1 //===- TestPatterns.cpp - Test dialect pattern driver ---------------------===//
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 "TestDialect.h"
10 #include "mlir/Dialect/StandardOps/IR/Ops.h"
11 #include "mlir/Dialect/StandardOps/Transforms/FuncConversions.h"
12 #include "mlir/Dialect/Tensor/IR/Tensor.h"
13 #include "mlir/IR/Matchers.h"
14 #include "mlir/Pass/Pass.h"
15 #include "mlir/Transforms/DialectConversion.h"
16 #include "mlir/Transforms/FoldUtils.h"
17 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
18 
19 using namespace mlir;
20 using namespace test;
21 
22 // Native function for testing NativeCodeCall
23 static Value chooseOperand(Value input1, Value input2, BoolAttr choice) {
24   return choice.getValue() ? input1 : input2;
25 }
26 
27 static void createOpI(PatternRewriter &rewriter, Location loc, Value input) {
28   rewriter.create<OpI>(loc, input);
29 }
30 
31 static void handleNoResultOp(PatternRewriter &rewriter,
32                              OpSymbolBindingNoResult op) {
33   // Turn the no result op to a one-result op.
34   rewriter.create<OpSymbolBindingB>(op.getLoc(), op.operand().getType(),
35                                     op.operand());
36 }
37 
38 static bool getFirstI32Result(Operation *op, Value &value) {
39   if (!Type(op->getResult(0).getType()).isSignlessInteger(32))
40     return false;
41   value = op->getResult(0);
42   return true;
43 }
44 
45 static Value bindNativeCodeCallResult(Value value) { return value; }
46 
47 static SmallVector<Value, 2> bindMultipleNativeCodeCallResult(Value input1,
48                                                               Value input2) {
49   return SmallVector<Value, 2>({input2, input1});
50 }
51 
52 // Test that natives calls are only called once during rewrites.
53 // OpM_Test will return Pi, increased by 1 for each subsequent calls.
54 // This let us check the number of times OpM_Test was called by inspecting
55 // the returned value in the MLIR output.
56 static int64_t opMIncreasingValue = 314159265;
57 static Attribute OpMTest(PatternRewriter &rewriter, Value val) {
58   int64_t i = opMIncreasingValue++;
59   return rewriter.getIntegerAttr(rewriter.getIntegerType(32), i);
60 }
61 
62 namespace {
63 #include "TestPatterns.inc"
64 } // end anonymous namespace
65 
66 //===----------------------------------------------------------------------===//
67 // Test Reduce Pattern Interface
68 //===----------------------------------------------------------------------===//
69 
70 void test::populateTestReductionPatterns(RewritePatternSet &patterns) {
71   populateWithGenerated(patterns);
72 }
73 
74 //===----------------------------------------------------------------------===//
75 // Canonicalizer Driver.
76 //===----------------------------------------------------------------------===//
77 
78 namespace {
79 struct FoldingPattern : public RewritePattern {
80 public:
81   FoldingPattern(MLIRContext *context)
82       : RewritePattern(TestOpInPlaceFoldAnchor::getOperationName(),
83                        /*benefit=*/1, context) {}
84 
85   LogicalResult matchAndRewrite(Operation *op,
86                                 PatternRewriter &rewriter) const override {
87     // Exercise OperationFolder API for a single-result operation that is folded
88     // upon construction. The operation being created through the folder has an
89     // in-place folder, and it should be still present in the output.
90     // Furthermore, the folder should not crash when attempting to recover the
91     // (unchanged) operation result.
92     OperationFolder folder(op->getContext());
93     Value result = folder.create<TestOpInPlaceFold>(
94         rewriter, op->getLoc(), rewriter.getIntegerType(32), op->getOperand(0),
95         rewriter.getI32IntegerAttr(0));
96     assert(result);
97     rewriter.replaceOp(op, result);
98     return success();
99   }
100 };
101 
102 /// This pattern creates a foldable operation at the entry point of the block.
103 /// This tests the situation where the operation folder will need to replace an
104 /// operation with a previously created constant that does not initially
105 /// dominate the operation to replace.
106 struct FolderInsertBeforePreviouslyFoldedConstantPattern
107     : public OpRewritePattern<TestCastOp> {
108 public:
109   using OpRewritePattern<TestCastOp>::OpRewritePattern;
110 
111   LogicalResult matchAndRewrite(TestCastOp op,
112                                 PatternRewriter &rewriter) const override {
113     if (!op->hasAttr("test_fold_before_previously_folded_op"))
114       return failure();
115     rewriter.setInsertionPointToStart(op->getBlock());
116 
117     auto constOp =
118         rewriter.create<ConstantOp>(op.getLoc(), rewriter.getBoolAttr(true));
119     rewriter.replaceOpWithNewOp<TestCastOp>(op, rewriter.getI32Type(),
120                                             Value(constOp));
121     return success();
122   }
123 };
124 
125 struct TestPatternDriver : public PassWrapper<TestPatternDriver, FunctionPass> {
126   StringRef getArgument() const final { return "test-patterns"; }
127   StringRef getDescription() const final { return "Run test dialect patterns"; }
128   void runOnFunction() override {
129     mlir::RewritePatternSet patterns(&getContext());
130     populateWithGenerated(patterns);
131 
132     // Verify named pattern is generated with expected name.
133     patterns.add<FoldingPattern, TestNamedPatternRule,
134                  FolderInsertBeforePreviouslyFoldedConstantPattern>(
135         &getContext());
136 
137     (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
138   }
139 };
140 } // end anonymous namespace
141 
142 //===----------------------------------------------------------------------===//
143 // ReturnType Driver.
144 //===----------------------------------------------------------------------===//
145 
146 namespace {
147 // Generate ops for each instance where the type can be successfully inferred.
148 template <typename OpTy>
149 static void invokeCreateWithInferredReturnType(Operation *op) {
150   auto *context = op->getContext();
151   auto fop = op->getParentOfType<FuncOp>();
152   auto location = UnknownLoc::get(context);
153   OpBuilder b(op);
154   b.setInsertionPointAfter(op);
155 
156   // Use permutations of 2 args as operands.
157   assert(fop.getNumArguments() >= 2);
158   for (int i = 0, e = fop.getNumArguments(); i < e; ++i) {
159     for (int j = 0; j < e; ++j) {
160       std::array<Value, 2> values = {{fop.getArgument(i), fop.getArgument(j)}};
161       SmallVector<Type, 2> inferredReturnTypes;
162       if (succeeded(OpTy::inferReturnTypes(
163               context, llvm::None, values, op->getAttrDictionary(),
164               op->getRegions(), inferredReturnTypes))) {
165         OperationState state(location, OpTy::getOperationName());
166         // TODO: Expand to regions.
