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Merge pull request #5399 from povik/opt_hier-bug

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opt_hier: Fix two optimizations conflicting
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Martin Povišer 2025-09-29 14:53:54 +02:00 • committed by GitHub
commit 04c7013f0e
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2 changed files with 39 additions and 7 deletions
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23
passes/opt/opt_hier.cc
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@ -144,12 +144,12 @@ struct ModuleIndex {
} }
if (nunused > 0) { if (nunused > 0) {
log("Disconnected %d input bits of instance '%s' of '%s' in '%s'\n", log("Disconnected %d input bits of instance '%s' (type '%s') in '%s'\n",
nunused, log_id(instantiation), log_id(instantiation->type), log_id(parent.module)); nunused, log_id(instantiation), log_id(instantiation->type), log_id(parent.module));
changed = true; changed = true;
} }
if (nconstants > 0) { if (nconstants > 0) {
log("Substituting constant for %d output bits of instance '%s' of '%s' in '%s'\n", log("Substituting constant for %d output bits of instance '%s' (type '%s') in '%s'\n",
nconstants, log_id(instantiation), log_id(instantiation->type), log_id(parent.module)); nconstants, log_id(instantiation), log_id(instantiation->type), log_id(parent.module));
changed = true; changed = true;
} }
@ -310,7 +310,7 @@ struct UsageData {
refine_tie_togethers(inputs); refine_tie_togethers(inputs);
} }
bool apply_changes() { bool apply_changes(ModuleIndex &index) {
bool did_something = false; bool did_something = false;
if (module->get_blackbox_attribute()) { if (module->get_blackbox_attribute()) {
@ -374,8 +374,16 @@ struct UsageData {
// Propagate tied-together inputs // Propagate tied-together inputs
dict<SigBit, SigBit> ties; dict<SigBit, SigBit> ties;
for (auto group : tie_together_inputs) { for (auto group : tie_together_inputs) {
for (int i = 1; i < group.size(); i++) // Only consider used inputs for a tie-together group.
ties[group[i]] = group[0]; // ModuleIndex::apply_changes might have disconnected
// unused inputs.
SigSpec filtered_group;
for (auto bit : group) {
if (index.used.check(bit))
filtered_group.append(bit);
}
for (int i = 1; i < filtered_group.size(); i++)
ties[filtered_group[i]] = filtered_group[0];
} }
SigPool applied_ties; SigPool applied_ties;
auto ties_rewrite = [&](SigSpec &signal) { auto ties_rewrite = [&](SigSpec &signal) {
@ -449,12 +457,13 @@ struct OptHierPass : Pass {
bool did_something = false; bool did_something = false;
for (auto module : d->selected_modules(RTLIL::SELECT_WHOLE_ONLY, RTLIL::SB_UNBOXED_CMDERR)) { for (auto module : d->selected_modules(RTLIL::SELECT_WHOLE_ONLY, RTLIL::SB_UNBOXED_CMDERR)) {
ModuleIndex &parent_index = indices.at(module->name);
if (usage_datas.count(module->name)) { if (usage_datas.count(module->name)) {
log_debug("Applying usage data changes to %s\n", log_id(module)); log_debug("Applying usage data changes to %s\n", log_id(module));
did_something |= usage_datas.at(module->name).apply_changes(); did_something |= usage_datas.at(module->name).apply_changes(parent_index);
} }
ModuleIndex &parent_index = indices.at(module->name);
for (auto cell : module->cells()) { for (auto cell : module->cells()) {
if (indices.count(cell->type)) { if (indices.count(cell->type)) {
log_debug("Applying changes to instance %s of %s in %s\n", log_id(cell), log_id(cell->type), log_id(module)); log_debug("Applying changes to instance %s of %s in %s\n", log_id(cell), log_id(cell->type), log_id(module));

23
tests/opt/bug5398.ys Normal file
View file

@ -0,0 +1,23 @@
read_verilog <<EOF
module tag_2x4(
input R0_clk,
input W0_clk,
output x,
);
assign x = !W0_clk;
endmodule
module top(input clock, output x, output flag);
tag_2x4 tag_ext(
.R0_clk (clock),
.W0_clk (clock),
.x (x)
);
assign flag = x ^ clock;
endmodule
EOF
hierarchy -top top
opt_hier
flatten
sat -verify -prove flag 1