1/*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19
20/*!
21 * Lower block init stmt into branch stmt
22 * \file lower_reduction.cc
23 */
24#include <tvm/tir/op.h>
25#include <tvm/tir/stmt_functor.h>
26#include <tvm/tir/transform.h>
27
28#include "ir_utils.h"
29
30namespace tvm {
31namespace tir {
32
33class InitBlockLower : public StmtMutator {
34 private:
35 Stmt VisitStmt_(const BlockNode* block) final {
36 if (!block->init.defined()) {
37 return StmtMutator::VisitStmt_(block);
38 }
39 Stmt init = DoLowering(block->init.value(), block->iter_vars);
40 Stmt body = VisitStmt(block->body);
41 auto n = CopyOnWrite(block);
42 n->init = NullOpt;
43 n->body = SeqStmt::Flatten(init, body);
44 return Block(n);
45 }
46
47 static Stmt DoLowering(const Stmt& init, const Array<IterVar>& iter_vars) {
48 std::vector<PrimExpr> conditions;
49 for (const IterVar& var : iter_vars) {
50 if (var->iter_type == IterVarType::kCommReduce) {
51 conditions.push_back(equal(var->var, var->dom->min));
52 }
53 }
54 // Handle the case where there is no condition
55 if (conditions.empty()) {
56 return init;
57 }
58 // Concat the conditions with logical and (&&)
59 PrimExpr cond = conditions[0];
60 for (size_t i = 1; i < conditions.size(); ++i) {
61 cond = logical_and(cond, conditions[i]);
62 }
63 return IfThenElse(cond, init);
64 }
65};
66
67PrimFunc LowerInitBlock(PrimFunc func) {
68 // Only apply this pass to TIR that is not from TE schedules
69 if (!IsFromLegacyTESchedule(func)) {
70 auto fptr = func.CopyOnWrite();
71 fptr->body = InitBlockLower()(std::move(fptr->body));
72 return func;
73 } else {
74 return func;
75 }
76}
77
78namespace transform {
79
80Pass LowerInitBlock() {
81 auto pass_func = [](PrimFunc f, IRModule m, PassContext ctx) {
82 return LowerInitBlock(std::move(f));
83 };
84 return CreatePrimFuncPass(pass_func, 0, "tir.LowerInitBlock", {});
85}
86
87TVM_REGISTER_GLOBAL("tir.transform.LowerInitBlock").set_body_typed(LowerInitBlock);
88
89} // namespace transform
90
91} // namespace tir
92} // namespace tvm
93