308571074c
This is an artifact from merging MLIR into LLVM, the file headers are now aligned with the rest of the project.
69 lines
2.5 KiB
C++
69 lines
2.5 KiB
C++
//===- 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/Dialect/AffineOps/AffineOps.h"
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#include "mlir/Dialect/StandardOps/Ops.h"
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#include "mlir/IR/Builders.h"
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#include "mlir/IR/Function.h"
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#include "mlir/Pass/Pass.h"
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#include "mlir/Transforms/FoldUtils.h"
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#include "mlir/Transforms/Passes.h"
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#include "mlir/Transforms/Utils.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 FunctionPass<TestConstantFold> {
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// All constants in the function post folding.
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SmallVector<Operation *, 8> existingConstants;
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void foldOperation(Operation *op, OperationFolder &helper);
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void runOnFunction() override;
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};
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} // end anonymous namespace
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void TestConstantFold::foldOperation(Operation *op, OperationFolder &helper) {
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auto processGeneratedConstants = [this](Operation *op) {
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existingConstants.push_back(op);
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};
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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, processGeneratedConstants);
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}
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// For now, we do a simple top-down pass over a function folding constants. We
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// don't handle conditional control flow, block arguments, folding conditional
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// branches, or anything else fancy.
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void TestConstantFold::runOnFunction() {
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existingConstants.clear();
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// Collect and fold the operations within the function.
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SmallVector<Operation *, 8> ops;
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getFunction().walk([&](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());
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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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static PassRegistration<TestConstantFold>
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pass("test-constant-fold", "Test operation constant folding");
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