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Do not defer deletion in const-bit-op-tree

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Deferring deletion of unused terms is not necessary, but can cause huge
memory usage increases in some bad cases.
This commit is contained in:
Geza Lore 2024-03-11 17:07:19 +00:00
parent ba47da6587
commit c92ced4ac7
1 changed files with 5 additions and 7 deletions
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12
src/V3Const.cpp
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@ -684,7 +684,7 @@ public:
// Reduction ops are transformed in the same way.
// &{v[0], v[1]} => 2'b11 == (2'b11 & v)
static AstNodeExpr* simplify(AstNodeExpr* nodep, int resultWidth, unsigned externalOps,
VDouble0& reduction, VNDeleter& deleterr) {
VDouble0& reduction) {
UASSERT_OBJ(1 <= resultWidth && resultWidth <= 64, nodep, "resultWidth out of range");
// Walk tree, gathering all terms referenced in expression
@ -727,7 +727,7 @@ public:
}
// Set width and widthMin precisely
resultp->dtypeChgWidth(resultWidth, 1);
for (AstNode* const termp : termps) deleterr.pushDeletep(termp);
for (AstNode* const termp : termps) VL_DO_DANGLING(termp->deleteTree(), termp);
return resultp;
}
const ResultTerm result = v->getResultTerm();
@ -803,7 +803,7 @@ public:
// Only substitute the result if beneficial as determined by operation count
if (visitor.m_ops <= resultOps) {
for (AstNode* const termp : termps) deleterr.pushDeletep(termp);
for (AstNode* const termp : termps) VL_DO_DANGLING(termp->deleteTree(), termp);
return nullptr;
}
@ -1187,11 +1187,9 @@ class ConstVisitor final : public VNVisitor {
const AstAnd* const andp = VN_CAST(nodep, And);
const int width = nodep->width();
if (andp && isConst(andp->lhsp(), 1)) { // 1 & BitOpTree
newp = ConstBitOpTreeVisitor::simplify(andp->rhsp(), width, 1, m_statBitOpReduction,
deleter());
newp = ConstBitOpTreeVisitor::simplify(andp->rhsp(), width, 1, m_statBitOpReduction);
} else { // BitOpTree
newp = ConstBitOpTreeVisitor::simplify(nodep, width, 0, m_statBitOpReduction,
deleter());
newp = ConstBitOpTreeVisitor::simplify(nodep, width, 0, m_statBitOpReduction);
}
if (newp) {