yzhliu commented on a change in pull request #5092: [PASS] dtype rewrite for indexing variables URL: https://github.com/apache/incubator-tvm/pull/5092#discussion_r395450594
########## File path: src/tir/pass/rewrite_datatype.cc ########## @@ -0,0 +1,326 @@ +/* + * 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 rewrite_datatype.cc + * \brief narrow the datatype of indexing vars + */ + +#include <tvm/tir/ir_pass.h> +#include <tvm/tir/op.h> +#include "../../arith/ir_mutator_with_analyzer.h" +#include "../../arith/ir_visitor_with_analyzer.h" + +namespace tvm { +namespace tir { + +using arith::Analyzer; +using arith::IRMutatorWithAnalyzer; +using arith::ConstIntBound; + +class DataTypeRewriter; + +class DataTypeVisitor final : public StmtExprVisitor { + public: + void VisitExpr(const PrimExpr& e) { + if (e.dtype().is_int()) { + int bits = 64; + if (e.dtype().bits() <= 32 || + analyzer_.CanProve(e <= max_value(DataType::Int(32)) && + e >= min_value(DataType::Int(32)))) { + bits = 32; + } + int tmp = bits_; + bits_ = bits > bits_ ? bits : bits_; + StmtExprVisitor::VisitExpr(e); + bits_ = tmp; + } else { + StmtExprVisitor::VisitExpr(e); + } + } + + void VisitStmt_(const ForNode* op) { + analyzer_.Bind(op->loop_var, + Range::make_by_min_extent(op->min, op->extent)); + vextent_[op->loop_var.as<VarNode>()] = op->extent.dtype(); + return StmtExprVisitor::VisitStmt_(op); + } + + void VisitStmt_(const AttrStmtNode* op) { + if (op->attr_key == attr::thread_extent || + op->attr_key == attr::virtual_thread) { + IterVar iv = Downcast<IterVar>(op->node); + CHECK_NE(iv->thread_tag.length(), 0U); + analyzer_.Bind(iv->var, + Range::make_by_min_extent(0, op->value)); + vextent_[iv->var.as<VarNode>()] = op->value.dtype(); + StmtExprVisitor::VisitStmt_(op); + } else { + StmtExprVisitor::VisitStmt_(op); + } + } + + void VisitExpr_(const ReduceNode* op) { + // Setup the domain information before simplification. + for (const IterVar& iv : op->axis) { + analyzer_.Bind(iv->var, iv->dom); + vextent_[iv->var.as<VarNode>()] = iv->dom->extent.dtype(); + } + // Recursively call simplification when necessary. + StmtExprVisitor::VisitExpr_(op); + } + + void VisitExpr_(const VarNode* op) { + if (vextent_.find(op) != vextent_.end()) { + int bits = std::min(vextent_[op].bits(), bits_); + if (vmap.find(op) == vmap.end()) { + vmap[op] = op->dtype.with_bits(bits); + } else { + vmap[op] = op->dtype.with_bits(std::max(vmap[op].bits(), bits)); + } + } + StmtExprVisitor::VisitExpr_(op); + } + + void VisitExpr_(const IntImmNode* op) { + if (op->dtype.is_int()) { + int bits = std::min(op->dtype.bits(), bits_); + if (vmap.find(op) == vmap.end()) { + vmap[op] = op->dtype.with_bits(bits); + } else { + vmap[op] = op->dtype.with_bits(std::max(vmap[op].bits(), bits)); + } + } + StmtExprVisitor::VisitExpr_(op); + } + + void VisitExpr_(const CastNode* op) { + if (op->dtype.is_int()) { + int bits = std::min(op->dtype.bits(), bits_); + if (vmap.find(op) == vmap.end()) { + vmap[op] = op->dtype.with_bits(bits); + } else { + vmap[op] = op->dtype.with_bits(std::max(vmap[op].bits(), bits)); + } + } + StmtExprVisitor::VisitExpr_(op); + } + + // the narrowed datatype of Var and IntImm + std::unordered_map<const PrimExprNode*, DataType> vmap; + + protected: + // internal