOnce(Invoke(getLoopAnalysisResult));
1549   EXPECT_CALL(MLPHandle, run(HasName("loop.0.0"), _, _, _))
1550       .WillOnce(
1551           Invoke([&](Loop &L, LoopAnalysisManager &AM,
1552                      LoopStandardAnalysisResults &AR, LPMUpdater &Updater) {
1553             AR.SE.forgetLoop(&L);
1554             EraseLoop(L, Loop00PHBB, AR, Updater);
1555             return PreservedAnalyses::all();
1556           }));
1557 
1558   EXPECT_CALL(MLPHandle, run(HasName("loop.0.3"), _, _, _))
1559       .WillOnce(Invoke(getLoopAnalysisResult));
1560   EXPECT_CALL(MLPHandle, run(HasName("loop.0.3"), _, _, _))
1561       .WillOnce(
1562           Invoke([&](Loop &L, LoopAnalysisManager &AM,
1563                      LoopStandardAnalysisResults &AR, LPMUpdater &Updater) {
1564             AR.SE.forgetLoop(&L);
1565             EraseLoop(L, *NewLoop03PHBB, AR, Updater);
1566             return PreservedAnalyses::all();
1567           }));
1568 
1569   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1570       .WillOnce(Invoke(getLoopAnalysisResult));
1571   EXPECT_CALL(MLPHandle, run(HasName("loop.0"), _, _, _))
1572       .WillOnce(
1573           Invoke([&](Loop &L, LoopAnalysisManager &AM,
1574                      LoopStandardAnalysisResults &AR, LPMUpdater &Updater) {
1575             AR.SE.forgetLoop(&L);
1576             EraseLoop(L, EntryBB, AR, Updater);
1577             return PreservedAnalyses::all();
1578           }));
1579 
1580   // Add the function pass pipeline now that it is fully built up and run it
1581   // over the module's one function.
1582   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
1583   MPM.run(*M, MAM);
1584 }
1585 }
1586