hzfan commented on a change in pull request #5092: [PASS] dtype rewrite for indexing variables URL: https://github.com/apache/incubator-tvm/pull/5092#discussion_r395701694
########## 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>(); + return CastNode::make(visitor_.vmap[op], new_op->value); + } + return StmtExprMutator::VisitExpr_(op); + } + + PrimExpr VisitExpr_(const AddNode* op) final; + PrimExpr VisitExpr_(const SubNode* op) final; + PrimExpr VisitExpr_(const MulNode* op) final; + PrimExpr VisitExpr_(const DivNode* op) final; + PrimExpr VisitExpr_(const ModNode* op) final; + PrimExpr VisitExpr_(const FloorDivNode* op) final; + PrimExpr VisitExpr_(const FloorModNode* op) final; + PrimExpr VisitExpr_(const MinNode* op) final; + PrimExpr VisitExpr_(const MaxNode* op) final; + PrimExpr VisitExpr_(const EQNode* op) final; + PrimExpr VisitExpr_(const NENode* op) final; + PrimExpr VisitExpr_(const LTNode* op) final; + PrimExpr VisitExpr_(const LENode* op) final; + PrimExpr VisitExpr_(const GTNode* op) final; + PrimExpr VisitExpr_(const GENode* op) final; + PrimExpr VisitExpr_(const CallNode* op) final; + + private: + // the internal visitor to deduce the narrowed dtype + DataTypeVisitor visitor_; + // a map from Var before rewrite to that after rewrite, + // ensures one old Var maps to exactly one new Var + std::unordered_map<const VarNode*, Var> vmap_; + // a map from IterVar before rewrite to that after rewrite, + // ensures one old IterVar maps to exactly one new IterVar + std::unordered_map<const IterVarNode*, IterVar> ivmap_; + bool is_index_{false}; +}; + +#define DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(OP, FUNC) \ + PrimExpr DataTypeRewriter::VisitExpr_(const OP* op) { \ + PrimExpr a = this->VisitExpr(op->a); \ + PrimExpr b = this->VisitExpr(op->b); \ + if (a.same_as(op->a) && \ + b.same_as(op->b)) { \ + return GetRef<PrimExpr>(op); \ + } else { \ + return FUNC(a, b); \ + } \ + } + +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(AddNode, operator+) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(SubNode, operator-) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(MulNode, operator*) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(DivNode, div) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(ModNode, truncmod) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(FloorDivNode, floordiv) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(FloorModNode, floormod) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(MinNode, min) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(MaxNode, max) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(EQNode, operator==) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(NENode, operator!=) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(LTNode, operator <) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(LENode, operator<=) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(GTNode, operator >) +DEFINE_BIOP_EXPR_MUTATE_WITH_TYPE_MATCH(GENode, operator>=) + +PrimExpr DataTypeRewriter::VisitExpr_(const CallNode* op) { + PrimExpr e = StmtExprMutator::VisitExpr_(op); + op = e.as<CallNode>(); + if (op->call_type == CallNode::PureIntrinsic) { + if (op->name == intrinsic::tvm_if_then_else) { + return if_then_else(op->args[0], op->args[1], op->args[2]); Review comment: It invokes `BinaryOpMatchTypes` to match the dtype of its two operands (For example, i32 + i64 gets converted to i64 + i64). Since I rewrite the dtype of some Var, I may break the rule that different operands of one operation must share one dtype. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
