csullivan commented on code in PR #12972: URL: https://github.com/apache/tvm/pull/12972#discussion_r992844279
########## src/arith/conjunctive_normal_form.cc: ########## @@ -0,0 +1,415 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/*! + * \file tvm/arith/conjunctive_normal_form.cc + */ + +#include "conjunctive_normal_form.h" + +#include <tvm/arith/analyzer.h> +#include <tvm/tir/expr.h> + +#include <optional> +#include <unordered_map> +#include <unordered_set> +#include <utility> +#include <vector> + +#include "pattern_match.h" +#include "rewrite_simplify.h" + +namespace tvm { +namespace arith { + +namespace { +/* \brief A utility for simplifying expressions using conjunctive/disjuctive normal forms */ +class AndOfOrs { + public: + /*! \brief Construct the simplifier + * + * Convert a PrimExpr to the internal representation. + * + * \param expr The PrimExpr to be simplified. + */ + explicit AndOfOrs(const PrimExpr& expr); + + /*! \brief Convert internal representation to PrimExpr */ + PrimExpr AsPrimExpr() const; + + /*! \brief Simplify the internal representation */ + void Simplify(Analyzer* analyzer); + + private: + /*! \brief Internal utility, simplify within each group of expressions + * + * For each pair of values within a chunk, attempt to simplify them into + * a single expression. + * + * For example, + * before = (a == 5) && ((b < 10) || (b > 10)) + * after = (a == 5) && ((b != 10) || false) + */ + void SimplifyWithinChunks(Analyzer* analyzer); + + /*! \brief Internal utility, simplify across groups of expressions + * + * For each pair of chunks, if the two chunks differ by only a single + * term, attempt to simplify those differing terms. + * + * For example, + * before = ((a == 5) || (b <= 10)) && ((a == 5) || (b >= 10)) + * after = ((a == 5) || (b == 10)) && ((a == 5) || true) + */ + void SimplifyAcrossChunks(Analyzer* analyzer); + + /*! \brief Remove instances of true/false from internal representation + * + * To avoid invalidating iterators, `SimplifyWithinChunks` and + * `SimplifyAcrossChunks` may replace keys, but may not remove keys from + * the internal representation. For example, `(a < 5) && (a < 10)` + * would be simplified to `(a < 5) && true`. The `Cleanup` function + * removes these leftover instances of true/false. + */ + void Cleanup(); + + /*! \brief Internal utility function used to convert to internal form */ + static void VisitAndExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback); + /*! \brief Internal utility function used to convert to internal form */ + static void VisitOrExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback); + + /* \brief Type-safe wrapper class that represents an PrimExpr + * + * Because integer indices are used frequently through this class, + * maintaining a separation between integer indices used to access + * specific elements of the internal representation, and unique + * identifiers used to represent expressions PrimExpr, is useful. + */ + enum class Key : size_t {}; + + /*! \brief Convert a PrimExpr to a Key */ + Key GetKey(const PrimExpr& expr); + + /*! \brief Convert a Key to a PrimExpr */ + PrimExpr GetExpr(Key key) const; + + /*! \brief Attempt to simplify (a && b) + * + * If successful, will overwrite the parameters `a` and `b` with the + * simplified form. + */ + void TrySimplifyOr(Key* a, Key* b, Analyzer* analyzer); + + /*! \brief Attempt to simplify (a || b) + * + * If successful, will overwrite the parameters `a` and `b` with the + * simplified form. + */ + void TrySimplifyAnd(Key* a, Key* b, Analyzer* analyzer); + + /*! \brief The internal representation + * + * `chunks[i][j]` is the j-th expression in the i-th OR-group. + */ + std::vector<std::vector<Key>> chunks; + + /*! \brief Mapping from internal Key to PrimExpr */ + std::unordered_map<Key, PrimExpr, StructuralHash, StructuralEqual> key_to_expr; + + /*! \brief Mapping from PrimExpr to internal Key */ + std::unordered_map<PrimExpr, Key, StructuralHash, StructuralEqual> expr_to_key; + + /*! \brief Cached key representing tir::Bool(true) */ + Key key_true; + + /*! \brief Cached key representing tir::Bool(false) */ + Key key_false; +}; + +AndOfOrs::AndOfOrs(const PrimExpr& expr) + : key_true(GetKey(Bool(true))), key_false(GetKey(Bool(false))) { + VisitAndExpressions(expr, [&](const PrimExpr& outer_expr) { + std::vector<Key> or_components; + VisitOrExpressions(outer_expr, [&](const PrimExpr& inner_expr) { + Key key = GetKey(inner_expr); + bool is_duplicate = std::any_of(or_components.begin(), or_components.end(), + [&](Key prev) { return prev == key; }); + if (!is_duplicate) { + or_components.push_back(key); + } + }); + + bool is_permutation = + std::any_of(chunks.begin(), chunks.end(), [&](const std::vector<Key>& prev_components) { + return or_components.size() == prev_components.size() && + std::is_permutation(prev_components.begin(), prev_components.end(), + or_components.begin()); + }); + if (!is_permutation) { + chunks.push_back(std::move(or_components)); + } + }); +} + +void AndOfOrs::VisitAndExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback) { + PVar<PrimExpr> x, y, z; + if ((x && y).Match(expr)) { + VisitAndExpressions(x.Eval(), callback); + VisitAndExpressions(y.Eval(), callback); + } else if ((x || y).Match(expr)) { + VisitAndExpressions(x.Eval(), [&](const PrimExpr& x_part) { + VisitAndExpressions(y.Eval(), [&](const PrimExpr& y_part) { callback(x_part || y_part); }); + }); + } else { + callback(expr); + } +} + +void AndOfOrs::VisitOrExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback) { + PVar<PrimExpr> x, y, z; + if ((x || y).Match(expr)) { + VisitOrExpressions(x.Eval(), callback); + VisitOrExpressions(y.Eval(), callback); + } else if ((x && y).Match(expr)) { + VisitOrExpressions(x.Eval(), [&](const PrimExpr& x_part) { + VisitOrExpressions(y.Eval(), [&](const PrimExpr& y_part) { callback(x_part && y_part); }); + }); + } else { + callback(expr); + } +} + +AndOfOrs::Key AndOfOrs::GetKey(const PrimExpr& expr) { + auto it = expr_to_key.find(expr); + if (it != expr_to_key.end()) { + return it->second; + } + + Key key{expr_to_key.size()}; + expr_to_key[expr] = key; + key_to_expr[key] = expr; + return key; +} + +PrimExpr AndOfOrs::GetExpr(AndOfOrs::Key key) const { + auto it = key_to_expr.find(key); + ICHECK(it != key_to_expr.end()); + return it->second; +} + +PrimExpr AndOfOrs::AsPrimExpr() const { + PrimExpr expr = Bool(true); + for (const auto& chunk : chunks) { + PrimExpr chunk_expr = Bool(false); + for (Key j : chunk) { + chunk_expr = chunk_expr || GetExpr(j); + } + expr = expr && chunk_expr; + } + return expr; +} + +void AndOfOrs::TrySimplifyOr(Key* a_ptr, Key* b_ptr, Analyzer* analyzer) { + Key& a = *a_ptr; + Key& b = *b_ptr; + PrimExpr joint = GetExpr(a) || GetExpr(b); + PrimExpr simplified = analyzer->Simplify(joint); + if (!ExprDeepEqual()(simplified, joint)) { + if (auto* simplified_or = simplified.as<OrNode>()) { + a = GetKey(simplified_or->a); + b = GetKey(simplified_or->b); + } else { + a = key_false; + b = GetKey(simplified); + } + } +} + +void AndOfOrs::TrySimplifyAnd(Key* a_ptr, Key* b_ptr, Analyzer* analyzer) { + Key& a = *a_ptr; + Key& b = *b_ptr; + PrimExpr joint = GetExpr(a) && GetExpr(b); + PrimExpr simplified = analyzer->Simplify(joint); + if (!ExprDeepEqual()(simplified, joint)) { + if (auto* simplified_and = simplified.as<AndNode>()) { + a = GetKey(simplified_and->a); + b = GetKey(simplified_and->b); + } else { + a = key_true; + b = GetKey(simplified); + } + } +} + +void AndOfOrs::Simplify(Analyzer* analyzer) { + SimplifyWithinChunks(analyzer); + Cleanup(); + SimplifyAcrossChunks(analyzer); + Cleanup(); +} + +void AndOfOrs::SimplifyWithinChunks(Analyzer* analyzer) { + for (auto& chunk : chunks) { + for (size_t expr_i = 0; expr_i < chunk.size(); expr_i++) { + for (size_t expr_j = expr_i + 1; expr_j < chunk.size(); expr_j++) { + Key& key_i = chunk[expr_i]; + Key& key_j = chunk[expr_j]; + + TrySimplifyOr(&key_i, &key_j, analyzer); + } + } + } +} + +void AndOfOrs::SimplifyAcrossChunks(Analyzer* analyzer) { + for (size_t i_and = 0; i_and < chunks.size(); i_and++) { + for (size_t j_and = i_and + 1; j_and < chunks.size(); j_and++) { + auto& i_chunk = chunks[i_and]; + auto& j_chunk = chunks[j_and]; + + if (i_chunk.size() == 1 && j_chunk.size() == 1) { + auto& key_i = i_chunk[0]; + auto& key_j = j_chunk[0]; + TrySimplifyAnd(&key_i, &key_j, analyzer); + continue; + } + std::unordered_set<Key> j_set(j_chunk.begin(), j_chunk.end()); + + std::optional<size_t> i_distinct_index; + for (size_t i = 0; i < i_chunk.size(); i++) { + if (!j_set.count(i_chunk[i])) { + i_distinct_index = i; + break; + } + } + + if (!i_distinct_index.has_value()) { + // I = (i_0 || i_1 || ... || i_N) + // J = (i_0 || i_1 || ... || i_N || j_0 || ... || j_N) Review Comment: Didn't quite follow this, why is having one distinct index match in j_set sufficient to assume J is a superset? ########## src/arith/conjunctive_normal_form.cc: ########## @@ -0,0 +1,415 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/*! + * \file tvm/arith/conjunctive_normal_form.cc + */ + +#include "conjunctive_normal_form.h" + +#include <tvm/arith/analyzer.h> +#include <tvm/tir/expr.h> + +#include <optional> +#include <unordered_map> +#include <unordered_set> +#include <utility> +#include <vector> + +#include "pattern_match.h" +#include "rewrite_simplify.h" + +namespace tvm { +namespace arith { + +namespace { +/* \brief A utility for simplifying expressions using conjunctive/disjuctive normal forms */ +class AndOfOrs { + public: + /*! \brief Construct the simplifier + * + * Convert a PrimExpr to the internal representation. + * + * \param expr The PrimExpr to be simplified. + */ + explicit AndOfOrs(const PrimExpr& expr); + + /*! \brief Convert internal representation to PrimExpr */ + PrimExpr AsPrimExpr() const; + + /*! \brief Simplify the internal representation */ + void Simplify(Analyzer* analyzer); + + private: + /*! \brief Internal utility, simplify within each group of expressions + * + * For each pair of values within a chunk, attempt to simplify them into + * a single expression. + * + * For example, + * before = (a == 5) && ((b < 10) || (b > 10)) + * after = (a == 5) && ((b != 10) || false) + */ + void SimplifyWithinChunks(Analyzer* analyzer); + + /*! \brief Internal utility, simplify across groups of expressions + * + * For each pair of chunks, if the two chunks differ by only a single + * term, attempt to simplify those differing terms. + * + * For example, + * before = ((a == 5) || (b <= 10)) && ((a == 5) || (b >= 10)) + * after = ((a == 5) || (b == 10)) && ((a == 5) || true) + */ + void SimplifyAcrossChunks(Analyzer* analyzer); + + /*! \brief Remove instances of true/false from internal representation + * + * To avoid invalidating iterators, `SimplifyWithinChunks` and + * `SimplifyAcrossChunks` may replace keys, but may not remove keys from + * the internal representation. For example, `(a < 5) && (a < 10)` + * would be simplified to `(a < 5) && true`. The `Cleanup` function + * removes these leftover instances of true/false. + */ + void Cleanup(); + + /*! \brief Internal utility function used to convert to internal form */ + static void VisitAndExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback); + /*! \brief Internal utility function used to convert to internal form */ + static void VisitOrExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback); + + /* \brief Type-safe wrapper class that represents an PrimExpr + * + * Because integer indices are used frequently through this class, + * maintaining a separation between integer indices used to access + * specific elements of the internal representation, and unique + * identifiers used to represent expressions PrimExpr, is useful. + */ + enum class Key : size_t {}; + + /*! \brief Convert a PrimExpr to a Key */ + Key GetKey(const PrimExpr& expr); + + /*! \brief Convert a Key to a PrimExpr */ + PrimExpr GetExpr(Key key) const; + + /*! \brief Attempt to simplify (a && b) + * + * If successful, will overwrite the parameters `a` and `b` with the + * simplified form. + */ + void TrySimplifyOr(Key* a, Key* b, Analyzer* analyzer); + + /*! \brief Attempt to simplify (a || b) + * + * If successful, will overwrite the parameters `a` and `b` with