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Fix wrong runtime result when using -fno-gate (#6952) 

Signed-off-by: Charitha-Jeewanka <cjrathnayake24@gmail.com>
This commit is contained in:
Charitha-Jeewanka 2026-02-14 02:22:07 -05:00
parent 0aaf17acfd
commit e1392b81c7
2 changed files with 28 additions and 20 deletions
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35
src/V3Gate.cpp
View File

@ -1284,26 +1284,33 @@ void V3Gate::gateAll(AstNetlist* netlistp) {
graphp->removeRedundantEdgesSum(&V3GraphEdge::followAlwaysTrue);
if (dumpGraphLevel() >= 6) graphp->dumpDotFilePrefixed("gate_simp");
// Inline variables
// Inline variables (CRITICAL for downstream scheduling)
GateInline::apply(*graphp);
if (dumpGraphLevel() >= 6) graphp->dumpDotFilePrefixed("gate_inline");
// Remove redundant logic
if (v3Global.opt.fDedupe()) {
GateDedupe::apply(*graphp);
if (dumpGraphLevel() >= 6) graphp->dumpDotFilePrefixed("gate_dedup");
}
// --- NON-CRITICAL OPTIMIZATIONS ---
// Only run these aggressive logic reducers if gate optimization is enabled
if (v3Global.opt.fGate()) {
// Remove redundant logic
if (v3Global.opt.fDedupe()) {
GateDedupe::apply(*graphp);
if (dumpGraphLevel() >= 6) graphp->dumpDotFilePrefixed("gate_dedup");
}
// Merge assignments
if (v3Global.opt.fAssemble()) {
GateMergeAssignments::apply(*graphp);
if (dumpGraphLevel() >= 6) graphp->dumpDotFilePrefixed("gate_merge");
}
// Merge assignments
if (v3Global.opt.fAssemble()) {
GateMergeAssignments::apply(*graphp);
if (dumpGraphLevel() >= 6) graphp->dumpDotFilePrefixed("gate_merge");
}
// Remove unused logic
GateUnused::apply(*graphp);
if (dumpGraphLevel() >= 3) graphp->dumpDotFilePrefixed("gate_final");
// Remove unused logic
GateUnused::apply(*graphp);
if (dumpGraphLevel() >= 3) graphp->dumpDotFilePrefixed("gate_final");
} // End of fGate() check
}
V3Global::dumpCheckGlobalTree("gate", 0, dumpTreeEitherLevel() >= 3);
}

13
src/Verilator.cpp
View File

@ -420,12 +420,13 @@ static void process() {
// Gate-based logic elimination; eliminate signals and push constant across cell
// boundaries Instant propagation makes lots-o-constant reduction possibilities.
if (v3Global.opt.fGate()) {
V3Gate::gateAll(v3Global.rootp());
// V3Gate calls constant propagation itself.
} else {
v3info("Command Line disabled gate optimization with -fno-gate. "
"This may cause ordering problems.");
// Always run gateAll to perform critical downstream normalizations
// (like GateInline) even if fGate is false.
V3Gate::gateAll(v3Global.rootp());
if (!v3Global.opt.fGate()) {
v3info("Command Line disabled gate optimization with -fno-gate. "
"Only critical normalizations will be performed.");
}
// Combine COVERINCs with duplicate terms