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Fix internal error on gate optimization of assign, bug1475.

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This commit is contained in:
Wilson Snyder
2019-08-03 21:49:39 -04:00
parent 9e58ede480
commit a95f58749f
7 changed files with 167 additions and 4 deletions
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src/V3Gate.cpp
+89 -3
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@@ -835,6 +835,8 @@ void GateVisitor::warnSignals() {
//######################################################################
// Push constant into expressions and reevaluate
class GateDedupeVarVisitor;
class GateElimVisitor : public GateBaseVisitor {
private:
// NODE STATE
@@ -842,6 +844,11 @@ private:
AstVarScope* m_elimVarScp; // Variable being eliminated
AstNode* m_replaceTreep; // What to replace the variable with
bool m_didReplace; // Did we do any replacements
GateDedupeVarVisitor* m_varVisp; // Callback to keep hash up to date
// METHODS
void hashReplace(AstNode* oldp, AstNode* newp);
// VISITORS
virtual void visit(AstNodeVarRef* nodep) {
if (nodep->varScopep() == m_elimVarScp) {
@@ -865,6 +872,7 @@ private:
if (VN_IS(substp, VarRef)) substp->fileline(nodep->fileline());
// Make the substp an rvalue like nodep. This facilitate the hashing in dedupe.
if (AstNodeVarRef* varrefp = VN_CAST(substp, NodeVarRef)) varrefp->lvalue(false);
hashReplace(nodep, substp);
nodep->replaceWith(substp);
nodep->deleteTree(); VL_DANGLING(nodep);
}
@@ -875,10 +883,12 @@ private:
public:
// CONSTUCTORS
virtual ~GateElimVisitor() {}
GateElimVisitor(AstNode* nodep, AstVarScope* varscp, AstNode* replaceTreep) {
GateElimVisitor(AstNode* nodep, AstVarScope* varscp, AstNode* replaceTreep,
GateDedupeVarVisitor* varVisp) {
m_didReplace = false;
m_elimVarScp = varscp;
m_replaceTreep = replaceTreep;
m_varVisp = varVisp;
iterate(nodep);
}
bool didReplace() const { return m_didReplace; }
@@ -886,7 +896,7 @@ public:
void GateVisitor::optimizeElimVar(AstVarScope* varscp, AstNode* substp, AstNode* consumerp) {
if (debug()>=5) consumerp->dumpTree(cout, "\telimUsePre: ");
GateElimVisitor elimVisitor (consumerp, varscp, substp);
GateElimVisitor elimVisitor (consumerp, varscp, substp, NULL);
if (elimVisitor.didReplace()) {
if (debug()>=9) consumerp->dumpTree(cout, "\telimUseCns: ");
//Caution: Can't let V3Const change our handle to consumerp, such as by
@@ -903,16 +913,27 @@ void GateVisitor::optimizeElimVar(AstVarScope* varscp, AstNode* substp, AstNode*
// Auxiliary hash class for GateDedupeVarVisitor
class GateDedupeHash : public V3HashedUserSame {
public:
// TYPES
typedef std::set<AstNode*> NodeSet;
private:
// NODE STATE
// Ast*::user2p -> parent AstNodeAssign* for this rhsp
// Ast*::user3p -> AstActive* of assign, for isSame() in test for duplicate
// Set to NULL if this assign's tree was later replaced
// Ast*::user5p -> AstNode* of assign if condition, for isSame() in test for duplicate
// Set to NULL if this assign's tree was later replaced
// AstUser1InUse m_inuser1; (Allocated for use in GateVisitor)
// AstUser2InUse m_inuser2; (Allocated for use in GateVisitor)
AstUser3InUse m_inuser3;
// AstUser4InUse m_inuser4; (Allocated for use in V3Hashed)
AstUser5InUse m_inuser5;
V3Hashed m_hashed; // Hash, contains rhs of assigns
NodeSet m_nodeDeleteds; // Any node in this hash was deleted
VL_DEBUG_FUNC; // Declare debug()
void hash(AstNode* nodep) {
// !NULL && the object is hashable
@@ -930,13 +951,46 @@ private:
return node1p == node2p || sameHash(node1p, node2p);
}
public:
GateDedupeHash() { }
~GateDedupeHash() {
if (v3Global.opt.debugCheck()) check();
}
// About to replace a node; any node we're tracking refers to oldp, change it to newp.