167         OpTy::build(b, state, values, op->getAttrs());
168         (void)b.createOperation(state);
169       }
170     }
171   }
172 }
173 
174 static void reifyReturnShape(Operation *op) {
175   OpBuilder b(op);
176 
177   // Use permutations of 2 args as operands.
178   auto shapedOp = cast<OpWithShapedTypeInferTypeInterfaceOp>(op);
179   SmallVector<Value, 2> shapes;
180   if (failed(shapedOp.reifyReturnTypeShapes(b, op->getOperands(), shapes)) ||
181       !llvm::hasSingleElement(shapes))
182     return;
183   for (auto it : llvm::enumerate(shapes)) {
184     op->emitRemark() << "value " << it.index() << ": "
185                      << it.value().getDefiningOp();
186   }
187 }
188 
189 struct TestReturnTypeDriver
190     : public PassWrapper<TestReturnTypeDriver, FunctionPass> {
191   void getDependentDialects(DialectRegistry &registry) const override {
192     registry.insert<tensor::TensorDialect>();
193   }
194   StringRef getArgument() const final { return "test-return-type"; }
195   StringRef getDescription() const final { return "Run return type functions"; }
196 
197   void runOnFunction() override {
198     if (getFunction().getName() == "testCreateFunctions") {
199       std::vector<Operation *> ops;
200       // Collect ops to avoid triggering on inserted ops.
201       for (auto &op : getFunction().getBody().front())
202         ops.push_back(&op);
203       // Generate test patterns for each, but skip terminator.
204       for (auto *op : llvm::makeArrayRef(ops).drop_back()) {
205         // Test create method of each of the Op classes below. The resultant
206         // output would be in reverse order underneath `op` from which
207         // the attributes and regions are used.
208         invokeCreateWithInferredReturnType<OpWithInferTypeInterfaceOp>(op);
209         invokeCreateWithInferredReturnType<
210             OpWithShapedTypeInferTypeInterfaceOp>(op);
211       };
212       return;
213     }
214     if (getFunction().getName() == "testReifyFunctions") {
215       std::vector<Operation *> ops;
216       // Collect ops to avoid triggering on inserted ops.
217       for (auto &op : getFunction().getBody().front())
218         if (isa<OpWithShapedTypeInferTypeInterfaceOp>(op))
219           ops.push_back(&op);
220       // Generate test patterns for each, but skip terminator.
221       for (auto *op : ops)
222         reifyReturnShape(op);
223     }
224   }
225 };
226 } // end anonymous namespace
227 
228 namespace {
229 struct TestDerivedAttributeDriver
230     : public PassWrapper<TestDerivedAttributeDriver, FunctionPass> {
231   StringRef getArgument() const final { return "test-derived-attr"; }
232   StringRef getDescription() const final {
233     return "Run test derived attributes";
234   }
235   void runOnFunction() override;
236 };
237 } // end anonymous namespace
238 
239 void TestDerivedAttributeDriver::runOnFunction() {
240   getFunction().walk([](DerivedAttributeOpInterface dOp) {
241     auto dAttr = dOp.materializeDerivedAttributes();
242     if (!dAttr)
243       return;
244     for (auto d : dAttr)
245       dOp.emitRemark() << d.first << " = " << d.second;
246   });
247 }
248 
249 //===----------------------------------------------------------------------===//
250 // Legalization Driver.
251 //===----------------------------------------------------------------------===//
252 
253 namespace {
254 //===----------------------------------------------------------------------===//
255 // Region-Block Rewrite Testing
256 
257 /// This pattern is a simple pattern that inlines the first region of a given
258 /// operation into the parent region.
259 struct TestRegionRewriteBlockMovement : public ConversionPattern {
260   TestRegionRewriteBlockMovement(MLIRContext *ctx)
261       : ConversionPattern("test.region", 1, ctx) {}
262 
263   LogicalResult
264   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
265                   ConversionPatternRewriter &rewriter) const final {
266     // Inline this region into the parent region.
267     auto &parentRegion = *op->getParentRegion();
268     auto &opRegion = op->getRegion(0);
269     if (op->getAttr("legalizer.should_clone"))
270       rewriter.cloneRegionBefore(opRegion, parentRegion, parentRegion.end());
271     else
272       rewriter.inlineRegionBefore(opRegion, parentRegion, parentRegion.end());
273 
274     if (op->getAttr("legalizer.erase_old_blocks")) {
275       while (!opRegion.empty())
276         rewriter.eraseBlock(&opRegion.front());
277     }
278 
279     // Drop this operation.
280     rewriter.eraseOp(op);
281     return success();
282   }
283 };
284 /// This pattern is a simple pattern that generates a region containing an
285 /// illegal operation.
286 struct TestRegionRewriteUndo : public RewritePattern {
287   TestRegionRewriteUndo(MLIRContext *ctx)
288       : RewritePattern("test.region_builder", 1, ctx) {}
289 
290   LogicalResult matchAndRewrite(Operation *op,
291                                 PatternRewriter &rewriter) const final {
292     // Create the region operation with an entry block containing arguments.
293     OperationState newRegion(op->getLoc(), "test.region");
294     newRegion.addRegion();
295     auto *regionOp = rewriter.createOperation(newRegion);
296     auto *entryBlock = rewriter.createBlock(&regionOp->getRegion(0));
297     entryBlock->addArgument(rewriter.getIntegerType(64));
298 
299     // Add an explicitly illegal operation to ensure the conversion fails.
300     rewriter.create<ILLegalOpF>(op->getLoc(), rewriter.getIntegerType(32));
301     rewriter.create<TestValidOp>(op->getLoc(), ArrayRef<Value>());
302 
303     // Drop this operation.
304     rewriter.eraseOp(op);
305     return success();
306   }
307 };
308 /// A simple pattern that creates a block at the end of the parent region of the
309 /// matched operation.
310 struct TestCreateBlock : public RewritePattern {
311   TestCreateBlock(MLIRContext *ctx)
312       : RewritePattern("test.create_block", /*benefit=*/1, ctx) {}
313 
314   LogicalResult matchAndRewrite(Operation *op,
315                                 PatternRewriter &rewriter) const final {
316     Region &region = *op->getParentRegion();
317     Type i32Type = rewriter.getIntegerType(32);
318     rewriter.createBlock(&region, region.end(), {i32Type, i32Type});
319     rewriter.create<TerminatorOp>(op->getLoc());
320     rewriter.replaceOp(op, {});
321     return success();
322   }
323 };
324 
325 /// A simple pattern that creates a block containing an invalid operation in
326 /// order to trigger the block creation undo mechanism.
