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/*
* 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.
*/
/*!
* \brief Replace certain copy with copy intrinsics.
* \file copy_intrin_rewrite.cc
*/
#include <tvm/arith/analyzer.h>
#include <tvm/arith/pattern.h>
#include <tvm/runtime/registry.h>
#include <tvm/tir/expr.h>
#include <tvm/tir/stmt_functor.h>
#include <tvm/tir/transform.h>
#include "../../arith/pattern_match.h"
namespace tvm {
namespace tir {
using runtime::PackedFunc;
class CopyIntrinInjector : public StmtMutator {
public:
CopyIntrinInjector(const std::string& pragma_key, const PackedFunc& flower_copy_fromto)
: pragma_key_(attr::pragma_scope_prefix + pragma_key),
flower_copy_fromto_(flower_copy_fromto) {}
Stmt VisitStmt_(const AttrStmtNode* op) final {
if (op->attr_key == attr::storage_scope) {
const VarNode* buf = op->node.as<VarNode>();
storage_scope_[buf] = op->value.as<StringImmNode>()->value;
} else if (op->attr_key == pragma_key_) {
Stmt ret;
CHECK(MatchCopyPattern(op->body, &ret)) << "Cannot match copy pattern of " << op->body;
return ret;
}
return StmtMutator::VisitStmt_(op);
}
private:
bool MatchCopyPattern(Stmt stmt, Stmt* out) {
using namespace arith;
Stmt body = stmt;
// strip the loops
std::vector<const ForNode*> loops;
while (const ForNode* op = body.as<ForNode>()) {
if (!is_zero(op->min)) return false;
loops.push_back(op);
body = op->body;
}
const StoreNode* store = body.as<StoreNode>();
if (store == nullptr) return false;
// Expr sel_cond, sel_true_value, sel_false_value;
// match select or if
PVar<PrimExpr> sel_cond, sel_true_value, sel_false_value;
bool has_cond = if_then_else(sel_cond, sel_true_value, sel_false_value).Match(store->value) ||
select(sel_cond, sel_true_value, sel_false_value).Match(store->value);
const CastNode* cast = store->value.as<CastNode>();
const LoadNode* load = store->value.as<LoadNode>();
if (0 == loops.size()) {
CHECK(!has_cond);
}
// for now only support true condition matching
if (has_cond) {
load = sel_true_value.Eval().as<LoadNode>();
}
// cast can be part of the pattern
if (cast != nullptr) {
load = cast->value.as<LoadNode>();
}
if (load == nullptr) return false;
if (load->dtype.lanes() != 1) return false;
Array<Var> loop_vars;
for (const ForNode* op : loops) {
loop_vars.push_back(op->loop_var);
}
Array<PrimExpr> store_strides = arith::DetectLinearEquation(store->index, loop_vars);
Array<PrimExpr> load_strides = arith::DetectLinearEquation(load->index, loop_vars);
if (load_strides.size() == 0 || store_strides.size() == 0) return false;
Array<PrimExpr> dst_shape;
const size_t loop_var_size = loop_vars.size();
if (loop_var_size == 0) {
dst_shape.push_back(make_const(DataType::Int(32), 1));
} else {
for (const ForNode* op : loops) {
dst_shape.push_back(op->extent);
}
}
Array<PrimExpr> src_shape = dst_shape;
Array<PrimExpr> pad_before, pad_after;
PrimExpr pad_value;
PrimExpr src_elem_offset = load_strides[loop_var_size];
if (has_cond) {
Array<PrimExpr> clip_bound = arith::DetectClipBound(sel_cond.Eval(), loop_vars);
pad_value = sel_false_value.Eval();
if (clip_bound.size() == 0) return false;
CHECK_EQ(src_shape.size(), loop_vars.size());
CHECK_EQ(clip_bound.size(), loop_vars.size() * 2);
for (size_t i = 0; i < src_shape.size(); ++i) {
PrimExpr min_value = clip_bound[2 * i];
PrimExpr max_value = clip_bound[2 * i + 1];
DataType t = loop_vars[i].dtype();
PrimExpr svalue = src_shape[i];
if (min_value.defined()) {
PrimExpr pbefore = analyzer_.Simplify(Max(min_value, make_zero(t)));
src_elem_offset = src_elem_offset + pbefore * load_strides[i];
svalue = svalue - pbefore;
pad_before.push_back(pbefore);
} else {
pad_before.push_back(make_zero(t));
}
if (max_value.defined()) {
PrimExpr pafter = analyzer_.Simplify(
max(loops[i]->extent - max_value - make_const(t, 1), make_zero(t)));
svalue = svalue - pafter;
pad_after.push_back(pafter);
} else {
pad_after.push_back(make_zero(t));
}
src_shape.Set(i, analyzer_.Simplify(svalue));
}
src_elem_offset = analyzer_.Simplify(src_elem_offset);
}
CHECK_EQ(load_strides.size(), store_strides.size());
CHECK_EQ(load_strides.size(), loop_var_size + 1);
Array<PrimExpr> src_strides(load_strides.begin(), load_strides.begin() + loop_var_size);
Array<PrimExpr> dst_strides(store_strides.begin(), store_strides.begin() + loop_var_size);
if (loop_var_size == 0) {
src_strides.push_back(make_const(DataType::Int(32), 1));
dst_strides.push_back(make_const(DataType::Int(32), 1));
}
Buffer dst = Buffer(store->buffer_var, store->value.dtype(), dst_shape, dst_strides,
store_strides[loop_var_size], store->buffer_var->name_hint,
GetStorageScope(store->buffer_var.get()), 0, 0, kDefault);
Buffer src = Buffer(load->buffer_var, load->dtype, src_shape, src_strides, src_elem_offset,
load->buffer_var->name_hint, GetStorageScope(load->buffer_var.get()), 0, 0,
kDefault);
*out = flower_copy_fromto_(src, dst, pad_before, pad_after, pad_value);
CHECK(out->defined()) << "flower function did not return correct stmt";
return true;
}
// Get storage scope
std::string GetStorageScope(const VarNode* var) const {
auto it = storage_scope_.find(var);
if (it != storage_scope_.end()) {
return it->second;
} else {
return "";
}
}
// pragma key
std::string pragma_key_;
// function to lower copy intrinsics.
const PackedFunc& flower_copy_fromto_;
// Storage scope
std::unordered_map<const VarNode*, std::string> storage_scope_;
// arith analyzer
arith::Analyzer analyzer_;
};
Stmt InjectCopyIntrin(Stmt stmt, const std::string& pragma_key,
const PackedFunc& flower_copy_fromto) {
return CopyIntrinInjector(pragma_key, flower_copy_fromto)(std::move(stmt));
}
namespace transform {
Pass InjectCopyIntrin(String pragma_key, PackedFunc flower_copy_fromto) {
auto pass_func = [=](PrimFunc f, IRModule m, PassContext ctx) {
auto* n = f.CopyOnWrite();
n->body = CopyIntrinInjector(pragma_key, flower_copy_fromto)(std::move(n->body));
return f;
};
return CreatePrimFuncPass(pass_func, 0, "tir.InjectCopyIntrin", {});
}
TVM_REGISTER_GLOBAL("tir.transform.InjectCopyIntrin").set_body_typed(InjectCopyIntrin);
} // namespace transform
} // namespace tir
} // namespace tvm