/* * 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 stmt_simplify.cc * \brief Statement simplifier based on analyzer */ #include <tvm/tir/expr.h> #include <tvm/tir/ir_pass.h> #include <tvm/arith/analyzer.h> #include <tvm/tir/op.h> #include <tvm/arith/analyzer.h> #include "ir_mutator_with_analyzer.h" namespace tvm { namespace arith { using namespace tir; class StmtSimplifier : public IRMutatorWithAnalyzer { public: explicit StmtSimplifier(Analyzer* analyzer) : IRMutatorWithAnalyzer(analyzer) {} using Parent = IRMutatorWithAnalyzer; using Parent::VisitStmt; using Parent::VisitStmt_; PrimExpr VisitExpr(const PrimExpr& expr) final { return analyzer_->Simplify(expr); } Stmt Simplify(Stmt stmt) { return operator()(std::move(stmt)); } Stmt VisitStmt_(const ForNode* op) final { analyzer_->Bind(op->loop_var, Range::make_by_min_extent(op->min, op->extent)); With<ConstraintContext> ctx1(analyzer_, op->loop_var >= op->min); With<ConstraintContext> ctx2(analyzer_, op->loop_var < op->min + op->extent); return Parent::VisitStmt_(op); } Stmt VisitStmt_(const LetStmtNode* op) { PrimExpr value = this->VisitExpr(op->value); if (!tir::HasSideEffect(value)) { // it is fine to discard the let binding // because the call to simplify will always inline the var. analyzer_->Bind(op->var, value); return this->VisitStmt(op->body); } Stmt body = this->VisitStmt(op->body); if (value.same_as(op->value) && body.same_as(op->body)) { return GetRef<Stmt>(op); } else { auto n = this->CopyOnWrite(op); n->value = std::move(value); n->body = std::move(body); return Stmt(n); } } // eliminate useless stores Stmt VisitStmt_(const StoreNode* op) final { Stmt stmt = Parent::VisitStmt_(op); op = stmt.as<StoreNode>(); if (const LoadNode* load = op->value.as<LoadNode>()) { if (load->buffer_var.same_as(op->buffer_var) && Equal(load->index, op->index)) { return EvaluateNode::make(0); } } return GetRef<Stmt>(op); } }; } // namespace arith namespace tir { Stmt CanonicalSimplify(Stmt stmt, Map<Var, Range> vrange) { arith::Analyzer analyzer; for (auto kv : vrange) { analyzer.Bind(kv.first, kv.second); } return arith::StmtSimplifier(&analyzer).Simplify(std::move(stmt)); } PrimExpr CanonicalSimplify(PrimExpr expr, Map<Var, Range> vrange) { arith::Analyzer analyzer; for (auto kv : vrange) { analyzer.Bind(kv.first, kv.second); } return analyzer.canonical_simplify(expr); } PrimExpr Simplify(PrimExpr expr, Map<Var, Range> vrange) { arith::Analyzer analyzer; for (auto kv : vrange) { analyzer.Bind(kv.first, kv.second); } expr = analyzer.Simplify(expr); return expr; } Stmt Simplify(Stmt stmt, Map<Var, Range> vrange) { return CanonicalSimplify(std::move(stmt), vrange); } } // namespace tir } // namespace tvm