1 //===- Operation.cpp - Operation support code -----------------------------===//
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 "mlir/IR/Operation.h"
10 #include "mlir/IR/BlockAndValueMapping.h"
11 #include "mlir/IR/BuiltinTypes.h"
12 #include "mlir/IR/Dialect.h"
13 #include "mlir/IR/OpImplementation.h"
14 #include "mlir/IR/PatternMatch.h"
15 #include "mlir/IR/TypeUtilities.h"
16 #include "mlir/Interfaces/FoldInterfaces.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include <numeric>
19 
20 using namespace mlir;
21 
22 //===----------------------------------------------------------------------===//
23 // Operation
24 //===----------------------------------------------------------------------===//
25 
26 /// Create a new Operation with the specific fields.
27 Operation *Operation::create(Location location, OperationName name,
28                              TypeRange resultTypes, ValueRange operands,
29                              ArrayRef<NamedAttribute> attributes,
30                              BlockRange successors, unsigned numRegions) {
31   return create(location, name, resultTypes, operands,
32                 DictionaryAttr::get(location.getContext(), attributes),
33                 successors, numRegions);
34 }
35 
36 /// Create a new Operation from operation state.
37 Operation *Operation::create(const OperationState &state) {
38   return create(state.location, state.name, state.types, state.operands,
39                 state.attributes.getDictionary(state.getContext()),
40                 state.successors, state.regions);
41 }
42 
43 /// Create a new Operation with the specific fields.
44 Operation *Operation::create(Location location, OperationName name,
45                              TypeRange resultTypes, ValueRange operands,
46                              DictionaryAttr attributes, BlockRange successors,
47                              RegionRange regions) {
48   unsigned numRegions = regions.size();
49   Operation *op = create(location, name, resultTypes, operands, attributes,
50                          successors, numRegions);
51   for (unsigned i = 0; i < numRegions; ++i)
52     if (regions[i])
53       op->getRegion(i).takeBody(*regions[i]);
54   return op;
55 }
56 
57 /// Overload of create that takes an existing DictionaryAttr to avoid
58 /// unnecessarily uniquing a list of attributes.
59 Operation *Operation::create(Location location, OperationName name,
60                              TypeRange resultTypes, ValueRange operands,
61                              DictionaryAttr attributes, BlockRange successors,
62                              unsigned numRegions) {
63   assert(llvm::all_of(resultTypes, [](Type t) { return t; }) &&
64          "unexpected null result type");
65 
66   // We only need to allocate additional memory for a subset of results.
67   unsigned numTrailingResults = OpResult::getNumTrailing(resultTypes.size());
68   unsigned numInlineResults = OpResult::getNumInline(resultTypes.size());
69   unsigned numSuccessors = successors.size();
70   unsigned numOperands = operands.size();
71   unsigned numResults = resultTypes.size();
72 
73   // If the operation is known to have no operands, don't allocate an operand
74   // storage.
75   bool needsOperandStorage =
76       operands.empty() ? !name.hasTrait<OpTrait::ZeroOperands>() : true;
77 
78   // Compute the byte size for the operation and the operand storage. This takes
79   // into account the size of the operation, its trailing objects, and its
80   // prefixed objects.
81   size_t byteSize =
82       totalSizeToAlloc<detail::OperandStorage, BlockOperand, Region, OpOperand>(
83           needsOperandStorage ? 1 : 0, numSuccessors, numRegions, numOperands);
84   size_t prefixByteSize = llvm::alignTo(
85       Operation::prefixAllocSize(numTrailingResults, numInlineResults),
86       alignof(Operation));
87   char *mallocMem = reinterpret_cast<char *>(malloc(byteSize + prefixByteSize));
88   void *rawMem = mallocMem + prefixByteSize;
89 
90   // Create the new Operation.
91   Operation *op =
92       ::new (rawMem) Operation(location, name, numResults, numSuccessors,
93                                numRegions, attributes, needsOperandStorage);
94 
95   assert((numSuccessors == 0 || op->mightHaveTrait<OpTrait::IsTerminator>()) &&
96          "unexpected successors in a non-terminator operation");
97 
98   // Initialize the results.
99   auto resultTypeIt = resultTypes.begin();
100   for (unsigned i = 0; i < numInlineResults; ++i, ++resultTypeIt)
101     new (op->getInlineOpResult(i)) detail::InlineOpResult(*resultTypeIt, i);
102   for (unsigned i = 0; i < numTrailingResults; ++i, ++resultTypeIt) {
103     new (op->getOutOfLineOpResult(i))
104         detail::OutOfLineOpResult(*resultTypeIt, i);
105   }
106 
107   // Initialize the regions.
108   for (unsigned i = 0; i != numRegions; ++i)
109     new (&op->getRegion(i)) Region(op);
110 
111   // Initialize the operands.
112   if (needsOperandStorage) {
113     new (&op->getOperandStorage()) detail::OperandStorage(
114         op, op->getTrailingObjects<OpOperand>(), operands);
115   }
116 
117   // Initialize the successors.
118   auto blockOperands = op->getBlockOperands();
119   for (unsigned i = 0; i != numSuccessors; ++i)
120     new (&blockOperands[i]) BlockOperand(op, successors[i]);
121 
122   return op;
123 }
124 
125 Operation::Operation(Location location, OperationName name, unsigned numResults,
126                      unsigned numSuccessors, unsigned numRegions,
127                      DictionaryAttr attributes, bool hasOperandStorage)
128     : location(location), numResults(numResults), numSuccs(numSuccessors),
129       numRegions(numRegions), hasOperandStorage(hasOperandStorage), name(name),
130       attrs(attributes) {
131   assert(attributes && "unexpected null attribute dictionary");
132 #ifndef NDEBUG
133   if (!getDialect() && !getContext()->allowsUnregisteredDialects())
134     llvm::report_fatal_error(
135         name.getStringRef() +
136         " created with unregistered dialect. If this is intended, please call "
137         "allowUnregisteredDialects() on the MLIRContext, or use "
138         "-allow-unregistered-dialect with the MLIR tool used.");
139 #endif
140 }
141 
142 // Operations are deleted through the destroy() member because they are
143 // allocated via malloc.
144 Operation::~Operation() {
145   assert(block == nullptr && "operation destroyed but still in a block");
146 #ifndef NDEBUG
147   if (!use_empty()) {
148     {
149       InFlightDiagnostic diag =
150           emitOpError("operation destroyed but still has uses");
151       for (Operation *user : getUsers())
152         diag.attachNote(user->getLoc()) << "- use: " << *user << "\n";
153     }
154     llvm::report_fatal_error("operation destroyed but still has uses");
155   }
156 #endif
157   // Explicitly run the destructors for the operands.
