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Fix inlined expression with assignment under LHS of NBA (#5736) (#5740)

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This commit is contained in:
Geza Lore
2025-01-20 07:23:10 -05:00
committed by GitHub
parent 4954e76b28
commit f4a01eb452
3 changed files with 147 additions and 13 deletions
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src/V3Delayed.cpp
+27 -13
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@@ -208,6 +208,7 @@ class DelayedVisitor final : public VNVisitor {
// NODE STATE
// AstVar::user1() -> bool. Set true if already issued MULTIDRIVEN warning
// AstVarRef::user1() -> bool. Set true if target of NBA
// AstAssignDly::user1() -> bool. Set true if already visited
// AstNodeModule::user1p() -> std::unorded_map<std::string, AstVar*> temp map via m_varMap
// AstVarScope::user1p() -> VarScopeInfo via m_vscpInfo
// AstVarScope::user2p() -> AstVarRef*: First write reference to the Variable
@@ -909,6 +910,9 @@ class DelayedVisitor final : public VNVisitor {
VL_DO_DANGLING(nodep->deleteTree(), nodep);
}
void visit(AstAssignDly* nodep) override {
// Prevent double processing due to AstExprStmt being moved before this node
if (nodep->user1SetOnce()) return;
if (m_cfuncp) {
if (!v3Global.rootp()->nbaEventp()) {
nodep->v3warn(
@@ -922,21 +926,31 @@ class DelayedVisitor final : public VNVisitor {
UASSERT_OBJ(m_inSuspendableOrFork || m_activep->hasClocked(), nodep,
"<= assignment in non-clocked block, should have been converted in V3Active");
// Grab the reference to the target of the NBA
// Grab the reference to the target of the NBA, also lift ExprStmt statements on the LHS
VL_RESTORER(m_currNbaLhsRefp);
UASSERT_OBJ(!m_currNbaLhsRefp, nodep, "NBAs should not nest");
nodep->lhsp()->foreach([&](AstVarRef* nodep) {
// Ignore reads (e.g.: '_[*here*] <= _')
if (nodep->access().isReadOnly()) return;
// A RW ref on the LHS (e.g.: '_[preInc(*here*)] <= _') is asking for trouble at this
// point. These should be lowered in an earlier pass into sequenced temporaries.
UASSERT_OBJ(!nodep->access().isRW(), nodep, "RW ref on LHS of NBA");
// Multiple target variables
// (e.g.: '{*here*, *and here*} <= _',or '*here*[*and here* = _] <= _').
// These should be lowered in an earlier pass into sequenced statements.
UASSERT_OBJ(!m_currNbaLhsRefp, nodep, "Multiple Write refs on LHS of NBA");
// Hold on to it
m_currNbaLhsRefp = nodep;
nodep->lhsp()->foreach([&](AstNode* currp) {
if (AstExprStmt* const exprp = VN_CAST(currp, ExprStmt)) {
// Move statements before the NBA
nodep->addHereThisAsNext(exprp->stmtsp()->unlinkFrBackWithNext());
// Replace with result
currp->replaceWith(exprp->resultp()->unlinkFrBack());
// Get rid of the AstExprStmt
VL_DO_DANGLING(pushDeletep(currp), currp);
} else if (AstVarRef* const refp = VN_CAST(currp, VarRef)) {
// Ignore reads (e.g.: '_[*here*] <= _')
if (refp->access().isReadOnly()) return;
// A RW ref on the LHS (e.g.: '_[preInc(*here*)] <= _') is asking for trouble at
// this point. These should be lowered in an earlier pass into sequenced
// temporaries.
UASSERT_OBJ(!refp->access().isRW(), refp, "RW ref on LHS of NBA");
// Multiple target variables
// (e.g.: '{*here*, *and here*} <= _',or '*here*[*and here* = _] <= _').
// These should be lowered in an earlier pass into sequenced statements.
UASSERT_OBJ(!m_currNbaLhsRefp, refp, "Multiple Write refs on LHS of NBA");
// Hold on to it
m_currNbaLhsRefp = refp;
}
});
// The target variable of the NBA (there can only be one per NBA at this point)
AstVarScope* const vscp = m_currNbaLhsRefp->varScopep();