// This might be a variable on the lhs of the duplicate tree,
// or could be a rhs variable in a tree we're not replacing (or not yet anyways)
void hashReplace(AstNode* oldp, AstNode* newp) {
UINFO(9,"replacing "<<(void*)oldp<<" with "<<(void*)newp<<endl);
// We could update the user3p and user5p but the resulting node
// still has incorrect hash. We really need to remove all hash on
// the whole hash entry tree involving the replaced node and
// rehash. That's complicated and this is rare, so just remove it
// from consideration.
m_nodeDeleteds.insert(oldp);
}
bool isReplaced(AstNode* nodep) {
// Assignment may have been hashReplaced, if so consider non-match (effectively removed)
UASSERT_OBJ(!VN_IS(nodep, NodeAssign), nodep, "Dedup attempt on non-assign");
AstNode* extra1p = nodep->user3p();
AstNode* extra2p = nodep->user5p();
return ((extra1p && m_nodeDeleteds.find(extra1p) != m_nodeDeleteds.end())
|| (extra2p && m_nodeDeleteds.find(extra2p) != m_nodeDeleteds.end()));
}
// Callback from V3Hashed::findDuplicate
bool isSame(AstNode* node1p, AstNode* node2p) {
// Assignment may have been hashReplaced, if so consider non-match (effectively removed)
if (isReplaced(node1p) || isReplaced(node2p)) {
//UINFO(9, "isSame hit on replaced "<<(void*)node1p<<" "<<(void*)node2p<<endl);
return false;
}
return same(node1p->user3p(), node2p->user3p())
&& same(node1p->user5p(), node2p->user5p())
&& node1p->user2p()->type() == node2p->user2p()->type();
}
AstNodeAssign* hashAndFindDupe(AstNodeAssign* assignp, AstNode* extra1p, AstNode* extra2p) {
// Legal for extra1p/2p to be NULL, we'll compare with other assigns with extras also NULL
AstNode *rhsp = assignp->rhsp();
rhsp->user2p(assignp);
rhsp->user3p(extra1p);
@@ -954,8 +1008,26 @@ public:
m_hashed.erase(inserted);
return VN_CAST(m_hashed.iteratorNodep(dupit)->user2p(), NodeAssign);
}
// Retain new inserted information
return NULL;
}
void check() {
m_hashed.check();
for (V3Hashed::HashMmap::iterator it = m_hashed.begin(); it != m_hashed.end(); ++it) {
AstNode* nodep = it->second;
AstNode* activep = nodep->user3p();
AstNode* condVarp = nodep->user5p();
if (!isReplaced(nodep)) {
// This class won't break if activep isn't an active, or
// ifVar isn't a var, but this is checking the caller's construction.
UASSERT_OBJ(!activep || (!VN_DELETED(activep) && VN_IS(activep, Active)),
nodep, "V3Hashed check failed, lost active pointer");
UASSERT_OBJ(!condVarp || !VN_DELETED(condVarp),
nodep, "V3Hashed check failed, lost if pointer");
}
}
}
};
//######################################################################
@@ -1032,6 +1104,7 @@ public:
m_always = false;
m_dedupable = true;
}
~GateDedupeVarVisitor() { }
// PUBLIC METHODS
AstNodeVarRef* findDupe(AstNode* nodep, AstVarScope* consumerVarScopep, AstActive* activep) {
m_assignp = NULL;
@@ -1052,8 +1125,20 @@ public:
}
return NULL;
}
void hashReplace(AstNode* oldp, AstNode* newp) {
m_ghash.hashReplace(oldp, newp);
}
};
//######################################################################
void GateElimVisitor::hashReplace(AstNode* oldp, AstNode* newp) {
UINFO(9,"hashReplace "<<(void*)oldp<<" -> "<<(void*)newp<<endl);
if (m_varVisp) {
m_varVisp->hashReplace(oldp, newp);
}
}
//######################################################################
// Recurse through the graph, looking for duplicate expressions on the rhs of an assign
@@ -1093,7 +1178,7 @@ private:
GateLogicVertex* consumeVertexp
= dynamic_cast<GateLogicVertex*>(outedgep->top());
AstNode* consumerp = consumeVertexp->nodep();
GateElimVisitor elimVisitor(consumerp, vvertexp->varScp(), dupVarRefp);
GateElimVisitor elimVisitor(consumerp, vvertexp->varScp(), dupVarRefp, &m_varVisitor);
outedgep = outedgep->relinkFromp(dupVvertexp);
}
@@ -1299,6 +1384,7 @@ public:
//----------------------------------------------------------------------
void GateVisitor::mergeAssigns() {
UINFO(6, "mergeAssigns\n");
GateMergeAssignsGraphVisitor merger(&m_graph);
for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp=itp->verticesNextp()) {
if (GateVarVertex* vvertexp = dynamic_cast<GateVarVertex*>(itp)) {