158   if (hasOperandStorage)
159     getOperandStorage().~OperandStorage();
160 
161   // Explicitly run the destructors for the successors.
162   for (auto &successor : getBlockOperands())
163     successor.~BlockOperand();
164 
165   // Explicitly destroy the regions.
166   for (auto &region : getRegions())
167     region.~Region();
168 }
169 
170 /// Destroy this operation or one of its subclasses.
171 void Operation::destroy() {
172   // Operations may have additional prefixed allocation, which needs to be
173   // accounted for here when computing the address to free.
174   char *rawMem = reinterpret_cast<char *>(this) -
175                  llvm::alignTo(prefixAllocSize(), alignof(Operation));
176   this->~Operation();
177   free(rawMem);
178 }
179 
180 /// Return true if this operation is a proper ancestor of the `other`
181 /// operation.
182 bool Operation::isProperAncestor(Operation *other) {
183   while ((other = other->getParentOp()))
184     if (this == other)
185       return true;
186   return false;
187 }
188 
189 /// Replace any uses of 'from' with 'to' within this operation.
190 void Operation::replaceUsesOfWith(Value from, Value to) {
191   if (from == to)
192     return;
193   for (auto &operand : getOpOperands())
194     if (operand.get() == from)
195       operand.set(to);
196 }
197 
198 /// Replace the current operands of this operation with the ones provided in
199 /// 'operands'.
200 void Operation::setOperands(ValueRange operands) {
201   if (LLVM_LIKELY(hasOperandStorage))
202     return getOperandStorage().setOperands(this, operands);
203   assert(operands.empty() && "setting operands without an operand storage");
204 }
205 
206 /// Replace the operands beginning at 'start' and ending at 'start' + 'length'
207 /// with the ones provided in 'operands'. 'operands' may be smaller or larger
208 /// than the range pointed to by 'start'+'length'.
209 void Operation::setOperands(unsigned start, unsigned length,
210                             ValueRange operands) {
211   assert((start + length) <= getNumOperands() &&
212          "invalid operand range specified");
213   if (LLVM_LIKELY(hasOperandStorage))
214     return getOperandStorage().setOperands(this, start, length, operands);
215   assert(operands.empty() && "setting operands without an operand storage");
216 }
217 
218 /// Insert the given operands into the operand list at the given 'index'.
219 void Operation::insertOperands(unsigned index, ValueRange operands) {
220   if (LLVM_LIKELY(hasOperandStorage))
221     return setOperands(index, /*length=*/0, operands);
222   assert(operands.empty() && "inserting operands without an operand storage");
223 }
224 
225 //===----------------------------------------------------------------------===//
226 // Diagnostics
227 //===----------------------------------------------------------------------===//
228 
229 /// Emit an error about fatal conditions with this operation, reporting up to
230 /// any diagnostic handlers that may be listening.
231 InFlightDiagnostic Operation::emitError(const Twine &message) {
232   InFlightDiagnostic diag = mlir::emitError(getLoc(), message);
233   if (getContext()->shouldPrintOpOnDiagnostic()) {
234     diag.attachNote(getLoc())
235         .append("see current operation: ")
236         .appendOp(*this, OpPrintingFlags().printGenericOpForm());
237   }
238   return diag;
239 }
240 
241 /// Emit a warning about this operation, reporting up to any diagnostic
242 /// handlers that may be listening.
243 InFlightDiagnostic Operation::emitWarning(const Twine &message) {
244   InFlightDiagnostic diag = mlir::emitWarning(getLoc(), message);
245   if (getContext()->shouldPrintOpOnDiagnostic())
246     diag.attachNote(getLoc()) << "see current operation: " << *this;
247   return diag;
248 }
249 
250 /// Emit a remark about this operation, reporting up to any diagnostic
251 /// handlers that may be listening.
252 InFlightDiagnostic Operation::emitRemark(const Twine &message) {
253   InFlightDiagnostic diag = mlir::emitRemark(getLoc(), message);
254   if (getContext()->shouldPrintOpOnDiagnostic())
255     diag.attachNote(getLoc()) << "see current operation: " << *this;
256   return diag;
257 }
258 
259 //===----------------------------------------------------------------------===//
260 // Operation Ordering
261 //===----------------------------------------------------------------------===//
262 
263 constexpr unsigned Operation::kInvalidOrderIdx;
264 constexpr unsigned Operation::kOrderStride;
265 
266 /// Given an operation 'other' that is within the same parent block, return
267 /// whether the current operation is before 'other' in the operation list
268 /// of the parent block.
269 /// Note: This function has an average complexity of O(1), but worst case may
270 /// take O(N) where N is the number of operations within the parent block.
271 bool Operation::isBeforeInBlock(Operation *other) {
272   assert(block && "Operations without parent blocks have no order.");
273   assert(other && other->block == block &&
274          "Expected other operation to have the same parent block.");
275   // If the order of the block is already invalid, directly recompute the
276   // parent.
277   if (!block->isOpOrderValid()) {
278     block->recomputeOpOrder();
279   } else {
280     // Update the order either operation if necessary.
281     updateOrderIfNecessary();
282     other->updateOrderIfNecessary();
283   }
284 
285   return orderIndex < other->orderIndex;
286 }
287 
288 /// Update the order index of this operation of this operation if necessary,
289 /// potentially recomputing the order of the parent block.
290 void Operation::updateOrderIfNecessary() {
291   assert(block && "expected valid parent");
292 
293   // If the order is valid for this operation there is nothing to do.
294   if (hasValidOrder())
295     return;
296   Operation *blockFront = &block->front();
297   Operation *blockBack = &block->back();
298 
299   // This method is expected to only be invoked on blocks with more than one
300   // operation.
301   assert(blockFront != blockBack && "expected more than one operation");
302 
303   // If the operation is at the end of the block.
304   if (this == blockBack) {
305     Operation *prevNode = getPrevNode();
306     if (!prevNode->hasValidOrder())
307       return block->recomputeOpOrder();
308 
309     // Add the stride to the previous operation.
310     orderIndex = prevNode->orderIndex + kOrderStride;
311     return;
312   }
313 
314   // If this is the first operation try to use the next operation to compute the
315   // ordering.
316   if (this == blockFront) {
317     Operation *nextNode = getNextNode();
318     if (!nextNode->hasValidOrder())
319       return block->recomputeOpOrder();
320     // There is no order to give this operation.
321     if (nextNode->orderIndex == 0)
322       return block->recomputeOpOrder();
323 
324     // If we can't use the stride, just take the middle value left. This is safe
325     // because we know there is at least one valid index to assign to.