327 struct TestCreateIllegalBlock : public RewritePattern {
328   TestCreateIllegalBlock(MLIRContext *ctx)
329       : RewritePattern("test.create_illegal_block", /*benefit=*/1, ctx) {}
330 
331   LogicalResult matchAndRewrite(Operation *op,
332                                 PatternRewriter &rewriter) const final {
333     Region &region = *op->getParentRegion();
334     Type i32Type = rewriter.getIntegerType(32);
335     rewriter.createBlock(&region, region.end(), {i32Type, i32Type});
336     // Create an illegal op to ensure the conversion fails.
337     rewriter.create<ILLegalOpF>(op->getLoc(), i32Type);
338     rewriter.create<TerminatorOp>(op->getLoc());
339     rewriter.replaceOp(op, {});
340     return success();
341   }
342 };
343 
344 /// A simple pattern that tests the undo mechanism when replacing the uses of a
345 /// block argument.
346 struct TestUndoBlockArgReplace : public ConversionPattern {
347   TestUndoBlockArgReplace(MLIRContext *ctx)
348       : ConversionPattern("test.undo_block_arg_replace", /*benefit=*/1, ctx) {}
349 
350   LogicalResult
351   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
352                   ConversionPatternRewriter &rewriter) const final {
353     auto illegalOp =
354         rewriter.create<ILLegalOpF>(op->getLoc(), rewriter.getF32Type());
355     rewriter.replaceUsesOfBlockArgument(op->getRegion(0).getArgument(0),
356                                         illegalOp);
357     rewriter.updateRootInPlace(op, [] {});
358     return success();
359   }
360 };
361 
362 /// A rewrite pattern that tests the undo mechanism when erasing a block.
363 struct TestUndoBlockErase : public ConversionPattern {
364   TestUndoBlockErase(MLIRContext *ctx)
365       : ConversionPattern("test.undo_block_erase", /*benefit=*/1, ctx) {}
366 
367   LogicalResult
368   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
369                   ConversionPatternRewriter &rewriter) const final {
370     Block *secondBlock = &*std::next(op->getRegion(0).begin());
371     rewriter.setInsertionPointToStart(secondBlock);
372     rewriter.create<ILLegalOpF>(op->getLoc(), rewriter.getF32Type());
373     rewriter.eraseBlock(secondBlock);
374     rewriter.updateRootInPlace(op, [] {});
375     return success();
376   }
377 };
378 
379 //===----------------------------------------------------------------------===//
380 // Type-Conversion Rewrite Testing
381 
382 /// This patterns erases a region operation that has had a type conversion.
383 struct TestDropOpSignatureConversion : public ConversionPattern {
384   TestDropOpSignatureConversion(MLIRContext *ctx, TypeConverter &converter)
385       : ConversionPattern(converter, "test.drop_region_op", 1, ctx) {}
386   LogicalResult
387   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
388                   ConversionPatternRewriter &rewriter) const override {
389     Region &region = op->getRegion(0);
390     Block *entry = &region.front();
391 
392     // Convert the original entry arguments.
393     TypeConverter &converter = *getTypeConverter();
394     TypeConverter::SignatureConversion result(entry->getNumArguments());
395     if (failed(converter.convertSignatureArgs(entry->getArgumentTypes(),
396                                               result)) ||
397         failed(rewriter.convertRegionTypes(&region, converter, &result)))
398       return failure();
399 
400     // Convert the region signature and just drop the operation.
401     rewriter.eraseOp(op);
402     return success();
403   }
404 };
405 /// This pattern simply updates the operands of the given operation.
406 struct TestPassthroughInvalidOp : public ConversionPattern {
407   TestPassthroughInvalidOp(MLIRContext *ctx)
408       : ConversionPattern("test.invalid", 1, ctx) {}
409   LogicalResult
410   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
411                   ConversionPatternRewriter &rewriter) const final {
412     rewriter.replaceOpWithNewOp<TestValidOp>(op, llvm::None, operands,
413                                              llvm::None);
414     return success();
415   }
416 };
417 /// This pattern handles the case of a split return value.
418 struct TestSplitReturnType : public ConversionPattern {
419   TestSplitReturnType(MLIRContext *ctx)
420       : ConversionPattern("test.return", 1, ctx) {}
421   LogicalResult
422   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
423                   ConversionPatternRewriter &rewriter) const final {
424     // Check for a return of F32.
425     if (op->getNumOperands() != 1 || !op->getOperand(0).getType().isF32())
426       return failure();
427 
428     // Check if the first operation is a cast operation, if it is we use the
429     // results directly.
430     auto *defOp = operands[0].getDefiningOp();
431     if (auto packerOp = llvm::dyn_cast_or_null<TestCastOp>(defOp)) {
432       rewriter.replaceOpWithNewOp<TestReturnOp>(op, packerOp.getOperands());
433       return success();
434     }
435 
436     // Otherwise, fail to match.
437     return failure();
438   }
439 };
440 
441 //===----------------------------------------------------------------------===//
442 // Multi-Level Type-Conversion Rewrite Testing
443 struct TestChangeProducerTypeI32ToF32 : public ConversionPattern {
444   TestChangeProducerTypeI32ToF32(MLIRContext *ctx)
445       : ConversionPattern("test.type_producer", 1, ctx) {}
446   LogicalResult
447   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
448                   ConversionPatternRewriter &rewriter) const final {
449     // If the type is I32, change the type to F32.
450     if (!Type(*op->result_type_begin()).isSignlessInteger(32))
451       return failure();
452     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, rewriter.getF32Type());
453     return success();
454   }
455 };
456 struct TestChangeProducerTypeF32ToF64 : public ConversionPattern {
457   TestChangeProducerTypeF32ToF64(MLIRContext *ctx)
458       : ConversionPattern("test.type_producer", 1, ctx) {}
459   LogicalResult
460   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
461                   ConversionPatternRewriter &rewriter) const final {
462     // If the type is F32, change the type to F64.
463     if (!Type(*op->result_type_begin()).isF32())
464       return rewriter.notifyMatchFailure(op, "expected single f32 operand");
465     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, rewriter.getF64Type());
466     return success();
467   }
468 };
469 struct TestChangeProducerTypeF32ToInvalid : public ConversionPattern {
470   TestChangeProducerTypeF32ToInvalid(MLIRContext *ctx)
471       : ConversionPattern("test.type_producer", 10, ctx) {}
472   LogicalResult
473   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
474                   ConversionPatternRewriter &rewriter) const final {
475     // Always convert to B16, even though it is not a legal type. This tests
476     // that values are unmapped correctly.
477     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, rewriter.getBF16Type());
478     return success();
479   }
480 };
481 struct TestUpdateConsumerType : public ConversionPattern {
482   TestUpdateConsumerType(MLIRContext *ctx)
483       : ConversionPattern("test.type_consumer", 1, ctx) {}
484   LogicalResult
485   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
486                   ConversionPatternRewriter &rewriter) const final {
487     // Verify that the incoming operand has been successfully remapped to F64.
488     if (!operands[0].getType().isF64())
489       return failure();
490     rewriter.replaceOpWithNewOp<TestTypeConsumerOp>(op, operands[0]);
491     return success();
492   }
493 };
494 
495 //===----------------------------------------------------------------------===//
496 // Non-Root Replacement Rewrite Testing
497 /// This pattern generates an invalid operation, but replaces it before the
498 /// pattern is finished. This checks that we don't need to legalize the
499 /// temporary op.
500 struct TestNonRootReplacement : public RewritePattern {
501   TestNonRootReplacement(MLIRContext *ctx)
502       : RewritePattern("test.replace_non_root", 1, ctx) {}
503 
504   LogicalResult matchAndRewrite(Operation *op,
505                                 PatternRewriter &rewriter) const final {
506     auto resultType = *op->result_type_begin();
507     auto illegalOp = rewriter.create<ILLegalOpF>(op->getLoc(), resultType);
508     auto legalOp = rewriter.create<LegalOpB>(op->getLoc(), resultType);
509 
510     rewriter.replaceOp(illegalOp, {legalOp});
511     rewriter.replaceOp(op, {illegalOp});
512     return success();
513   }
514 };
515 
516 //===----------------------------------------------------------------------===//
517 // Recursive Rewrite Testing
518 /// This pattern is applied to the same operation multiple times, but has a
519 /// bounded recursion.
520 struct TestBoundedRecursiveRewrite
521     : public OpRewritePattern<TestRecursiveRewriteOp> {
522   using OpRewritePattern<TestRecursiveRewriteOp>::OpRewritePattern;
523 
524   void initialize() {
525     // The conversion target handles bounding the recursion of this pattern.
526     setHasBoundedRewriteRecursion();
527   }
528 
529   LogicalResult matchAndRewrite(TestRecursiveRewriteOp op,
530                                 PatternRewriter &rewriter) const final {
531     // Decrement the depth of the op in-place.
532     rewriter.updateRootInPlace(op, [&] {
533       op->setAttr("depth", rewriter.getI64IntegerAttr(op.depth() - 1));
534     });
535     return success();
536   }
537 };
538 
539 struct TestNestedOpCreationUndoRewrite
540     : public OpRewritePattern<IllegalOpWithRegionAnchor> {
541   using OpRewritePattern<IllegalOpWithRegionAnchor>::OpRewritePattern;
542 
543   LogicalResult matchAndRewrite(IllegalOpWithRegionAnchor op,
544                                 PatternRewriter &rewriter) const final {
545     // rewriter.replaceOpWithNewOp<IllegalOpWithRegion>(op);
546     rewriter.replaceOpWithNewOp<IllegalOpWithRegion>(op);
547     return success();
548   };
549 };
550 
551 // This pattern matches `test.blackhole` and delete this op and its producer.
552 struct TestReplaceEraseOp : public OpRewritePattern<BlackHoleOp> {
553   using OpRewritePattern<BlackHoleOp>::OpRewritePattern;
554 
555   LogicalResult matchAndRewrite(BlackHoleOp op,
556                                 PatternRewriter &rewriter) const final {
557     Operation *producer = op.getOperand().getDefiningOp();
558     // Always erase the user before the producer, the framework should handle
559     // this correctly.
560     rewriter.eraseOp(op);
561     rewriter.eraseOp(producer);
562     return success();
563   };
564 };
565 
566 // This pattern replaces explicitly illegal op with explicitly legal op,
567 // but in addition creates unregistered operation.
568 struct TestCreateUnregisteredOp : public OpRewritePattern<ILLegalOpG> {
569   using OpRewritePattern<ILLegalOpG>::OpRewritePattern;
570 
571   LogicalResult matchAndRewrite(ILLegalOpG op,
572                                 PatternRewriter &rewriter) const final {
573     IntegerAttr attr = rewriter.getI32IntegerAttr(0);
574     Value val = rewriter.create<ConstantOp>(op->getLoc(), attr);
575     rewriter.replaceOpWithNewOp<LegalOpC>(op, val);
576     return success();
577   };
578 };
579 } // namespace
580 
581 namespace {
582 struct TestTypeConverter : public TypeConverter {
583   using TypeConverter::TypeConverter;
584   TestTypeConverter() {
585     addConversion(convertType);
586     addArgumentMaterialization(materializeCast);
587     addSourceMaterialization(materializeCast);
588 
589     /// Materialize the cast for one-to-one conversion from i64 to f64.
590     const auto materializeOneToOneCast =
591         [](OpBuilder &builder, IntegerType resultType, ValueRange inputs,
592            Location loc) -> Optional<Value> {
593       if (resultType.getWidth() == 42 && inputs.size() == 1)
594         return builder.create<TestCastOp>(loc, resultType, inputs).getResult();
595       return llvm::None;
596     };
597     addArgumentMaterialization(materializeOneToOneCast);
598   }
599 
600   static LogicalResult convertType(Type t, SmallVectorImpl<Type> &results) {
601     // Drop I16 types.
602     if (t.isSignlessInteger(16))
603       return success();
604 
605     // Convert I64 to F64.
606     if (t.isSignlessInteger(64)) {
607       results.push_back(FloatType::getF64(t.getContext()));
608       return success();
609     }
610 
611     // Convert I42 to I43.
612     if (t.isInteger(42)) {
613       results.push_back(IntegerType::get(t.getContext(), 43));
614       return success();
615     }
616 
617     // Split F32 into F16,F16.
618     if (t.isF32()) {
619       results.assign(2, FloatType::getF16(t.getContext()));
620       return success();
621     }
622 
623     // Otherwise, convert the type directly.
