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Support sequence 'throughout' operator (#7378)

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This commit is contained in:
Yilou Wang
2026-04-06 17:12:22 -04:00
committed by GitHub
parent 72b2ca5585
commit dfb7b034a5
15 changed files with 338 additions and 35 deletions
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src/V3AssertProp.cpp
+73
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@@ -422,6 +422,45 @@ class AssertPropLowerVisitor final : public VNVisitor {
VL_DO_DANGLING(nodep->deleteTree(), nodep);
}
}
void visit(AstSThroughout* nodep) override {
// IEEE 1800-2023 16.9.9: expr throughout seq
// Transform by AND-ing cond with every leaf expression in the sequence,
// and attaching cond to every delay for per-tick checking in V3AssertPre.
AstNodeExpr* const condp = nodep->lhsp()->unlinkFrBack();
AstNodeExpr* const seqp = nodep->rhsp()->unlinkFrBack();
if (AstSExpr* const sexprp = VN_CAST(seqp, SExpr)) {
// Walk all SExpr nodes: AND cond with leaf expressions, attach to delays
sexprp->foreach([&](AstSExpr* sp) {
if (sp->exprp() && !VN_IS(sp->exprp(), SExpr)) {
AstNodeExpr* const origp = sp->exprp()->unlinkFrBack();
AstLogAnd* const andp
= new AstLogAnd{origp->fileline(), condp->cloneTreePure(false), origp};
andp->dtypeSetBit();
sp->exprp(andp);
}
if (sp->preExprp() && !VN_IS(sp->preExprp(), SExpr)) {
AstNodeExpr* const origp = sp->preExprp()->unlinkFrBack();
AstLogAnd* const andp
= new AstLogAnd{origp->fileline(), condp->cloneTreePure(false), origp};
andp->dtypeSetBit();
sp->preExprp(andp);
}
if (AstDelay* const dlyp = VN_CAST(sp->delayp(), Delay)) {
dlyp->throughoutp(condp->cloneTreePure(false));
}
});
nodep->replaceWith(sexprp);
VL_DO_DANGLING(nodep->deleteTree(), nodep);
VL_DO_DANGLING(condp->deleteTree(), condp);
visit(sexprp);
} else {
// Single expression (no delay): degenerate to cond && seq
AstLogAnd* const andp = new AstLogAnd{nodep->fileline(), condp, seqp};
andp->dtypeSetBit();
nodep->replaceWith(andp);
VL_DO_DANGLING(nodep->deleteTree(), nodep);
}
}
void visit(AstNodeModule* nodep) override {
VL_RESTORER(m_modp);
m_modp = nodep;
@@ -1060,6 +1099,40 @@ class RangeDelayExpander final : public VNVisitor {
}
}
void visit(AstSThroughout* nodep) override {
// Reject throughout with range-delay sequences before FSM expansion
// would silently lose per-tick enforcement (IEEE 1800-2023 16.9.9)
if (AstSExpr* const sexprp = VN_CAST(nodep->rhsp(), SExpr)) {
if (containsRangeDelay(sexprp)) {
nodep->v3warn(E_UNSUPPORTED, "Unsupported: throughout with range delay sequence");
nodep->replaceWith(new AstConst{nodep->fileline(), AstConst::BitFalse{}});
VL_DO_DANGLING(nodep->deleteTree(), nodep);
return;
}
}
// Reject throughout with nested throughout or goto repetition
if (VN_IS(nodep->rhsp(), SThroughout) || VN_IS(nodep->rhsp(), SGotoRep)) {
nodep->v3warn(E_UNSUPPORTED, "Unsupported: throughout with complex sequence operator");
nodep->replaceWith(new AstConst{nodep->fileline(), AstConst::BitFalse{}});
VL_DO_DANGLING(nodep->deleteTree(), nodep);
return;
}
// Reject throughout with temporal SAnd/SOr (containing SExpr = multi-cycle).
// Pure boolean SAnd/SOr are OK -- AssertPropLowerVisitor lowers them to LogAnd/LogOr.
if (VN_IS(nodep->rhsp(), SAnd) || VN_IS(nodep->rhsp(), SOr)) {
bool hasSExpr = false;
nodep->rhsp()->foreach([&](const AstSExpr*) { hasSExpr = true; });
if (hasSExpr) {
nodep->v3warn(E_UNSUPPORTED,
"Unsupported: throughout with complex sequence operator");
nodep->replaceWith(new AstConst{nodep->fileline(), AstConst::BitFalse{}});
VL_DO_DANGLING(nodep->deleteTree(), nodep);
return;
}
}
iterateChildren(nodep);
}
void visit(AstNode* nodep) override { iterateChildren(nodep); }
public: