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support automatic lifetime qualifier on procedural variables

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This commit is contained in:
likeamahoney 2026-02-27 20:42:40 +03:00
parent 687a36af38
commit e9442194f2
3 changed files with 129 additions and 5 deletions
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12
frontends/ast/genrtlil.cc
View file

@ -403,6 +403,18 @@ struct AST_INTERNAL::ProcessGenerator
if (GetSize(syncrule->signal) != 1)
always->input_error("Found posedge/negedge event on a signal that is not 1 bit wide!\n");
addChunkActions(syncrule->actions, subst_lvalue_from, subst_lvalue_to, true);
// Automatic (nosync) variables must not become flip-flops: remove
// them from clocked sync rules so that proc_dff does not infer
// an unnecessary register for a purely combinational temporary.
syncrule->actions.erase(
std::remove_if(syncrule->actions.begin(), syncrule->actions.end(),
[](const RTLIL::SigSig &ss) {
for (auto &chunk : ss.first.chunks())
if (chunk.wire && chunk.wire->get_bool_attribute(ID::nosync))
return true;
return false;
}),
syncrule->actions.end());
proc->syncs.push_back(syncrule);
}
if (proc->syncs.empty()) {

18
frontends/verilog/verilog_parser.y
View file

@ -84,7 +84,7 @@
int current_function_or_task_port_id;
std::vector<char> case_type_stack;
bool do_not_require_port_stubs;
bool current_wire_rand, current_wire_const;
bool current_wire_rand, current_wire_const, current_wire_automatic;
bool current_modport_input, current_modport_output;
bool default_nettype_wire = true;
std::istream* lexin;
@ -958,14 +958,18 @@ delay:
non_opt_delay | %empty;
io_wire_type:
{ extra->astbuf3 = std::make_unique<AstNode>(@$, AST_WIRE); extra->current_wire_rand = false; extra->current_wire_const = false; }
{ extra->astbuf3 = std::make_unique<AstNode>(@$, AST_WIRE); extra->current_wire_rand = false; extra->current_wire_const = false; extra->current_wire_automatic = false; }
wire_type_token_io wire_type_const_rand opt_wire_type_token wire_type_signedness
{ $$ = std::move(extra->astbuf3); SET_RULE_LOC(@$, @2, @$); };
non_io_wire_type:
{ extra->astbuf3 = std::make_unique<AstNode>(@$, AST_WIRE); extra->current_wire_rand = false; extra->current_wire_const = false; }
wire_type_const_rand wire_type_token wire_type_signedness
{ $$ = std::move(extra->astbuf3); SET_RULE_LOC(@$, @2, @$); };
{ extra->astbuf3 = std::make_unique<AstNode>(@$, AST_WIRE); extra->current_wire_rand = false; extra->current_wire_const = false; extra->current_wire_automatic = false; }
opt_lifetime wire_type_const_rand wire_type_token wire_type_signedness
{
if (extra->current_wire_automatic)
extra->astbuf3->set_attribute(ID::nosync, AstNode::mkconst_int(extra->astbuf3->location, 1, false));
$$ = std::move(extra->astbuf3); SET_RULE_LOC(@$, @2, @$);
};
wire_type:
io_wire_type { $$ = std::move($1); } |
@ -1253,6 +1257,10 @@ opt_automatic:
TOK_AUTOMATIC |
%empty;
opt_lifetime:
TOK_AUTOMATIC { extra->current_wire_automatic = true; } |
%empty;
task_func_args_opt:
TOK_LPAREN TOK_RPAREN | %empty | TOK_LPAREN {
extra->albuf = nullptr;