624     results.push_back(t);
625     return success();
626   }
627 
628   /// Hook for materializing a conversion. This is necessary because we generate
629   /// 1->N type mappings.
630   static Optional<Value> materializeCast(OpBuilder &builder, Type resultType,
631                                          ValueRange inputs, Location loc) {
632     if (inputs.size() == 1)
633       return inputs[0];
634     return builder.create<TestCastOp>(loc, resultType, inputs).getResult();
635   }
636 };
637 
638 struct TestLegalizePatternDriver
639     : public PassWrapper<TestLegalizePatternDriver, OperationPass<ModuleOp>> {
640   StringRef getArgument() const final { return "test-legalize-patterns"; }
641   StringRef getDescription() const final {
642     return "Run test dialect legalization patterns";
643   }
644   /// The mode of conversion to use with the driver.
645   enum class ConversionMode { Analysis, Full, Partial };
646 
647   TestLegalizePatternDriver(ConversionMode mode) : mode(mode) {}
648 
649   void getDependentDialects(DialectRegistry &registry) const override {
650     registry.insert<StandardOpsDialect>();
651   }
652 
653   void runOnOperation() override {
654     TestTypeConverter converter;
655     mlir::RewritePatternSet patterns(&getContext());
656     populateWithGenerated(patterns);
657     patterns
658         .add<TestRegionRewriteBlockMovement, TestRegionRewriteUndo,
659              TestCreateBlock, TestCreateIllegalBlock, TestUndoBlockArgReplace,
660              TestUndoBlockErase, TestPassthroughInvalidOp, TestSplitReturnType,
661              TestChangeProducerTypeI32ToF32, TestChangeProducerTypeF32ToF64,
662              TestChangeProducerTypeF32ToInvalid, TestUpdateConsumerType,
663              TestNonRootReplacement, TestBoundedRecursiveRewrite,
664              TestNestedOpCreationUndoRewrite, TestReplaceEraseOp,
665              TestCreateUnregisteredOp>(&getContext());
666     patterns.add<TestDropOpSignatureConversion>(&getContext(), converter);
667     mlir::populateFuncOpTypeConversionPattern(patterns, converter);
668     mlir::populateCallOpTypeConversionPattern(patterns, converter);
669 
670     // Define the conversion target used for the test.
671     ConversionTarget target(getContext());
672     target.addLegalOp<ModuleOp>();
673     target.addLegalOp<LegalOpA, LegalOpB, LegalOpC, TestCastOp, TestValidOp,
674                       TerminatorOp>();
675     target
676         .addIllegalOp<ILLegalOpF, TestRegionBuilderOp, TestOpWithRegionFold>();
677     target.addDynamicallyLegalOp<TestReturnOp>([](TestReturnOp op) {
678       // Don't allow F32 operands.
679       return llvm::none_of(op.getOperandTypes(),
680                            [](Type type) { return type.isF32(); });
681     });
682     target.addDynamicallyLegalOp<FuncOp>([&](FuncOp op) {
683       return converter.isSignatureLegal(op.getType()) &&
684              converter.isLegal(&op.getBody());
685     });
686 
687     // TestCreateUnregisteredOp creates `std.constant` operation,
688     // which was not added to target intentionally to test
689     // correct error code from conversion driver.
690     target.addDynamicallyLegalOp<ILLegalOpG>([](ILLegalOpG) { return false; });
691 
692     // Expect the type_producer/type_consumer operations to only operate on f64.
693     target.addDynamicallyLegalOp<TestTypeProducerOp>(
694         [](TestTypeProducerOp op) { return op.getType().isF64(); });
695     target.addDynamicallyLegalOp<TestTypeConsumerOp>([](TestTypeConsumerOp op) {
696       return op.getOperand().getType().isF64();
697     });
698 
699     // Check support for marking certain operations as recursively legal.
700     target.markOpRecursivelyLegal<FuncOp, ModuleOp>([](Operation *op) {
701       return static_cast<bool>(
702           op->getAttrOfType<UnitAttr>("test.recursively_legal"));
703     });
704 
705     // Mark the bound recursion operation as dynamically legal.
706     target.addDynamicallyLegalOp<TestRecursiveRewriteOp>(
707         [](TestRecursiveRewriteOp op) { return op.depth() == 0; });
708 
709     // Handle a partial conversion.
710     if (mode == ConversionMode::Partial) {
711       DenseSet<Operation *> unlegalizedOps;
712       if (failed(applyPartialConversion(
713               getOperation(), target, std::move(patterns), &unlegalizedOps))) {
714         getOperation()->emitRemark() << "applyPartialConversion failed";
715       }
716       // Emit remarks for each legalizable operation.
717       for (auto *op : unlegalizedOps)
718         op->emitRemark() << "op '" << op->getName() << "' is not legalizable";
719       return;
720     }
721 
722     // Handle a full conversion.
723     if (mode == ConversionMode::Full) {
724       // Check support for marking unknown operations as dynamically legal.
725       target.markUnknownOpDynamicallyLegal([](Operation *op) {
726         return (bool)op->getAttrOfType<UnitAttr>("test.dynamically_legal");
727       });
728 
729       if (failed(applyFullConversion(getOperation(), target,
730                                      std::move(patterns)))) {
731         getOperation()->emitRemark() << "applyFullConversion failed";
732       }
733       return;
734     }
735 
736     // Otherwise, handle an analysis conversion.
737     assert(mode == ConversionMode::Analysis);
738 
739     // Analyze the convertible operations.
740     DenseSet<Operation *> legalizedOps;
741     if (failed(applyAnalysisConversion(getOperation(), target,
742                                        std::move(patterns), legalizedOps)))
743       return signalPassFailure();
744 
745     // Emit remarks for each legalizable operation.
746     for (auto *op : legalizedOps)
747       op->emitRemark() << "op '" << op->getName() << "' is legalizable";
748   }
749 
750   /// The mode of conversion to use.
751   ConversionMode mode;
752 };
753 } // end anonymous namespace
754 
755 static llvm::cl::opt<TestLegalizePatternDriver::ConversionMode>
756     legalizerConversionMode(
757         "test-legalize-mode",
758         llvm::cl::desc("The legalization mode to use with the test driver"),
759         llvm::cl::init(TestLegalizePatternDriver::ConversionMode::Partial),
760         llvm::cl::values(
761             clEnumValN(TestLegalizePatternDriver::ConversionMode::Analysis,
762                        "analysis", "Perform an analysis conversion"),
763             clEnumValN(TestLegalizePatternDriver::ConversionMode::Full, "full",
764                        "Perform a full conversion"),
765             clEnumValN(TestLegalizePatternDriver::ConversionMode::Partial,
766                        "partial", "Perform a partial conversion")));
767 
768 //===----------------------------------------------------------------------===//
769 // ConversionPatternRewriter::getRemappedValue testing. This method is used
770 // to get the remapped value of an original value that was replaced using
771 // ConversionPatternRewriter.
772 namespace {
773 /// Converter that replaces a one-result one-operand OneVResOneVOperandOp1 with
774 /// a one-operand two-result OneVResOneVOperandOp1 by replicating its original
775 /// operand twice.
776 ///
777 /// Example:
778 ///   %1 = test.one_variadic_out_one_variadic_in1"(%0)
779 /// is replaced with:
780 ///   %1 = test.one_variadic_out_one_variadic_in1"(%0, %0)
781 struct OneVResOneVOperandOp1Converter
782     : public OpConversionPattern<OneVResOneVOperandOp1> {
783   using OpConversionPattern<OneVResOneVOperandOp1>::OpConversionPattern;
784 
785   LogicalResult
786   matchAndRewrite(OneVResOneVOperandOp1 op, OpAdaptor adaptor,
787                   ConversionPatternRewriter &rewriter) const override {
788     auto origOps = op.getOperands();
789     assert(std::distance(origOps.begin(), origOps.end()) == 1 &&
790            "One operand expected");
791     Value origOp = *origOps.begin();
792     SmallVector<Value, 2> remappedOperands;
793     // Replicate the remapped original operand twice. Note that we don't used
794     // the remapped 'operand' since the goal is testing 'getRemappedValue'.
795     remappedOperands.push_back(rewriter.getRemappedValue(origOp));
796     remappedOperands.push_back(rewriter.getRemappedValue(origOp));
797 
798     rewriter.replaceOpWithNewOp<OneVResOneVOperandOp1>(op, op.getResultTypes(),
799                                                        remappedOperands);
800     return success();
801   }
802 };
803 
804 struct TestRemappedValue
805     : public mlir::PassWrapper<TestRemappedValue, FunctionPass> {
806   StringRef getArgument() const final { return "test-remapped-value"; }
807   StringRef getDescription() const final {
808     return "Test public remapped value mechanism in ConversionPatternRewriter";
809   }
810   void runOnFunction() override {
811     mlir::RewritePatternSet patterns(&getContext());
812     patterns.add<OneVResOneVOperandOp1Converter>(&getContext());
813 
814     mlir::ConversionTarget target(getContext());
815     target.addLegalOp<ModuleOp, FuncOp, TestReturnOp>();
816     // We make OneVResOneVOperandOp1 legal only when it has more that one
817     // operand. This will trigger the conversion that will replace one-operand
818     // OneVResOneVOperandOp1 with two-operand OneVResOneVOperandOp1.
819     target.addDynamicallyLegalOp<OneVResOneVOperandOp1>(
820         [](Operation *op) -> bool {
821           return std::distance(op->operand_begin(), op->operand_end()) > 1;
822         });
823 
824     if (failed(mlir::applyFullConversion(getFunction(), target,
825                                          std::move(patterns)))) {
826       signalPassFailure();
827     }
828   }
829 };
830 } // end anonymous namespace
831 
832 //===----------------------------------------------------------------------===//
833 // Test patterns without a specific root operation kind
834 //===----------------------------------------------------------------------===//
835 
836 namespace {
837 /// This pattern matches and removes any operation in the test dialect.
838 struct RemoveTestDialectOps : public RewritePattern {
839   RemoveTestDialectOps(MLIRContext *context)
840       : RewritePattern(MatchAnyOpTypeTag(), /*benefit=*/1, context) {}
841 
842   LogicalResult matchAndRewrite(Operation *op,
843                                 PatternRewriter &rewriter) const override {
844     if (!isa<TestDialect>(op->getDialect()))
845       return failure();
846     rewriter.eraseOp(op);
847     return success();
848   }
849 };
850 
851 struct TestUnknownRootOpDriver
852     : public mlir::PassWrapper<TestUnknownRootOpDriver, FunctionPass> {
853   StringRef getArgument() const final {
854     return "test-legalize-unknown-root-patterns";
855   }
856   StringRef getDescription() const final {
857     return "Test public remapped value mechanism in ConversionPatternRewriter";
858   }
859   void runOnFunction() override {
860     mlir::RewritePatternSet patterns(&getContext());
861     patterns.add<RemoveTestDialectOps>(&getContext());
862 
863     mlir::ConversionTarget target(getContext());
864     target.addIllegalDialect<TestDialect>();
865     if (failed(
866             applyPartialConversion(getFunction(), target, std::move(patterns))))
867       signalPassFailure();
868   }
869 };
870 } // end anonymous namespace
871 
872 //===----------------------------------------------------------------------===//
873 // Test type conversions
874 //===----------------------------------------------------------------------===//
875 
876 namespace {
877 struct TestTypeConversionProducer
878     : public OpConversionPattern<TestTypeProducerOp> {
879   using OpConversionPattern<TestTypeProducerOp>::OpConversionPattern;
880   LogicalResult
881   matchAndRewrite(TestTypeProducerOp op, OpAdaptor adaptor,
882                   ConversionPatternRewriter &rewriter) const final {
883     Type resultType = op.getType();
884     if (resultType.isa<FloatType>())
885       resultType = rewriter.getF64Type();
886     else if (resultType.isInteger(16))
887       resultType = rewriter.getIntegerType(64);
888     else
889       return failure();
890 
891     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, resultType);
892     return success();
893   }
894 };
895 
896 /// Call signature conversion and then fail the rewrite to trigger the undo
897 /// mechanism.
898 struct TestSignatureConversionUndo
899     : public OpConversionPattern<TestSignatureConversionUndoOp> {
900   using OpConversionPattern<TestSignatureConversionUndoOp>::OpConversionPattern;
901 
902   LogicalResult
903   matchAndRewrite(TestSignatureConversionUndoOp op, OpAdaptor adaptor,
904                   ConversionPatternRewriter &rewriter) const final {
905     (void)rewriter.convertRegionTypes(&op->getRegion(0), *getTypeConverter());
906     return failure();
907   }
908 };
909 
910 /// Just forward the operands to the root op. This is essentially a no-op
911 /// pattern that is used to trigger target materialization.