326     if (nextNode->orderIndex <= kOrderStride)
327       orderIndex = (nextNode->orderIndex / 2);
328     else
329       orderIndex = kOrderStride;
330     return;
331   }
332 
333   // Otherwise, this operation is between two others. Place this operation in
334   // the middle of the previous and next if possible.
335   Operation *prevNode = getPrevNode(), *nextNode = getNextNode();
336   if (!prevNode->hasValidOrder() || !nextNode->hasValidOrder())
337     return block->recomputeOpOrder();
338   unsigned prevOrder = prevNode->orderIndex, nextOrder = nextNode->orderIndex;
339 
340   // Check to see if there is a valid order between the two.
341   if (prevOrder + 1 == nextOrder)
342     return block->recomputeOpOrder();
343   orderIndex = prevOrder + ((nextOrder - prevOrder) / 2);
344 }
345 
346 //===----------------------------------------------------------------------===//
347 // ilist_traits for Operation
348 //===----------------------------------------------------------------------===//
349 
350 auto llvm::ilist_detail::SpecificNodeAccess<
351     typename llvm::ilist_detail::compute_node_options<
352         ::mlir::Operation>::type>::getNodePtr(pointer N) -> node_type * {
353   return NodeAccess::getNodePtr<OptionsT>(N);
354 }
355 
356 auto llvm::ilist_detail::SpecificNodeAccess<
357     typename llvm::ilist_detail::compute_node_options<
358         ::mlir::Operation>::type>::getNodePtr(const_pointer N)
359     -> const node_type * {
360   return NodeAccess::getNodePtr<OptionsT>(N);
361 }
362 
363 auto llvm::ilist_detail::SpecificNodeAccess<
364     typename llvm::ilist_detail::compute_node_options<
365         ::mlir::Operation>::type>::getValuePtr(node_type *N) -> pointer {
366   return NodeAccess::getValuePtr<OptionsT>(N);
367 }
368 
369 auto llvm::ilist_detail::SpecificNodeAccess<
370     typename llvm::ilist_detail::compute_node_options<
371         ::mlir::Operation>::type>::getValuePtr(const node_type *N)
372     -> const_pointer {
373   return NodeAccess::getValuePtr<OptionsT>(N);
374 }
375 
376 void llvm::ilist_traits<::mlir::Operation>::deleteNode(Operation *op) {
377   op->destroy();
378 }
379 
380 Block *llvm::ilist_traits<::mlir::Operation>::getContainingBlock() {
381   size_t Offset(size_t(&((Block *)nullptr->*Block::getSublistAccess(nullptr))));
382   iplist<Operation> *Anchor(static_cast<iplist<Operation> *>(this));
383   return reinterpret_cast<Block *>(reinterpret_cast<char *>(Anchor) - Offset);
384 }
385 
386 /// This is a trait method invoked when an operation is added to a block.  We
387 /// keep the block pointer up to date.
388 void llvm::ilist_traits<::mlir::Operation>::addNodeToList(Operation *op) {
389   assert(!op->getBlock() && "already in an operation block!");
390   op->block = getContainingBlock();
391 
392   // Invalidate the order on the operation.
393   op->orderIndex = Operation::kInvalidOrderIdx;
394 }
395 
396 /// This is a trait method invoked when an operation is removed from a block.
397 /// We keep the block pointer up to date.
398 void llvm::ilist_traits<::mlir::Operation>::removeNodeFromList(Operation *op) {
399   assert(op->block && "not already in an operation block!");
400   op->block = nullptr;
401 }
402 
403 /// This is a trait method invoked when an operation is moved from one block
404 /// to another.  We keep the block pointer up to date.
405 void llvm::ilist_traits<::mlir::Operation>::transferNodesFromList(
406     ilist_traits<Operation> &otherList, op_iterator first, op_iterator last) {
407   Block *curParent = getContainingBlock();
408 
409   // Invalidate the ordering of the parent block.
410   curParent->invalidateOpOrder();
411 
412   // If we are transferring operations within the same block, the block
413   // pointer doesn't need to be updated.
414   if (curParent == otherList.getContainingBlock())
415     return;
416 
417   // Update the 'block' member of each operation.
418   for (; first != last; ++first)
419     first->block = curParent;
420 }
421 
422 /// Remove this operation (and its descendants) from its Block and delete
423 /// all of them.
424 void Operation::erase() {
425   if (auto *parent = getBlock())
426     parent->getOperations().erase(this);
427   else
428     destroy();
429 }
430 
431 /// Remove the operation from its parent block, but don't delete it.
432 void Operation::remove() {
433   if (Block *parent = getBlock())
434     parent->getOperations().remove(this);
435 }
436 
437 /// Unlink this operation from its current block and insert it right before
438 /// `existingOp` which may be in the same or another block in the same
439 /// function.
440 void Operation::moveBefore(Operation *existingOp) {
441   moveBefore(existingOp->getBlock(), existingOp->getIterator());
442 }
443 
444 /// Unlink this operation from its current basic block and insert it right
445 /// before `iterator` in the specified basic block.
446 void Operation::moveBefore(Block *block,
447                            llvm::iplist<Operation>::iterator iterator) {
448   block->getOperations().splice(iterator, getBlock()->getOperations(),
449                                 getIterator());
450 }
451 
452 /// Unlink this operation from its current block and insert it right after
453 /// `existingOp` which may be in the same or another block in the same function.
454 void Operation::moveAfter(Operation *existingOp) {
455   moveAfter(existingOp->getBlock(), existingOp->getIterator());
456 }
457 
458 /// Unlink this operation from its current block and insert it right after
459 /// `iterator` in the specified block.
460 void Operation::moveAfter(Block *block,
461                           llvm::iplist<Operation>::iterator iterator) {
462   assert(iterator != block->end() && "cannot move after end of block");
463   moveBefore(block, std::next(iterator));
464 }
465 
466 /// This drops all operand uses from this operation, which is an essential
467 /// step in breaking cyclic dependences between references when they are to
468 /// be deleted.
469 void Operation::dropAllReferences() {
470   for (auto &op : getOpOperands())
471     op.drop();
472 
473   for (auto &region : getRegions())
474     region.dropAllReferences();
475 
476   for (auto &dest : getBlockOperands())
477     dest.drop();
478 }
479 
480 /// This drops all uses of any values defined by this operation or its nested
481 /// regions, wherever they are located.
482 void Operation::dropAllDefinedValueUses() {
483   dropAllUses();
484 
485   for (auto &region : getRegions())
486     for (auto &block : region)
487       block.dropAllDefinedValueUses();
488 }
489 
490 void Operation::setSuccessor(Block *block, unsigned index) {
491   assert(index < getNumSuccessors());
492   getBlockOperands()[index].set(block);
493 }
494 
495 /// Attempt to fold this operation using the Op's registered foldHook.
496 LogicalResult Operation::fold(ArrayRef<Attribute> operands,
497                               SmallVectorImpl<OpFoldResult> &results) {
498   // If we have a registered operation definition matching this one, use it to
499   // try to constant fold the operation.
500   Optional<RegisteredOperationName> info = getRegisteredInfo();
501   if (info && succeeded(info->foldHook(this, operands, results)))
502     return success();
503 
504   // Otherwise, fall back on the dialect hook to handle it.
505   Dialect *dialect = getDialect();
506   if (!dialect)
507     return failure();
508 
509   auto *interface = dialect->getRegisteredInterface<DialectFoldInterface>();
510   if (!interface)
511     return failure();
512 
513   return interface->fold(this, operands, results);
514 }
515 
516 /// Emit an error with the op name prefixed, like "'dim' op " which is
517 /// convenient for verifiers.
518 InFlightDiagnostic Operation::emitOpError(const Twine &message) {
519   return emitError() << "'" << getName() << "' op " << message;
520 }
521 
522 //===----------------------------------------------------------------------===//
523 // Operation Cloning
524 //===----------------------------------------------------------------------===//
525 
526 /// Create a deep copy of this operation but keep the operation regions empty.
527 /// Operands are remapped using `mapper` (if present), and `mapper` is updated
528 /// to contain the results.
529 Operation *Operation::cloneWithoutRegions(BlockAndValueMapping &mapper) {
530   SmallVector<Value, 8> operands;
531   SmallVector<Block *, 2> successors;
532 
533   // Remap the operands.
534   operands.reserve(getNumOperands());
535   for (auto opValue : getOperands())
536     operands.push_back(mapper.lookupOrDefault(opValue));
537 
538   // Remap the successors.
539   successors.reserve(getNumSuccessors());
540   for (Block *successor : getSuccessors())
541     successors.push_back(mapper.lookupOrDefault(successor));
542 
543   // Create the new operation.
544   auto *newOp = create(getLoc(), getName(), getResultTypes(), operands, attrs,
545                        successors, getNumRegions());
546 
547   // Remember the mapping of any results.
548   for (unsigned i = 0, e = getNumResults(); i != e; ++i)
549     mapper.map(getResult(i), newOp->getResult(i));
550 
551   return newOp;
552 }
553 
554 Operation *Operation::cloneWithoutRegions() {
555   BlockAndValueMapping mapper;
556   return cloneWithoutRegions(mapper);
557 }
558 
559 /// Create a deep copy of this operation, remapping any operands that use
560 /// values outside of the operation using the map that is provided (leaving
561 /// them alone if no entry is present).  Replaces references to cloned
562 /// sub-operations to the corresponding operation that is copied, and adds
563 /// those mappings to the map.
564 Operation *Operation::clone(BlockAndValueMapping &mapper) {
565   auto *newOp = cloneWithoutRegions(mapper);
566 
567   // Clone the regions.
568   for (unsigned i = 0; i != numRegions; ++i)
569     getRegion(i).cloneInto(&newOp->getRegion(i), mapper);
570 
571   return newOp;
572 }
573 
574 Operation *Operation::clone() {
575   BlockAndValueMapping mapper;
576   return clone(mapper);
577 }
578 
579 //===----------------------------------------------------------------------===//
580 // OpState trait class.
581 //===----------------------------------------------------------------------===//
582 
583 // The fallback for the parser is to reject the custom assembly form.
584 ParseResult OpState::parse(OpAsmParser &parser, OperationState &result) {
585   return parser.emitError(parser.getNameLoc(), "has no custom assembly form");
586 }
587 
588 // The fallback for the printer is to print in the generic assembly form.
589 void OpState::print(Operation *op, OpAsmPrinter &p) { p.printGenericOp(op); }
590 // The fallback for the printer is to print in the generic assembly form.
591 void OpState::printOpName(Operation *op, OpAsmPrinter &p,
592                           StringRef defaultDialect) {
593   StringRef name = op->getName().getStringRef();
594   if (name.startswith((defaultDialect + ".").str()))
595     name = name.drop_front(defaultDialect.size() + 1);
596   // TODO: remove this special case (and update test/IR/parser.mlir)
597   else if ((defaultDialect.empty() || defaultDialect == "builtin") &&
598            name.startswith("std."))
599     name = name.drop_front(4);
600   p.getStream() << name;
601 }
602 
603 /// Emit an error about fatal conditions with this operation, reporting up to
604 /// any diagnostic handlers that may be listening.
605 InFlightDiagnostic OpState::emitError(const Twine &message) {
606   return getOperation()->emitError(message);
607 }
608 
609 /// Emit an error with the op name prefixed, like "'dim' op " which is
610 /// convenient for verifiers.
611 InFlightDiagnostic OpState::emitOpError(const Twine &message) {
612   return getOperation()->emitOpError(message);
613 }
614 
615 /// Emit a warning about this operation, reporting up to any diagnostic
616 /// handlers that may be listening.
617 InFlightDiagnostic OpState::emitWarning(const Twine &message) {
618   return getOperation()->emitWarning(message);
619 }
620 
621 /// Emit a remark about this operation, reporting up to any diagnostic
622 /// handlers that may be listening.
623 InFlightDiagnostic OpState::emitRemark(const Twine &message) {
624   return getOperation()->emitRemark(message);
625 }
626 
627 //===----------------------------------------------------------------------===//
628 // Op Trait implementations
629 //===----------------------------------------------------------------------===//
630 
631 OpFoldResult OpTrait::impl::foldIdempotent(Operation *op) {
632   if (op->getNumOperands() == 1) {
633     auto *argumentOp = op->getOperand(0).getDefiningOp();
634     if (argumentOp && op->getName() == argumentOp->getName()) {
635       // Replace the outer operation output with the inner operation.
636       return op->getOperand(0);
637     }
638   } else if (op->getOperand(0) == op->getOperand(1)) {
639     return op->getOperand(0);
640   }
641 
642   return {};
643 }
644 
645 OpFoldResult OpTrait::impl::foldInvolution(Operation *op) {
646   auto *argumentOp = op->getOperand(0).getDefiningOp();
647   if (argumentOp && op->getName() == argumentOp->getName()) {
648     // Replace the outer involutions output with inner's input.
