75 lines
2.6 KiB
C++
75 lines
2.6 KiB
C++
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//===- TestConstantFold.cpp - Pass to test constant folding ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Pass/Pass.h"
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#include "mlir/Transforms/FoldUtils.h"
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using namespace mlir;
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namespace {
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/// Simple constant folding pass.
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struct TestConstantFold : public PassWrapper<TestConstantFold, OperationPass<>>,
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public RewriterBase::Listener {
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MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestConstantFold)
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StringRef getArgument() const final { return "test-constant-fold"; }
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StringRef getDescription() const final {
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return "Test operation constant folding";
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}
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// All constants in the operation post folding.
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SmallVector<Operation *> existingConstants;
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void foldOperation(Operation *op, OperationFolder &helper);
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void runOnOperation() override;
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void notifyOperationInserted(Operation *op) override {
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existingConstants.push_back(op);
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}
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void notifyOperationRemoved(Operation *op) override {
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auto it = llvm::find(existingConstants, op);
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if (it != existingConstants.end())
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existingConstants.erase(it);
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}
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};
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} // namespace
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void TestConstantFold::foldOperation(Operation *op, OperationFolder &helper) {
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// Attempt to fold the specified operation, including handling unused or
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// duplicated constants.
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(void)helper.tryToFold(op);
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}
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void TestConstantFold::runOnOperation() {
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existingConstants.clear();
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// Collect and fold the operations within the operation.
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SmallVector<Operation *, 8> ops;
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getOperation()->walk<mlir::WalkOrder::PreOrder>([&](Operation *op) { ops.push_back(op); });
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// Fold the constants in reverse so that the last generated constants from
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// folding are at the beginning. This creates somewhat of a linear ordering to
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// the newly generated constants that matches the operation order and improves
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// the readability of test cases.
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OperationFolder helper(&getContext(), /*listener=*/this);
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for (Operation *op : llvm::reverse(ops))
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foldOperation(op, helper);
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// By the time we are done, we may have simplified a bunch of code, leaving
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// around dead constants. Check for them now and remove them.
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for (auto *cst : existingConstants) {
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if (cst->use_empty())
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cst->erase();
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}
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}
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namespace mlir {
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namespace test {
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void registerTestConstantFold() { PassRegistration<TestConstantFold>(); }
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} // namespace test
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} // namespace mlir
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