912 struct TestTypeConsumerForward
913     : public OpConversionPattern<TestTypeConsumerOp> {
914   using OpConversionPattern<TestTypeConsumerOp>::OpConversionPattern;
915 
916   LogicalResult
917   matchAndRewrite(TestTypeConsumerOp op, OpAdaptor adaptor,
918                   ConversionPatternRewriter &rewriter) const final {
919     rewriter.updateRootInPlace(op,
920                                [&] { op->setOperands(adaptor.getOperands()); });
921     return success();
922   }
923 };
924 
925 struct TestTypeConversionAnotherProducer
926     : public OpRewritePattern<TestAnotherTypeProducerOp> {
927   using OpRewritePattern<TestAnotherTypeProducerOp>::OpRewritePattern;
928 
929   LogicalResult matchAndRewrite(TestAnotherTypeProducerOp op,
930                                 PatternRewriter &rewriter) const final {
931     rewriter.replaceOpWithNewOp<TestTypeProducerOp>(op, op.getType());
932     return success();
933   }
934 };
935 
936 struct TestTypeConversionDriver
937     : public PassWrapper<TestTypeConversionDriver, OperationPass<ModuleOp>> {
938   void getDependentDialects(DialectRegistry &registry) const override {
939     registry.insert<TestDialect>();
940   }
941   StringRef getArgument() const final {
942     return "test-legalize-type-conversion";
943   }
944   StringRef getDescription() const final {
945     return "Test various type conversion functionalities in DialectConversion";
946   }
947 
948   void runOnOperation() override {
949     // Initialize the type converter.
950     TypeConverter converter;
951 
952     /// Add the legal set of type conversions.
953     converter.addConversion([](Type type) -> Type {
954       // Treat F64 as legal.
955       if (type.isF64())
956         return type;
957       // Allow converting BF16/F16/F32 to F64.
958       if (type.isBF16() || type.isF16() || type.isF32())
959         return FloatType::getF64(type.getContext());
960       // Otherwise, the type is illegal.
961       return nullptr;
962     });
963     converter.addConversion([](IntegerType type, SmallVectorImpl<Type> &) {
964       // Drop all integer types.
965       return success();
966     });
967 
968     /// Add the legal set of type materializations.
969     converter.addSourceMaterialization([](OpBuilder &builder, Type resultType,
970                                           ValueRange inputs,
971                                           Location loc) -> Value {
972       // Allow casting from F64 back to F32.
973       if (!resultType.isF16() && inputs.size() == 1 &&
974           inputs[0].getType().isF64())
975         return builder.create<TestCastOp>(loc, resultType, inputs).getResult();
976       // Allow producing an i32 or i64 from nothing.
977       if ((resultType.isInteger(32) || resultType.isInteger(64)) &&
978           inputs.empty())
979         return builder.create<TestTypeProducerOp>(loc, resultType);
980       // Allow producing an i64 from an integer.
981       if (resultType.isa<IntegerType>() && inputs.size() == 1 &&
982           inputs[0].getType().isa<IntegerType>())
983         return builder.create<TestCastOp>(loc, resultType, inputs).getResult();
984       // Otherwise, fail.
985       return nullptr;
986     });
987 
988     // Initialize the conversion target.
989     mlir::ConversionTarget target(getContext());
990     target.addDynamicallyLegalOp<TestTypeProducerOp>([](TestTypeProducerOp op) {
991       return op.getType().isF64() || op.getType().isInteger(64);
992     });
993     target.addDynamicallyLegalOp<FuncOp>([&](FuncOp op) {
994       return converter.isSignatureLegal(op.getType()) &&
995              converter.isLegal(&op.getBody());
996     });
997     target.addDynamicallyLegalOp<TestCastOp>([&](TestCastOp op) {
998       // Allow casts from F64 to F32.
999       return (*op.operand_type_begin()).isF64() && op.getType().isF32();
1000     });
1001 
1002     // Initialize the set of rewrite patterns.
1003     RewritePatternSet patterns(&getContext());
1004     patterns.add<TestTypeConsumerForward, TestTypeConversionProducer,
1005                  TestSignatureConversionUndo>(converter, &getContext());
1006     patterns.add<TestTypeConversionAnotherProducer>(&getContext());
1007     mlir::populateFuncOpTypeConversionPattern(patterns, converter);
1008 
1009     if (failed(applyPartialConversion(getOperation(), target,
1010                                       std::move(patterns))))
1011       signalPassFailure();
1012   }
1013 };
1014 } // end anonymous namespace
1015 
1016 //===----------------------------------------------------------------------===//
1017 // Test Block Merging
1018 //===----------------------------------------------------------------------===//
1019 
1020 namespace {
1021 /// A rewriter pattern that tests that blocks can be merged.
1022 struct TestMergeBlock : public OpConversionPattern<TestMergeBlocksOp> {
1023   using OpConversionPattern<TestMergeBlocksOp>::OpConversionPattern;
1024 
1025   LogicalResult
1026   matchAndRewrite(TestMergeBlocksOp op, OpAdaptor adaptor,
1027                   ConversionPatternRewriter &rewriter) const final {
1028     Block &firstBlock = op.body().front();
1029     Operation *branchOp = firstBlock.getTerminator();
1030     Block *secondBlock = &*(std::next(op.body().begin()));
1031     auto succOperands = branchOp->getOperands();
1032     SmallVector<Value, 2> replacements(succOperands);
1033     rewriter.eraseOp(branchOp);
1034     rewriter.mergeBlocks(secondBlock, &firstBlock, replacements);
1035     rewriter.updateRootInPlace(op, [] {});
1036     return success();
1037   }
1038 };
1039 
1040 /// A rewrite pattern to tests the undo mechanism of blocks being merged.
1041 struct TestUndoBlocksMerge : public ConversionPattern {
1042   TestUndoBlocksMerge(MLIRContext *ctx)
1043       : ConversionPattern("test.undo_blocks_merge", /*benefit=*/1, ctx) {}
1044   LogicalResult
1045   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
1046                   ConversionPatternRewriter &rewriter) const final {
1047     Block &firstBlock = op->getRegion(0).front();
1048     Operation *branchOp = firstBlock.getTerminator();
1049     Block *secondBlock = &*(std::next(op->getRegion(0).begin()));
1050     rewriter.setInsertionPointToStart(secondBlock);
1051     rewriter.create<ILLegalOpF>(op->getLoc(), rewriter.getF32Type());
1052     auto succOperands = branchOp->getOperands();
1053     SmallVector<Value, 2> replacements(succOperands);
1054     rewriter.eraseOp(branchOp);
1055     rewriter.mergeBlocks(secondBlock, &firstBlock, replacements);
1056     rewriter.updateRootInPlace(op, [] {});
1057     return success();
1058   }
1059 };
1060 
1061 /// A rewrite mechanism to inline the body of the op into its parent, when both
1062 /// ops can have a single block.