the + * simplified form. + */ + void TrySimplifyAnd(Key* a, Key* b, Analyzer* analyzer); + + /*! \brief The internal representation + * + * `chunks[i][j]` is the j-th expression in the i-th OR-group. + */ + std::vector<std::vector<Key>> chunks; Review Comment: Please use naming convention with trailing underscore here and for other member variables. ########## src/arith/conjunctive_normal_form.cc: ########## @@ -0,0 +1,415 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/*! + * \file tvm/arith/conjunctive_normal_form.cc + */ + +#include "conjunctive_normal_form.h" + +#include <tvm/arith/analyzer.h> +#include <tvm/tir/expr.h> + +#include <optional> +#include <unordered_map> +#include <unordered_set> +#include <utility> +#include <vector> + +#include "pattern_match.h" +#include "rewrite_simplify.h" + +namespace tvm { +namespace arith { + +namespace { +/* \brief A utility for simplifying expressions using conjunctive/disjuctive normal forms */ +class AndOfOrs { + public: + /*! \brief Construct the simplifier + * + * Convert a PrimExpr to the internal representation. + * + * \param expr The PrimExpr to be simplified. + */ + explicit AndOfOrs(const PrimExpr& expr); + + /*! \brief Convert internal representation to PrimExpr */ + PrimExpr AsPrimExpr() const; + + /*! \brief Simplify the internal representation */ + void Simplify(Analyzer* analyzer); + + private: + /*! \brief Internal utility, simplify within each group of expressions + * + * For each pair of values within a chunk, attempt to simplify them into + * a single expression. + * + * For example, + * before = (a == 5) && ((b < 10) || (b > 10)) + * after = (a == 5) && ((b != 10) || false) + */ + void SimplifyWithinChunks(Analyzer* analyzer); + + /*! \brief Internal utility, simplify across groups of expressions + * + * For each pair of chunks, if the two chunks differ by only a single + * term, attempt to simplify those differing terms. + * + * For example, + * before = ((a == 5) || (b <= 10)) && ((a == 5) || (b >= 10)) + * after = ((a == 5) || (b == 10)) && ((a == 5) || true) + */ + void SimplifyAcrossChunks(Analyzer* analyzer); + + /*! \brief Remove instances of true/false from internal representation + * + * To avoid invalidating iterators, `SimplifyWithinChunks` and + * `SimplifyAcrossChunks` may replace keys, but may not remove keys from + * the internal representation. For example, `(a < 5) && (a < 10)` + * would be simplified to `(a < 5) && true`. The `Cleanup` function + * removes these leftover instances of true/false. + */ + void Cleanup(); Review Comment: nit: Prefer a more descriptive function name. Some ideas I had: `RemoveTrueFalse`, `RemoveTruthValues`, `RemoveSimplifiedTruthValues`? ########## include/tvm/arith/analyzer.h: ########## @@ -297,6 +297,14 @@ class RewriteSimplifier { * if_then_else(i<j && j<k, i<k, false) => if_then_else(i<j && j<k, true, false) */ kTransitivelyProveInequalities = (1 << 0), + + /* When simplifying a boolean expression, convert to an AND of ORs + * (conjunctive normal form). + * + * Example: + * (a || b) && c => (a && c) || (b && c) Review Comment: Isn't this example actually converting an expression in conjunctive (AND of ORs) to disjunctive (OR of ANDs) and so should be reversed? ########## tests/python/unittest/test_tir_transform_simplify.py: ########## @@ -686,5 +688,52 @@ def before(A: T.Buffer[1, "bool"], i: T.int32, j: T.int32, k: T.int32): expected = before +class TestRewriteAsAndOfOrs(BaseBeforeAfter): + """If enabled, rewrite boolean expressions into AND of OR""" + + convert_boolean_to_and_of_ors = True + + def before(A: T.Buffer[3, "bool"]): + T.evaluate(A[0] or (A[1] and A[2])) + + def expected(A: T.Buffer[3, "bool"]): + T.evaluate((A[0] or A[1]) and (A[0] or A[2])) + + +class TestSuppressRewriteAsAndOfOrs(BaseBeforeAfter): + """Only rewrite into AND of OR when allowed""" + + convert_boolean_to_and_of_ors = False + + def before(A: T.Buffer[3, "bool"]): + T.evaluate(A[0] or (A[1] and A[2])) + + expected = before + + +class TestRewriteAsAndOfOrsWithTopLevelAnd(BaseBeforeAfter): + """The expression being rewritten may start with an AND + + Like TestRewriteAsAndOfOrs, but with an AndNode as the outermost + booelan operator. Even though it is primarily OR nodes that are + being rewritten, the call to SimplifyAsAndOfOrs should apply to + the outermost AndNode or OrNode in order to enable better + simplification. + """ + + convert_boolean_to_and_of_ors = True + + def before(A: T.Buffer[4, "bool"]): + T.evaluate((A[0] or A[1]) and (A[1] or (A[0] and A[2] and A[3]))) + + def expected(A: T.Buffer[4, "bool"]): + # If the simplification is applied to the OrNode, then the + # redundant `(A[1] or A[0])` isn't canceled out + # + # T.evaluate((A[0] or A[1]) and ((A[1] or A[0]) and (A[1] or A[2]) and (A[1] or A[3]))) + # + T.evaluate((A[0] or A[1]) and (A[1] or A[2]) and (A[1] or A[3])) + + Review Comment: You've hit most of the relevant cases but maybe some additional tests now or later for coverage could provide additional assurances against things like different expression orderings, redundant expressions, and maybe others I'm not thinking of now. ########## src/arith/conjunctive_normal_form.cc: ########## @@ -0,0 +1,415 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/*! + * \file tvm/arith/conjunctive_normal_form.cc + */ + +#include "conjunctive_normal_form.h" + +#include <tvm/arith/analyzer.h> +#include <tvm/tir/expr.h> + +#include <optional> +#include <unordered_map> +#include <unordered_set> +#include <utility> +#include <vector> + +#include "pattern_match.h" +#include "rewrite_simplify.h" + +namespace tvm { +namespace arith { + +namespace { +/* \brief A utility for simplifying expressions using conjunctive/disjuctive normal forms */ +class AndOfOrs { + public: + /*! \brief Construct the simplifier + * + * Convert a PrimExpr to the internal representation. + * + * \param expr The PrimExpr to be simplified. + */ + explicit AndOfOrs(const PrimExpr& expr); + + /*! \brief Convert internal representation to PrimExpr */ + PrimExpr AsPrimExpr() const; + + /*! \brief Simplify the internal representation */ + void Simplify(Analyzer* analyzer); + + private: + /*! \brief Internal utility, simplify within each group of expressions + * + * For each pair of values within a chunk, attempt to simplify them into + * a single expression. + * + * For example, + * before = (a == 5) && ((b < 10) || (b > 10)) + * after = (a == 5) && ((b != 10) || false) + */ + void SimplifyWithinChunks(Analyzer* analyzer); + + /*! \brief Internal utility, simplify across groups of expressions + * + * For each pair of chunks, if the two chunks differ by only a single + * term, attempt to simplify those differing terms. + * + * For example, + * before = ((a == 5) || (b <= 10)) && ((a == 5) || (b >= 10)) + * after = ((a == 5) || (b == 10)) && ((a == 5) || true) + */ + void SimplifyAcrossChunks(Analyzer* analyzer); + + /*! \brief Remove instances of true/false from internal representation + * + * To avoid invalidating iterators, `SimplifyWithinChunks` and + * `SimplifyAcrossChunks` may replace keys, but may not remove keys from + * the internal representation. For example, `(a < 5) && (a < 10)` + * would be simplified to `(a < 5) && true`. The `Cleanup` function + * removes these leftover instances of true/false. + */ + void Cleanup(); + + /*! \brief Internal utility function used to convert to internal form */ + static void VisitAndExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback); + /*! \brief Internal utility function used to convert to internal form */ + static void VisitOrExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback); + + /* \brief Type-safe wrapper class that represents an PrimExpr + * + * Because integer indices are used frequently through this class, + * maintaining a separation between integer indices used to access + * specific elements of the internal representation, and unique + * identifiers used to represent expressions PrimExpr, is useful. + */ + enum class Key : size_t {}; + + /*! \brief Convert a PrimExpr to a Key */ + Key GetKey(const PrimExpr& expr); + + /*! \brief Convert a Key to a PrimExpr */ + PrimExpr GetExpr(Key