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//===- LoopLikeInterface.cpp - Loop-like operations in MLIR ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "mlir/Interfaces/LoopLikeInterface.h"
#include "mlir/IR/FunctionInterfaces.h"
#include "llvm/ADT/DenseSet.h"
using namespace mlir;
/// Include the definitions of the loop-like interfaces.
#include "mlir/Interfaces/LoopLikeInterface.cpp.inc"
bool LoopLikeOpInterface::blockIsInLoop(Block *block) {
Operation *parent = block->getParentOp();
// The block could be inside a loop-like operation
if (isa<LoopLikeOpInterface>(parent) ||
parent->getParentOfType<LoopLikeOpInterface>())
return true;
// This block might be nested inside another block, which is in a loop
if (!isa<FunctionOpInterface>(parent))
if (mlir::Block *parentBlock = parent->getBlock())
if (blockIsInLoop(parentBlock))
return true;
// Or the block could be inside a control flow graph loop:
// A block is in a control flow graph loop if it can reach itself in a graph
// traversal
DenseSet<Block *> visited;
SmallVector<Block *> stack;
stack.push_back(block);
while (!stack.empty()) {
Block *current = stack.pop_back_val();
auto [it, inserted] = visited.insert(current);
if (!inserted) {
// loop detected
if (current == block)
return true;
continue;
}
stack.reserve(stack.size() + current->getNumSuccessors());
for (Block *successor : current->getSuccessors())
stack.push_back(successor);
}
return false;
}
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