1063 struct TestMergeSingleBlockOps
1064     : public OpConversionPattern<SingleBlockImplicitTerminatorOp> {
1065   using OpConversionPattern<
1066       SingleBlockImplicitTerminatorOp>::OpConversionPattern;
1067 
1068   LogicalResult
1069   matchAndRewrite(SingleBlockImplicitTerminatorOp op, OpAdaptor adaptor,
1070                   ConversionPatternRewriter &rewriter) const final {
1071     SingleBlockImplicitTerminatorOp parentOp =
1072         op->getParentOfType<SingleBlockImplicitTerminatorOp>();
1073     if (!parentOp)
1074       return failure();
1075     Block &innerBlock = op.region().front();
1076     TerminatorOp innerTerminator =
1077         cast<TerminatorOp>(innerBlock.getTerminator());
1078     rewriter.mergeBlockBefore(&innerBlock, op);
1079     rewriter.eraseOp(innerTerminator);
1080     rewriter.eraseOp(op);
1081     rewriter.updateRootInPlace(op, [] {});
1082     return success();
1083   }
1084 };
1085 
1086 struct TestMergeBlocksPatternDriver
1087     : public PassWrapper<TestMergeBlocksPatternDriver,
1088                          OperationPass<ModuleOp>> {
1089   StringRef getArgument() const final { return "test-merge-blocks"; }
1090   StringRef getDescription() const final {
1091     return "Test Merging operation in ConversionPatternRewriter";
1092   }
1093   void runOnOperation() override {
1094     MLIRContext *context = &getContext();
1095     mlir::RewritePatternSet patterns(context);
1096     patterns.add<TestMergeBlock, TestUndoBlocksMerge, TestMergeSingleBlockOps>(
1097         context);
1098     ConversionTarget target(*context);
1099     target.addLegalOp<FuncOp, ModuleOp, TerminatorOp, TestBranchOp,
1100                       TestTypeConsumerOp, TestTypeProducerOp, TestReturnOp>();
1101     target.addIllegalOp<ILLegalOpF>();
1102 
1103     /// Expect the op to have a single block after legalization.
1104     target.addDynamicallyLegalOp<TestMergeBlocksOp>(
1105         [&](TestMergeBlocksOp op) -> bool {
1106           return llvm::hasSingleElement(op.body());
1107         });
1108 
1109     /// Only allow `test.br` within test.merge_blocks op.
1110     target.addDynamicallyLegalOp<TestBranchOp>([&](TestBranchOp op) -> bool {
1111       return op->getParentOfType<TestMergeBlocksOp>();
1112     });
1113 
1114     /// Expect that all nested test.SingleBlockImplicitTerminator ops are
1115     /// inlined.
1116     target.addDynamicallyLegalOp<SingleBlockImplicitTerminatorOp>(
1117         [&](SingleBlockImplicitTerminatorOp op) -> bool {
1118           return !op->getParentOfType<SingleBlockImplicitTerminatorOp>();
1119         });
1120 
1121     DenseSet<Operation *> unlegalizedOps;
1122     (void)applyPartialConversion(getOperation(), target, std::move(patterns),
1123                                  &unlegalizedOps);
1124     for (auto *op : unlegalizedOps)
1125       op->emitRemark() << "op '" << op->getName() << "' is not legalizable";
1126   }
1127 };
1128 } // namespace
1129 
1130 //===----------------------------------------------------------------------===//
1131 // Test Selective Replacement
1132 //===----------------------------------------------------------------------===//
1133 
1134 namespace {
1135 /// A rewrite mechanism to inline the body of the op into its parent, when both
1136 /// ops can have a single block.
1137 struct TestSelectiveOpReplacementPattern : public OpRewritePattern<TestCastOp> {
1138   using OpRewritePattern<TestCastOp>::OpRewritePattern;
1139 
1140   LogicalResult matchAndRewrite(TestCastOp op,
1141                                 PatternRewriter &rewriter) const final {
1142     if (op.getNumOperands() != 2)
1143       return failure();
1144     OperandRange operands = op.getOperands();
1145 
1146     // Replace non-terminator uses with the first operand.
1147     rewriter.replaceOpWithIf(op, operands[0], [](OpOperand &operand) {
1148       return operand.getOwner()->hasTrait<OpTrait::IsTerminator>();
1149     });
1150     // Replace everything else with the second operand if the operation isn't
1151     // dead.
1152     rewriter.replaceOp(op, op.getOperand(1));
1153     return success();
1154   }
1155 };
1156 
1157 struct TestSelectiveReplacementPatternDriver
1158     : public PassWrapper<TestSelectiveReplacementPatternDriver,
1159                          OperationPass<>> {
1160   StringRef getArgument() const final {
1161     return "test-pattern-selective-replacement";
1162   }
1163   StringRef getDescription() const final {
1164     return "Test selective replacement in the PatternRewriter";
1165   }
1166   void runOnOperation() override {
1167     MLIRContext *context = &getContext();
1168     mlir::RewritePatternSet patterns(context);
1169     patterns.add<TestSelectiveOpReplacementPattern>(context);
1170     (void)applyPatternsAndFoldGreedily(getOperation()->getRegions(),
1171                                        std::move(patterns));
1172   }
1173 };
1174 } // namespace
1175 
1176 //===----------------------------------------------------------------------===//
1177 // PassRegistration
1178 //===----------------------------------------------------------------------===//
1179 
1180 namespace mlir {
1181 namespace test {
1182 void registerPatternsTestPass() {
1183   PassRegistration<TestReturnTypeDriver>();
1184 
1185   PassRegistration<TestDerivedAttributeDriver>();
1186 
1187   PassRegistration<TestPatternDriver>();
1188 
1189   PassRegistration<TestLegalizePatternDriver>([] {
1190     return std::make_unique<TestLegalizePatternDriver>(legalizerConversionMode);
1191   });
1192 
1193   PassRegistration<TestRemappedValue>();
1194 
1195   PassRegistration<TestUnknownRootOpDriver>();
1196 
1197   PassRegistration<TestTypeConversionDriver>();
1198 
1199   PassRegistration<TestMergeBlocksPatternDriver>();
1200   PassRegistration<TestSelectiveReplacementPatternDriver>();
1201 }
1202 } // namespace test
1203 } // namespace mlir
1204