analyzer + arith::Analyzer analyzer_; + + private: + // the maximum possible bit of the current expression's return dtype + int bits_; + // the extent of vars to be rewritten + std::unordered_map<const VarNode*, DataType> vextent_; +}; + +class DataTypeRewriter : public StmtExprMutator { + public: + Stmt operator()(Stmt s) { + visitor_(s); + for (auto i = visitor_.vmap.begin(), last = visitor_.vmap.end(); i != last;) { + PrimExpr e = GetRef<PrimExpr>(i->first); + if (e.dtype() == i->second) { + i = visitor_.vmap.erase(i); + } else { + ++i; + } + } + return VisitStmt(s); + } + + Stmt VisitStmt_(const StoreNode* op) final { + PrimExpr value = this->VisitExpr(op->value); + is_index_ = true; + PrimExpr index = this->VisitExpr(op->index); + is_index_ = false; + Stmt s = StoreNode::make(op->buffer_var, + op->value, + index, + op->predicate); + return StmtExprMutator::VisitStmt_(s.as<StoreNode>()); + } + + Stmt VisitStmt_(const ForNode* op) final { + Stmt s = StmtExprMutator::VisitStmt_(op); + op = s.as<ForNode>(); + PrimExpr e = VisitExpr(op->loop_var); + Var var = Downcast<Var, PrimExpr>(e); + return ForNode::make(var, cast(var.dtype(), op->min), cast(var.dtype(), op->extent), + op->for_type, op->device_api, op->body); + } + + Stmt VisitStmt_(const AttrStmtNode* op) final { + if (op->attr_key == attr::thread_extent || + op->attr_key == attr::virtual_thread) { + Stmt s = StmtExprMutator::VisitStmt_(op); + op = s.as<AttrStmtNode>(); + const IterVarNode* iv = op->node.as<IterVarNode>(); + PrimExpr e = VisitExpr(iv->var); + Var var = Downcast<Var, PrimExpr>(e); + if (ivmap_.find(iv) == ivmap_.end()) { + ivmap_[iv] = IterVarNode::make(iv->dom, var, iv->iter_type, iv->thread_tag); + } + return AttrStmtNode::make( + ivmap_[iv], + op->attr_key, + cast(var.dtype(), op->value), + op->body); + } + return StmtExprMutator::VisitStmt_(op); + } + + PrimExpr VisitExpr_(const VarNode* op) final { + if (visitor_.vmap.find(op) != visitor_.vmap.end()) { + if (vmap_.find(op) == vmap_.end()) { + vmap_[op] = Var(op->name_hint, visitor_.vmap[op]); + } + return vmap_[op]; + } + return StmtExprMutator::VisitExpr_(op); + } + + PrimExpr VisitExpr_(const SizeVarNode* op) final { + if (visitor_.vmap.find(op) != visitor_.vmap.end()) { + if (vmap_.find(op) == vmap_.end()) { + vmap_[op] = SizeVar(op->name_hint, visitor_.vmap[op]); + } + return vmap_[op]; + } + return StmtExprMutator::VisitExpr_(op); + } + + PrimExpr VisitExpr_(const LoadNode* op) final { + is_index_ = true; + PrimExpr index = this->VisitExpr(op->index); + is_index_ = false; + PrimExpr e = LoadNode::make(op->dtype, op->buffer_var, index, op->predicate); + return StmtExprMutator::VisitExpr_(e.as<LoadNode>()); + } + + PrimExpr VisitExpr_(const IntImmNode* op) final { + if (is_index_) { + if (visitor_.vmap.find(op) != visitor_.vmap.end()) { + return IntImm(visitor_.vmap[op], op->value); + } + } + return StmtExprMutator::VisitExpr_(op); + } + + PrimExpr VisitExpr_(const CastNode* op) final { + if (is_index_ && visitor_.vmap.find(op) != visitor_.vmap.end()) { + PrimExpr e = StmtExprMutator::VisitExpr_(op); + const CastNode* new_op = e.as<CastNode>(); Review comment: assert new_op != nullptr ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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