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simplify: fast lookup for expand_genblock 

$pmux have bad runtime behavior with large cases and output
bit widths.

Signed-off-by: Ethan Mahintorabi <ethanmoon@google.com>
This commit is contained in:
Ethan Mahintorabi 2026-04-17 04:01:17 +00:00 committed by Emil J. Tywoniak
parent a966d06524
commit 4a4e8612b8
2 changed files with 60 additions and 35 deletions
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3
frontends/ast/ast.h
View File

@ -262,7 +262,10 @@ namespace AST
bool simplify(bool const_fold, int stage, int width_hint, bool sign_hint);
void replace_result_wire_name_in_function(const std::string &from, const std::string &to);
std::unique_ptr<AstNode> readmem(bool is_readmemh, std::string mem_filename, AstNode *memory, int start_addr, int finish_addr, bool unconditional_init);
dict<std::string, AstNode*> generate_module_fast_lookup_for_genblock_expansion();
void add_to_module_fast_lookup(dict<std::string, AstNode*>& module_fast_lookup, AstNode* node);
void expand_genblock(const std::string &prefix);
void expand_genblock(const std::string &prefix, dict<std::string, AstNode*>& module_fast_lookup);
void label_genblks(std::set<std::string>& existing, int &counter);
void mem2reg_as_needed_pass1(dict<AstNode*, pool<std::string>> &mem2reg_places,
dict<AstNode*, uint32_t> &mem2reg_flags, dict<AstNode*, uint32_t> &proc_flags, uint32_t &status_flags);

92
frontends/ast/simplify.cc
View File

@ -2616,7 +2616,7 @@ bool AstNode::simplify(bool const_fold, int stage, int width_hint, bool sign_hin
current_block->children[current_block_idx].get() != current_block_child)
current_block_idx++;
}
dict<std::string, AstNode*> module_fast_lookup = current_ast_mod->generate_module_fast_lookup_for_genblock_expansion();
while (1)
{
// eval 2nd expression
@ -2652,13 +2652,15 @@ bool AstNode::simplify(bool const_fold, int stage, int width_hint, bool sign_hin
local_index->str = "\\" + local_index->str.substr(pos + 1);
local_index->str = prefix_id(prefix, local_index->str);
current_scope[local_index->str] = local_index.get();
add_to_module_fast_lookup(module_fast_lookup, local_index.get());
current_ast_mod->children.push_back(std::move(local_index));
buf->expand_genblock(prefix);
buf->expand_genblock(prefix, module_fast_lookup);
if (type == AST_GENFOR) {
for (size_t i = 0; i < buf->children.size(); i++) {
buf->children[i]->simplify(const_fold, stage, -1, false);
add_to_module_fast_lookup(module_fast_lookup, buf->children[i].get());
current_ast_mod->children.push_back(std::move(buf->children[i]));
}
} else {
@ -4826,10 +4828,56 @@ std::unique_ptr<AstNode> AstNode::readmem(bool is_readmemh, std::string mem_file
return block;
}
void AstNode::add_to_module_fast_lookup(dict<std::string, AstNode*>& module_fast_lookup, AstNode* node)
{
if (node == nullptr){
return;
}
switch (node->type) {
case AST_PARAMETER:
case AST_LOCALPARAM:
case AST_WIRE:
case AST_AUTOWIRE:
case AST_GENVAR:
case AST_MEMORY:
case AST_FUNCTION:
case AST_TASK:
case AST_DPI_FUNCTION:
module_fast_lookup[node->str] = node;
break;
case AST_ENUM:
module_fast_lookup[node->str] = node;
current_scope[node->str] = node;
for (auto& enum_node : node->children) {
log_assert(enum_node->type == AST_ENUM_ITEM);
module_fast_lookup[enum_node->str] = enum_node.get();
}
break;
default:
break;
}
}
dict<std::string, AstNode*> AstNode::generate_module_fast_lookup_for_genblock_expansion()
{
dict<std::string, AstNode*> module_fast_lookup;
for (auto& node : current_ast_mod->children) {
add_to_module_fast_lookup(module_fast_lookup, node.get());
}
return module_fast_lookup;
}
void AstNode::expand_genblock(const std::string &prefix)
{
dict<std::string, AstNode*> module_fast_lookup = generate_module_fast_lookup_for_genblock_expansion();
expand_genblock(prefix, module_fast_lookup);
}
// annotate the names of all wires and other named objects in a named generate
// or procedural block; nested blocks are themselves annotated such that the
// prefix is carried forward, but resolution of their children is deferred
void AstNode::expand_genblock(const std::string &prefix)
void AstNode::expand_genblock(const std::string &prefix, dict<std::string, AstNode*>& module_fast_lookup)
{
if (type == AST_IDENTIFIER || type == AST_FCALL || type == AST_TCALL || type == AST_WIRETYPE || type == AST_PREFIX) {
log_assert(!str.empty());
@ -4954,36 +5002,10 @@ void AstNode::expand_genblock(const std::string &prefix)
}
}
if (current_scope.count(identifier_str) == 0) {
AstNode *current_scope_ast = (current_ast_mod == nullptr) ? current_ast : current_ast_mod;
for (auto& node : current_scope_ast->children) {
switch (node->type) {
case AST_PARAMETER:
case AST_LOCALPARAM:
case AST_WIRE:
case AST_AUTOWIRE:
case AST_GENVAR:
case AST_MEMORY:
case AST_FUNCTION:
case AST_TASK:
case AST_DPI_FUNCTION:
if (prefix_id(new_prefix, identifier_str) == node->str) {
is_resolved = true;
current_scope[node->str] = node.get();
}
break;
case AST_ENUM:
current_scope[node->str] = node.get();
for (auto& enum_node : node->children) {
log_assert(enum_node->type==AST_ENUM_ITEM);
if (prefix_id(new_prefix, identifier_str) == enum_node->str) {
is_resolved = true;
current_scope[enum_node->str] = enum_node.get();
}
}
break;
default:
break;
}
std::string new_name = prefix_id(new_prefix, identifier_str);
if (module_fast_lookup.count(new_name)) {
current_scope[new_name] = module_fast_lookup[new_name];
is_resolved = true;
}
}
}
@ -5012,7 +5034,7 @@ void AstNode::expand_genblock(const std::string &prefix)
// then restore the previous string
if (type == AST_PREFIX && i == 1) {
std::string backup_scope_name = child->str;
child->expand_genblock(prefix);
child->expand_genblock(prefix, module_fast_lookup);
child->str = backup_scope_name;
continue;
}
@ -5023,7 +5045,7 @@ void AstNode::expand_genblock(const std::string &prefix)
if ((child->type == AST_GENBLOCK || child->type == AST_BLOCK) && !child->str.empty())
continue;
child->expand_genblock(prefix);
child->expand_genblock(prefix, module_fast_lookup);
}
}