key) const; + + /*! \brief Attempt to simplify (a && b) + * + * If successful, will overwrite the parameters `a` and `b` with the + * simplified form. + */ + void TrySimplifyOr(Key* a, Key* b, Analyzer* analyzer); + + /*! \brief Attempt to simplify (a || b) + * + * If successful, will overwrite the parameters `a` and `b` with the + * simplified form. + */ + void TrySimplifyAnd(Key* a, Key* b, Analyzer* analyzer); + + /*! \brief The internal representation + * + * `chunks[i][j]` is the j-th expression in the i-th OR-group. + */ + std::vector<std::vector<Key>> chunks; + + /*! \brief Mapping from internal Key to PrimExpr */ + std::unordered_map<Key, PrimExpr, StructuralHash, StructuralEqual> key_to_expr; + + /*! \brief Mapping from PrimExpr to internal Key */ + std::unordered_map<PrimExpr, Key, StructuralHash, StructuralEqual> expr_to_key; + + /*! \brief Cached key representing tir::Bool(true) */ + Key key_true; + + /*! \brief Cached key representing tir::Bool(false) */ + Key key_false; +}; + +AndOfOrs::AndOfOrs(const PrimExpr& expr) + : key_true(GetKey(Bool(true))), key_false(GetKey(Bool(false))) { + VisitAndExpressions(expr, [&](const PrimExpr& outer_expr) { + std::vector<Key> or_components; + VisitOrExpressions(outer_expr, [&](const PrimExpr& inner_expr) { + Key key = GetKey(inner_expr); + bool is_duplicate = std::any_of(or_components.begin(), or_components.end(), + [&](Key prev) { return prev == key; }); + if (!is_duplicate) { + or_components.push_back(key); + } + }); + + bool is_permutation = + std::any_of(chunks.begin(), chunks.end(), [&](const std::vector<Key>& prev_components) { + return or_components.size() == prev_components.size() && + std::is_permutation(prev_components.begin(), prev_components.end(), + or_components.begin()); + }); + if (!is_permutation) { + chunks.push_back(std::move(or_components)); + } + }); +} + +void AndOfOrs::VisitAndExpressions(const PrimExpr& expr, + std::function<void(const PrimExpr&)> callback) { + PVar<PrimExpr> x, y, z; + if ((x && y).Match(expr)) { + VisitAndExpressions(x.Eval(), callback); + VisitAndExpressions(y.Eval(), callback); + } else if ((x || y).Match(expr)) { + VisitAndExpressions(x.Eval(), [&](const PrimExpr& x_part) { + VisitAndExpressions(y.Eval(), [&](const PrimExpr& y_part) { callback(x_part || y_part); }); + }); + } else { + callback(expr); + } +} Review Comment: nit: A comment on each case could help with understanding the recursion. ########## tests/python/unittest/test_tir_transform_simplify.py: ########## @@ -686,5 +688,52 @@ def before(A: T.Buffer[1, "bool"], i: T.int32, j: T.int32, k: T.int32): expected = before +class TestRewriteAsAndOfOrs(BaseBeforeAfter): + """If enabled, rewrite boolean expressions into AND of OR""" + + convert_boolean_to_and_of_ors = True + + def before(A: T.Buffer[3, "bool"]): + T.evaluate(A[0] or (A[1] and A[2])) + + def expected(A: T.Buffer[3, "bool"]): + T.evaluate((A[0] or A[1]) and (A[0] or A[2])) + + +class TestSuppressRewriteAsAndOfOrs(BaseBeforeAfter): + """Only rewrite into AND of OR when allowed""" + + convert_boolean_to_and_of_ors = False + + def before(A: T.Buffer[3, "bool"]): + T.evaluate(A[0] or (A[1] and A[2])) + + expected = before + + +class TestRewriteAsAndOfOrsWithTopLevelAnd(BaseBeforeAfter): + """The expression being rewritten may start with an AND + + Like TestRewriteAsAndOfOrs, but with an AndNode as the outermost + booelan operator. Even though it is primarily OR nodes that are + being rewritten, the call to SimplifyAsAndOfOrs should apply to + the outermost AndNode or OrNode in order to enable better + simplification. + """ + + convert_boolean_to_and_of_ors = True + + def before(A: T.Buffer[4, "bool"]): + T.evaluate((A[0] or A[1]) and (A[1] or (A[0] and A[2] and A[3]))) + + def expected(A: T.Buffer[4, "bool"]): + # If the simplification is applied to the OrNode, then the + # redundant `(A[1] or A[0])` isn't canceled out + # + # T.evaluate((A[0] or A[1]) and ((A[1] or A[0]) and (A[1] or A[2]) and (A[1] or A[3]))) + # Review Comment: Is this a stale comment? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
