luke/verilator
1
0
Fork 0
mirror of https://github.com/verilator/verilator.git synced 2026-09-01 10:27:04 +02:00
Code Issues Packages Projects Releases Wiki Activity

Fix cover property of an implication counting vacuous matches (#7789)

Browse Source
This commit is contained in:
Yilou Wang
2026-06-16 11:52:35 -04:00
committed by GitHub
parent 38fd99b37b
commit bec45125bd
3 changed files with 107 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/V3AssertPre.cpp
+12 -2
View File
@@ -61,6 +61,7 @@ private:
AstNodeExpr* m_disablep = nullptr; // Last disable
AstIf* m_disableSeqIfp = nullptr; // Used for handling disable iff in sequences
AstPExpr* m_pexprp = nullptr; // Last AstPExpr
bool m_underCover = false; // True if the enclosing assertion is a cover
// Other:
V3UniqueNames m_cycleDlyNames{"__VcycleDly"}; // Cycle delay counter name generator
V3UniqueNames m_consRepNames{"__VconsRep"}; // Consecutive repetition counter name generator
@@ -1282,7 +1283,10 @@ private:
// Don't iterate pexprp here -- it was already iterated when created
// (in visit(AstSExpr*)), so delays and disable iff are already processed.
} else if (nodep->isOverlapped()) {
nodep->replaceWith(new AstLogOr{flp, new AstLogNot{flp, lhsp}, rhsp});
AstNodeExpr* const exprp
= m_underCover ? static_cast<AstNodeExpr*>(new AstLogAnd{flp, lhsp, rhsp})
: new AstLogOr{flp, new AstLogNot{flp, lhsp}, rhsp};
nodep->replaceWith(exprp);
} else {
if (m_disablep) {
lhsp = new AstAnd{flp, new AstNot{flp, m_disablep->cloneTreePure(false)}, lhsp};
@@ -1291,7 +1295,9 @@ private:
AstPast* const pastp = new AstPast{flp, lhsp};
pastp->dtypeFrom(lhsp);
pastp->sentreep(newSenTree(nodep));
AstNodeExpr* const exprp = new AstOr{flp, new AstNot{flp, pastp}, rhsp};
AstNodeExpr* const exprp
= m_underCover ? static_cast<AstNodeExpr*>(new AstAnd{flp, pastp, rhsp})
: new AstOr{flp, new AstNot{flp, pastp}, rhsp};
exprp->dtypeSetBit();
nodep->replaceWith(exprp);
}
@@ -1469,6 +1475,10 @@ private:
nodep->propp(new AstSampled{nodep->fileline(), nodep->propp()->unlinkFrBack(),
propDtp->dtypep()});
}
// cover counts non-vacuous matches only (IEEE 1800-2023 16.15.2), so an
// implication antecedent must hold; assert passes vacuously instead.
VL_RESTORER(m_underCover);
m_underCover = VN_IS(nodep->backp(), Cover);
iterate(nodep->propp());
}
void visit(AstPExpr* nodep) override {