649     return argumentOp->getOperand(0);
650   }
651 
652   return {};
653 }
654 
655 LogicalResult OpTrait::impl::verifyZeroOperands(Operation *op) {
656   if (op->getNumOperands() != 0)
657     return op->emitOpError() << "requires zero operands";
658   return success();
659 }
660 
661 LogicalResult OpTrait::impl::verifyOneOperand(Operation *op) {
662   if (op->getNumOperands() != 1)
663     return op->emitOpError() << "requires a single operand";
664   return success();
665 }
666 
667 LogicalResult OpTrait::impl::verifyNOperands(Operation *op,
668                                              unsigned numOperands) {
669   if (op->getNumOperands() != numOperands) {
670     return op->emitOpError() << "expected " << numOperands
671                              << " operands, but found " << op->getNumOperands();
672   }
673   return success();
674 }
675 
676 LogicalResult OpTrait::impl::verifyAtLeastNOperands(Operation *op,
677                                                     unsigned numOperands) {
678   if (op->getNumOperands() < numOperands)
679     return op->emitOpError()
680            << "expected " << numOperands << " or more operands, but found "
681            << op->getNumOperands();
682   return success();
683 }
684 
685 /// If this is a vector type, or a tensor type, return the scalar element type
686 /// that it is built around, otherwise return the type unmodified.
687 static Type getTensorOrVectorElementType(Type type) {
688   if (auto vec = type.dyn_cast<VectorType>())
689     return vec.getElementType();
690 
691   // Look through tensor<vector<...>> to find the underlying element type.
692   if (auto tensor = type.dyn_cast<TensorType>())
693     return getTensorOrVectorElementType(tensor.getElementType());
694   return type;
695 }
696 
697 LogicalResult OpTrait::impl::verifyIsIdempotent(Operation *op) {
698   // FIXME: Add back check for no side effects on operation.
699   // Currently adding it would cause the shared library build
700   // to fail since there would be a dependency of IR on SideEffectInterfaces
701   // which is cyclical.
702   return success();
703 }
704 
705 LogicalResult OpTrait::impl::verifyIsInvolution(Operation *op) {
706   // FIXME: Add back check for no side effects on operation.
707   // Currently adding it would cause the shared library build
708   // to fail since there would be a dependency of IR on SideEffectInterfaces
709   // which is cyclical.
710   return success();
711 }
712 
713 LogicalResult
714 OpTrait::impl::verifyOperandsAreSignlessIntegerLike(Operation *op) {
715   for (auto opType : op->getOperandTypes()) {
716     auto type = getTensorOrVectorElementType(opType);
717     if (!type.isSignlessIntOrIndex())
718       return op->emitOpError() << "requires an integer or index type";
719   }
720   return success();
721 }
722 
723 LogicalResult OpTrait::impl::verifyOperandsAreFloatLike(Operation *op) {
724   for (auto opType : op->getOperandTypes()) {
725     auto type = getTensorOrVectorElementType(opType);
726     if (!type.isa<FloatType>())
727       return op->emitOpError("requires a float type");
728   }
729   return success();
730 }
731 
732 LogicalResult OpTrait::impl::verifySameTypeOperands(Operation *op) {
733   // Zero or one operand always have the "same" type.
734   unsigned nOperands = op->getNumOperands();
735   if (nOperands < 2)
736     return success();
737 
738   auto type = op->getOperand(0).getType();
739   for (auto opType : llvm::drop_begin(op->getOperandTypes(), 1))
740     if (opType != type)
741       return op->emitOpError() << "requires all operands to have the same type";
742   return success();
743 }
744 
745 LogicalResult OpTrait::impl::verifyZeroRegion(Operation *op) {
746   if (op->getNumRegions() != 0)
747     return op->emitOpError() << "requires zero regions";
748   return success();
749 }
750 
751 LogicalResult OpTrait::impl::verifyOneRegion(Operation *op) {
752   if (op->getNumRegions() != 1)
753     return op->emitOpError() << "requires one region";
754   return success();
755 }
756 
757 LogicalResult OpTrait::impl::verifyNRegions(Operation *op,
758                                             unsigned numRegions) {
759   if (op->getNumRegions() != numRegions)
760     return op->emitOpError() << "expected " << numRegions << " regions";
761   return success();
762 }
763 
764 LogicalResult OpTrait::impl::verifyAtLeastNRegions(Operation *op,
765                                                    unsigned numRegions) {
766   if (op->getNumRegions() < numRegions)
767     return op->emitOpError() << "expected " << numRegions << " or more regions";
768   return success();
769 }
770 
771 LogicalResult OpTrait::impl::verifyZeroResult(Operation *op) {
772   if (op->getNumResults() != 0)
773     return op->emitOpError() << "requires zero results";
774   return success();
775 }
776 
777 LogicalResult OpTrait::impl::verifyOneResult(Operation *op) {
778   if (op->getNumResults() != 1)
779     return op->emitOpError() << "requires one result";
780   return success();
781 }
782 
783 LogicalResult OpTrait::impl::verifyNResults(Operation *op,
784                                             unsigned numOperands) {
785   if (op->getNumResults() != numOperands)
786     return op->emitOpError() << "expected " << numOperands << " results";
787   return success();
788 }
789 
790 LogicalResult OpTrait::impl::verifyAtLeastNResults(Operation *op,
791                                                    unsigned numOperands) {
792   if (op->getNumResults() < numOperands)
793     return op->emitOpError()
794            << "expected " << numOperands << " or more results";
795   return success();
796 }
797 
798 LogicalResult OpTrait::impl::verifySameOperandsShape(Operation *op) {
799   if (failed(verifyAtLeastNOperands(op, 1)))
800     return failure();
801 
802   if (failed(verifyCompatibleShapes(op->getOperandTypes())))
803     return op->emitOpError() << "requires the same shape for all operands";
804 
805   return success();
806 }
807 
808 LogicalResult OpTrait::impl::verifySameOperandsAndResultShape(Operation *op) {
809   if (failed(verifyAtLeastNOperands(op, 1)) ||
810       failed(verifyAtLeastNResults(op, 1)))
811     return failure();
812 
813   SmallVector<Type, 8> types(op->getOperandTypes());
814   types.append(llvm::to_vector<4>(op->getResultTypes()));
815 
816   if (failed(verifyCompatibleShapes(types)))
817     return op->emitOpError()
818            << "requires the same shape for all operands and results";
819 
820   return success();
821 }
822 
823 LogicalResult OpTrait::impl::verifySameOperandsElementType(Operation *op) {
824   if (failed(verifyAtLeastNOperands(op, 1)))
825     return failure();
826   auto elementType = getElementTypeOrSelf(op->getOperand(0));
827 
828   for (auto operand : llvm::drop_begin(op->getOperands(), 1)) {
829     if (getElementTypeOrSelf(operand) != elementType)
830       return op->emitOpError("requires the same element type for all operands");
831   }
832 
833   return success();
834 }
835 
836 LogicalResult
837 OpTrait::impl::verifySameOperandsAndResultElementType(Operation *op) {
838   if (failed(verifyAtLeastNOperands(op, 1)) ||
839       failed(verifyAtLeastNResults(op, 1)))
840     return failure();
841 
842   auto elementType = getElementTypeOrSelf(op->getResult(0));
843 
844   // Verify result element type matches first result's element type.
845   for (auto result : llvm::drop_begin(op->getResults(), 1)) {
846     if (getElementTypeOrSelf(result) != elementType)
847       return op->emitOpError(
848           "requires the same element type for all operands and results");
849   }
850 
851   // Verify operand's element type matches first result's element type.
852   for (auto operand : op->getOperands()) {
853     if (getElementTypeOrSelf(operand) != elementType)
854       return op->emitOpError(
855           "requires the same element type for all operands and results");
856   }
857 
858   return success();
859 }
860 
861 LogicalResult OpTrait::impl::verifySameOperandsAndResultType(Operation *op) {
862   if (failed(verifyAtLeastNOperands(op, 1)) ||
863       failed(verifyAtLeastNResults(op, 1)))
864     return failure();
865 
866   auto type = op->getResult(0).getType();
867   auto elementType = getElementTypeOrSelf(type);
868   for (auto resultType : llvm::drop_begin(op->getResultTypes())) {
869     if (getElementTypeOrSelf(resultType) != elementType ||
870         failed(verifyCompatibleShape(resultType, type)))
871       return op->emitOpError()
872              << "requires the same type for all operands and results";
873   }
874   for (auto opType : op->getOperandTypes()) {
875     if (getElementTypeOrSelf(opType) != elementType ||
876         failed(verifyCompatibleShape(opType, type)))
877       return op->emitOpError()
878              << "requires the same type for all operands and results";
879   }
880   return success();
881 }
882 
883 LogicalResult OpTrait::impl::verifyIsTerminator(Operation *op) {
884   Block *block = op->getBlock();
885   // Verify that the operation is at the end of the respective parent block.
886   if (!block || &block->back() != op)
887     return op->emitOpError("must be the last operation in the parent block");
888   return success();
889 }
890 
891 static LogicalResult verifyTerminatorSuccessors(Operation *op) {
892   auto *parent = op->getParentRegion();
893 
894   // Verify that the operands lines up with the BB arguments in the successor.
895   for (Block *succ : op->getSuccessors())
896     if (succ->getParent() != parent)
897       return op->emitError("reference to block defined in another region");
898   return success();
899 }
900 
901 LogicalResult OpTrait::impl::verifyZeroSuccessor(Operation *op) {
902   if (op->getNumSuccessors() != 0) {
903     return op->emitOpError("requires 0 successors but found ")
904            << op->getNumSuccessors();
905   }
906   return success();
907 }
908 
909 LogicalResult OpTrait::impl::verifyOneSuccessor(Operation *op) {
910   if (op->getNumSuccessors() != 1) {
911     return op->emitOpError("requires 1 successor but found ")
912            << op->getNumSuccessors();
913   }
914   return verifyTerminatorSuccessors(op);
915 }
916 LogicalResult OpTrait::impl::verifyNSuccessors(Operation *op,
917                                                unsigned numSuccessors) {
918   if (op->getNumSuccessors() != numSuccessors) {
919     return op->emitOpError("requires ")
920            << numSuccessors << " successors but found "
921            << op->getNumSuccessors();
922   }
923   return verifyTerminatorSuccessors(op);
924 }
925 LogicalResult OpTrait::impl::verifyAtLeastNSuccessors(Operation *op,
926                                                       unsigned numSuccessors) {
927   if (op->getNumSuccessors() < numSuccessors) {
928     return op->emitOpError("requires at least ")
929            << numSuccessors << " successors but found "
930            << op->getNumSuccessors();
931   }
932   return verifyTerminatorSuccessors(op);
933 }
934 
935 LogicalResult OpTrait::impl::verifyResultsAreBoolLike(Operation *op) {
936   for (auto resultType : op->getResultTypes()) {
937     auto elementType = getTensorOrVectorElementType(resultType);
938     bool isBoolType = elementType.isInteger(1);
939     if (!isBoolType)
940       return op->emitOpError() << "requires a bool result type";
941   }
942 
943   return success();
944 }
945 
946 LogicalResult OpTrait::impl::verifyResultsAreFloatLike(Operation *op) {
947   for (auto resultType : op->getResultTypes())
948     if (!getTensorOrVectorElementType(resultType).isa<FloatType>())
949       return op->emitOpError() << "requires a floating point type";
950 
951   return success();
952 }
953 
954 LogicalResult
955 OpTrait::impl::verifyResultsAreSignlessIntegerLike(Operation *op) {
956   for (auto resultType : op->getResultTypes())
957     if (!getTensorOrVectorElementType(resultType).isSignlessIntOrIndex())
958       return op->emitOpError() << "requires an integer or index type";
959   return success();
960 }
961 
962 LogicalResult OpTrait::impl::verifyValueSizeAttr(Operation *op,
963                                                  StringRef attrName,
964                                                  StringRef valueGroupName,
965                                                  size_t expectedCount) {
966   auto sizeAttr = op->getAttrOfType<DenseIntElementsAttr>(attrName);
967   if (!sizeAttr)
968     return op->emitOpError("requires 1D i32 elements attribute '")
969            << attrName << "'";
970 
971   auto sizeAttrType = sizeAttr.getType();
972   if (sizeAttrType.getRank() != 1 ||
973       !sizeAttrType.getElementType().isInteger(32))
974     return op->emitOpError("requires 1D i32 elements attribute '")
975            << attrName << "'";
976 
977   if (llvm::any_of(sizeAttr.getValues<APInt>(), [](const APInt &element) {
978         return !element.isNonNegative();
979       }))
980     return op->emitOpError("'")
981            << attrName << "' attribute cannot have negative elements";
982 
983   size_t totalCount = std::accumulate(
984       sizeAttr.begin(), sizeAttr.end(), 0,
985       [](unsigned all, APInt one) { return all + one.getZExtValue(); });
986 
987   if (totalCount != expectedCount)
988     return op->emitOpError()
989            << valueGroupName << " count (" << expectedCount
990            << ") does not match with the total size (" << totalCount
991            << ") specified in attribute '" << attrName << "'";
992   return success();
993 }
994 
995 LogicalResult OpTrait::impl::verifyOperandSizeAttr(Operation *op,
996                                                    StringRef attrName) {
997   return verifyValueSizeAttr(op, attrName, "operand", op->getNumOperands());
998 }
999 
1000 LogicalResult OpTrait::impl::verifyResultSizeAttr(Operation *op,
1001                                                   StringRef attrName) {
1002   return verifyValueSizeAttr(op, attrName, "result", op->getNumResults());
1003 }
1004 
1005 LogicalResult OpTrait::impl::verifyNoRegionArguments(Operation *op) {
1006   for (Region &region : op->getRegions()) {
1007     if (region.empty())
1008       continue;
1009 
1010     if (region.getNumArguments() != 0) {
1011       if (op->getNumRegions() > 1)
1012         return op->emitOpError("region #")
1013                << region.getRegionNumber() << " should have no arguments";
1014       else
1015         return op->emitOpError("region should have no arguments");
1016     }
1017   }
1018   return success();
1019 }
1020 
1021 LogicalResult OpTrait::impl::verifyElementwise(Operation *op) {
1022   auto isMappableType = [](Type type) {
1023     return type.isa<VectorType, TensorType>();
1024   };
1025   auto resultMappableTypes = llvm::to_vector<1>(
1026       llvm::make_filter_range(op->getResultTypes(), isMappableType));
1027   auto operandMappableTypes = llvm::to_vector<2>(
1028       llvm::make_filter_range(op->getOperandTypes(), isMappableType));
1029 
1030   // If the op only has scalar operand/result types, then we have nothing to
1031   // check.
1032   if (resultMappableTypes.empty() && operandMappableTypes.empty())
1033     return success();
1034 
1035   if (!resultMappableTypes.empty() && operandMappableTypes.empty())
1036     return op->emitOpError("if a result is non-scalar, then at least one "
1037                            "operand must be non-scalar");
1038 
1039   assert(!operandMappableTypes.empty());
1040 
1041   if (resultMappableTypes.empty())
1042     return op->emitOpError("if an operand is non-scalar, then there must be at "
1043                            "least one non-scalar result");
1044 
1045   if (resultMappableTypes.size() != op->getNumResults())
1046     return op->emitOpError(
1047         "if an operand is non-scalar, then all results must be non-scalar");
1048 
1049   SmallVector<Type, 4> types = llvm::to_vector<2>(
1050       llvm::concat<Type>(operandMappableTypes, resultMappableTypes));
1051   TypeID expectedBaseTy = types.front().getTypeID();
1052   if (!llvm::all_of(types,
1053                     [&](Type t) { return t.getTypeID() == expectedBaseTy; }) ||
1054       failed(verifyCompatibleShapes(types))) {
1055     return op->emitOpError() << "all non-scalar operands/results must have the "
1056                                 "same shape and base type";
1057   }
1058 
1059   return success();
1060 }
1061 
1062 /// Check for any values used by operations regions attached to the
1063 /// specified "IsIsolatedFromAbove" operation defined outside of it.
1064 LogicalResult OpTrait::impl::verifyIsIsolatedFromAbove(Operation *isolatedOp) {
1065   assert(isolatedOp->hasTrait<OpTrait::IsIsolatedFromAbove>() &&
1066          "Intended to check IsolatedFromAbove ops");
1067 
1068   // List of regions to analyze.  Each region is processed independently, with
1069   // respect to the common `limit` region, so we can look at them in any order.
1070   // Therefore, use a simple vector and push/pop back the current region.
1071   SmallVector<Region *, 8> pendingRegions;
1072   for (auto &region : isolatedOp->getRegions()) {
1073     pendingRegions.push_back(&region);
1074 
1075     // Traverse all operations in the region.
1076     while (!pendingRegions.empty()) {
1077       for (Operation &op : pendingRegions.pop_back_val()->getOps()) {
1078         for (Value operand : op.getOperands()) {
1079           // operand should be non-null here if the IR is well-formed. But
1080           // we don't assert here as this function is called from the verifier
1081           // and so could be called on invalid IR.
1082           if (!operand)
1083             return op.emitOpError("operation's operand is null");
1084 
1085           // Check that any value that is used by an operation is defined in the
1086           // same region as either an operation result.
1087           auto *operandRegion = operand.getParentRegion();
1088           if (!region.isAncestor(operandRegion)) {
1089             return op.emitOpError("using value defined outside the region")
1090                        .attachNote(isolatedOp->getLoc())
1091                    << "required by region isolation constraints";
1092           }
1093         }
1094 
1095         // Schedule any regions in the operation for further checking.  Don't
1096         // recurse into other IsolatedFromAbove ops, because they will check
1097         // themselves.
1098         if (op.getNumRegions() &&
1099             !op.hasTrait<OpTrait::IsIsolatedFromAbove>()) {
1100           for (Region &subRegion : op.getRegions())
1101             pendingRegions.push_back(&subRegion);
1102         }
1103       }
1104     }
1105   }
1106 
1107   return success();
1108 }
1109 
1110 bool OpTrait::hasElementwiseMappableTraits(Operation *op) {
1111   return op->hasTrait<Elementwise>() && op->hasTrait<Scalarizable>() &&
1112          op->hasTrait<Vectorizable>() && op->hasTrait<Tensorizable>();
1113 }
1114 
1115 //===----------------------------------------------------------------------===//
1116 // BinaryOp implementation
1117 //===----------------------------------------------------------------------===//
1118 
1119 // These functions are out-of-line implementations of the methods in BinaryOp,
1120 // which avoids them being template instantiated/duplicated.
1121 
1122 void impl::buildBinaryOp(OpBuilder &builder, OperationState &result, Value lhs,
1123                          Value rhs) {
1124   assert(lhs.getType() == rhs.getType());
1125   result.addOperands({lhs, rhs});
1126   result.types.push_back(lhs.getType());
1127 }
1128 
1129 ParseResult impl::parseOneResultSameOperandTypeOp(OpAsmParser &parser,
1130                                                   OperationState &result) {
1131   SmallVector<OpAsmParser::OperandType, 2> ops;
1132   Type type;
1133   // If the operand list is in-between parentheses, then we have a generic form.
1134   // (see the fallback in `printOneResultOp`).
