308571074c
This is an artifact from merging MLIR into LLVM, the file headers are now aligned with the rest of the project.
109 lines
3.7 KiB
C++
109 lines
3.7 KiB
C++
//===- SimplifyAffineStructures.cpp ---------------------------------------===//
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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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//
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// This file implements a pass to simplify affine structures.
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Analysis/AffineStructures.h"
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#include "mlir/IR/IntegerSet.h"
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#include "mlir/Pass/Pass.h"
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#include "mlir/Transforms/Passes.h"
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#include "mlir/Transforms/Utils.h"
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#define DEBUG_TYPE "simplify-affine-structure"
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using namespace mlir;
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namespace {
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/// Simplifies affine maps and sets appearing in the operations of the Function.
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/// This part is mainly to test the simplifyAffineExpr method. In addition,
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/// all memrefs with non-trivial layout maps are converted to ones with trivial
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/// identity layout ones.
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struct SimplifyAffineStructures
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: public FunctionPass<SimplifyAffineStructures> {
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void runOnFunction() override;
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/// Utility to simplify an affine attribute and update its entry in the parent
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/// operation if necessary.
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template <typename AttributeT>
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void simplifyAndUpdateAttribute(Operation *op, Identifier name,
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AttributeT attr) {
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auto &simplified = simplifiedAttributes[attr];
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if (simplified == attr)
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return;
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// This is a newly encountered attribute.
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if (!simplified) {
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// Try to simplify the value of the attribute.
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auto value = attr.getValue();
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auto simplifiedValue = simplify(value);
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if (simplifiedValue == value) {
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simplified = attr;
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return;
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}
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simplified = AttributeT::get(simplifiedValue);
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}
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// Simplification was successful, so update the attribute.
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op->setAttr(name, simplified);
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}
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/// Performs basic integer set simplifications. Checks if it's empty, and
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/// replaces it with the canonical empty set if it is.
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IntegerSet simplify(IntegerSet set) {
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FlatAffineConstraints fac(set);
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if (fac.isEmpty())
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return IntegerSet::getEmptySet(set.getNumDims(), set.getNumSymbols(),
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&getContext());
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return set;
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}
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/// Performs basic affine map simplifications.
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AffineMap simplify(AffineMap map) {
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MutableAffineMap mMap(map);
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mMap.simplify();
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return mMap.getAffineMap();
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}
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DenseMap<Attribute, Attribute> simplifiedAttributes;
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};
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} // end anonymous namespace
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std::unique_ptr<OpPassBase<FuncOp>> mlir::createSimplifyAffineStructuresPass() {
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return std::make_unique<SimplifyAffineStructures>();
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}
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void SimplifyAffineStructures::runOnFunction() {
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auto func = getFunction();
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simplifiedAttributes.clear();
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func.walk([&](Operation *opInst) {
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for (auto attr : opInst->getAttrs()) {
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if (auto mapAttr = attr.second.dyn_cast<AffineMapAttr>())
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simplifyAndUpdateAttribute(opInst, attr.first, mapAttr);
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else if (auto setAttr = attr.second.dyn_cast<IntegerSetAttr>())
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simplifyAndUpdateAttribute(opInst, attr.first, setAttr);
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}
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});
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// Turn memrefs' non-identity layouts maps into ones with identity. Collect
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// alloc ops first and then process since normalizeMemRef replaces/erases ops
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// during memref rewriting.
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SmallVector<AllocOp, 4> allocOps;
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func.walk([&](AllocOp op) { allocOps.push_back(op); });
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for (auto allocOp : allocOps) {
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normalizeMemRef(allocOp);
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}
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}
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static PassRegistration<SimplifyAffineStructures>
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pass("simplify-affine-structures",
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"Simplify affine expressions in maps/sets and normalize memrefs");
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