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Fix invalid conditional merging when starting at 'c = c ? a : b'

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Fixes #3409.
This commit is contained in:
Geza Lore
2022-05-17 18:36:40 +01:00
parent e018eb7bac
commit 1a056f6db9
3 changed files with 139 additions and 9 deletions
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src/V3MergeCond.cpp
+17 -9
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@@ -382,15 +382,24 @@ private:
return false;
}
void addToList(AstNode* nodep, AstNode* condp, int line) {
bool addToList(AstNode* nodep, AstNode* condp, int line) {
// Set up head of new list if node is first in list
if (!m_mgFirstp) {
UASSERT_OBJ(condp, nodep, "Cannot start new list without condition " << line);
// Mark variable references in the condition
condp->foreach<AstVarRef>([](const AstVarRef* nodep) { nodep->varp()->user1(1); });
// Now check again if mergeable. We need this to pick up assignments to conditions,
// e.g.: 'c = c ? a : b' at the beginning of the list, which is in fact not mergeable
// because it updates the condition. We simply bail on these.
if (m_checkMergeable(nodep) != Mergeable::YES) {
// Clear marked variables
AstNode::user1ClearTree();
// We did not add to the list
return false;
}
m_mgFirstp = nodep;
m_mgCondp = condp;
m_listLenght = 0;
// Mark variable references in the condition
condp->foreach<AstVarRef>([](const AstVarRef* nodep) { nodep->varp()->user1(1); });
// Add any preceding nodes to the list that would allow us to extend the merge range
for (;;) {
AstNode* const backp = m_mgFirstp->backp();
@@ -416,6 +425,8 @@ private:
m_mgNextp = nodep->nextp();
// If last under parent, done with current list
if (!m_mgNextp) mergeEnd(__LINE__);
// We did add to the list
return true;
}
// If this node is the next expected node and is helpful to add to the list, do so,
@@ -424,13 +435,10 @@ private:
UASSERT_OBJ(m_mgFirstp, nodep, "List must be open");
if (m_mgNextp == nodep) {
if (isSimplifiableNode(nodep)) {
addToList(nodep, nullptr, __LINE__);
return true;
}
if (isCheapNode(nodep)) {
if (addToList(nodep, nullptr, __LINE__)) return true;
} else if (isCheapNode(nodep)) {
nodep->user2(1);
addToList(nodep, nullptr, __LINE__);
return true;
if (addToList(nodep, nullptr, __LINE__)) return true;
}
}
// Not added to list, so we are done with the current list