1135   llvm::SMLoc loc = parser.getCurrentLocation();
1136   if (!parser.parseOptionalLParen()) {
1137     if (parser.parseOperandList(ops) || parser.parseRParen() ||
1138         parser.parseOptionalAttrDict(result.attributes) ||
1139         parser.parseColon() || parser.parseType(type))
1140       return failure();
1141     auto fnType = type.dyn_cast<FunctionType>();
1142     if (!fnType) {
1143       parser.emitError(loc, "expected function type");
1144       return failure();
1145     }
1146     if (parser.resolveOperands(ops, fnType.getInputs(), loc, result.operands))
1147       return failure();
1148     result.addTypes(fnType.getResults());
1149     return success();
1150   }
1151   return failure(parser.parseOperandList(ops) ||
1152                  parser.parseOptionalAttrDict(result.attributes) ||
1153                  parser.parseColonType(type) ||
1154                  parser.resolveOperands(ops, type, result.operands) ||
1155                  parser.addTypeToList(type, result.types));
1156 }
1157 
1158 void impl::printOneResultOp(Operation *op, OpAsmPrinter &p) {
1159   assert(op->getNumResults() == 1 && "op should have one result");
1160 
1161   // If not all the operand and result types are the same, just use the
1162   // generic assembly form to avoid omitting information in printing.
1163   auto resultType = op->getResult(0).getType();
1164   if (llvm::any_of(op->getOperandTypes(),
1165                    [&](Type type) { return type != resultType; })) {
1166     p.printGenericOp(op, /*printOpName=*/false);
1167     return;
1168   }
1169 
1170   p << ' ';
1171   p.printOperands(op->getOperands());
1172   p.printOptionalAttrDict(op->getAttrs());
1173   // Now we can output only one type for all operands and the result.
1174   p << " : " << resultType;
1175 }
1176 
1177 //===----------------------------------------------------------------------===//
1178 // CastOp implementation
1179 //===----------------------------------------------------------------------===//
1180 
1181 /// Attempt to fold the given cast operation.
1182 LogicalResult
1183 impl::foldCastInterfaceOp(Operation *op, ArrayRef<Attribute> attrOperands,
1184                           SmallVectorImpl<OpFoldResult> &foldResults) {
1185   OperandRange operands = op->getOperands();
1186   if (operands.empty())
1187     return failure();
1188   ResultRange results = op->getResults();
1189 
1190   // Check for the case where the input and output types match 1-1.
1191   if (operands.getTypes() == results.getTypes()) {
1192     foldResults.append(operands.begin(), operands.end());
1193     return success();
1194   }
1195 
1196   return failure();
1197 }
1198 
1199 /// Attempt to verify the given cast operation.
1200 LogicalResult impl::verifyCastInterfaceOp(
1201     Operation *op, function_ref<bool(TypeRange, TypeRange)> areCastCompatible) {
1202   auto resultTypes = op->getResultTypes();
1203   if (llvm::empty(resultTypes))
1204     return op->emitOpError()
1205            << "expected at least one result for cast operation";
1206 
1207   auto operandTypes = op->getOperandTypes();
1208   if (!areCastCompatible(operandTypes, resultTypes)) {
1209     InFlightDiagnostic diag = op->emitOpError("operand type");
1210     if (llvm::empty(operandTypes))
1211       diag << "s []";
1212     else if (llvm::size(operandTypes) == 1)
1213       diag << " " << *operandTypes.begin();
1214     else
1215       diag << "s " << operandTypes;
1216     return diag << " and result type" << (resultTypes.size() == 1 ? " " : "s ")
1217                 << resultTypes << " are cast incompatible";
1218   }
1219 
1220   return success();
1221 }
1222 
1223 void impl::buildCastOp(OpBuilder &builder, OperationState &result, Value source,
1224                        Type destType) {
1225   result.addOperands(source);
1226   result.addTypes(destType);
1227 }
1228 
1229 ParseResult impl::parseCastOp(OpAsmParser &parser, OperationState &result) {
1230   OpAsmParser::OperandType srcInfo;
1231   Type srcType, dstType;
1232   return failure(parser.parseOperand(srcInfo) ||
1233                  parser.parseOptionalAttrDict(result.attributes) ||
1234                  parser.parseColonType(srcType) ||
1235                  parser.resolveOperand(srcInfo, srcType, result.operands) ||
1236                  parser.parseKeywordType("to", dstType) ||
1237                  parser.addTypeToList(dstType, result.types));
1238 }
1239 
1240 void impl::printCastOp(Operation *op, OpAsmPrinter &p) {
1241   p << ' ' << op->getOperand(0);
1242   p.printOptionalAttrDict(op->getAttrs());
1243   p << " : " << op->getOperand(0).getType() << " to "
1244     << op->getResult(0).getType();
1245 }
1246 
1247 Value impl::foldCastOp(Operation *op) {
1248   // Identity cast
1249   if (op->getOperand(0).getType() == op->getResult(0).getType())
1250     return op->getOperand(0);
1251   return nullptr;
1252 }
1253 
1254 LogicalResult
1255 impl::verifyCastOp(Operation *op,
1256                    function_ref<bool(Type, Type)> areCastCompatible) {
1257   auto opType = op->getOperand(0).getType();
1258   auto resType = op->getResult(0).getType();
1259   if (!areCastCompatible(opType, resType))
1260     return op->emitError("operand type ")
1261            << opType << " and result type " << resType
1262            << " are cast incompatible";
1263 
1264   return success();
1265 }
1266 
1267 //===----------------------------------------------------------------------===//
1268 // Misc. utils
1269 //===----------------------------------------------------------------------===//
1270 
1271 /// Insert an operation, generated by `buildTerminatorOp`, at the end of the
1272 /// region's only block if it does not have a terminator already. If the region
1273 /// is empty, insert a new block first. `buildTerminatorOp` should return the
1274 /// terminator operation to insert.
1275 void impl::ensureRegionTerminator(
1276     Region &region, OpBuilder &builder, Location loc,
1277     function_ref<Operation *(OpBuilder &, Location)> buildTerminatorOp) {
1278   OpBuilder::InsertionGuard guard(builder);
1279   if (region.empty())
1280     builder.createBlock(&region);
1281 
1282   Block &block = region.back();
1283   if (!block.empty() && block.back().hasTrait<OpTrait::IsTerminator>())
1284     return;
1285 
1286   builder.setInsertionPointToEnd(&block);
1287   builder.insert(buildTerminatorOp(builder, loc));
1288 }
1289 
1290 /// Create a simple OpBuilder and forward to the OpBuilder version of this
1291 /// function.
1292 void impl::ensureRegionTerminator(
1293     Region &region, Builder &builder, Location loc,
1294     function_ref<Operation *(OpBuilder &, Location)> buildTerminatorOp) {
1295   OpBuilder opBuilder(builder.getContext());
1296   ensureRegionTerminator(region, opBuilder, loc, buildTerminatorOp);
1297 }
1298