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Add AstNode::foreach method for simple pre-order traversal (#3276)

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This commit is contained in:
Geza Lore
2022-01-09 22:34:10 +00:00
committed by GitHub
parent 50094ca296
commit 64a6e1ac8b
15 changed files with 207 additions and 317 deletions
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src/V3Premit.cpp
+12 -48
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@@ -37,52 +37,6 @@
constexpr int STATIC_CONST_MIN_WIDTH = 256; // Minimum size to extract to static constant
//######################################################################
// Structure for global state
class PremitAssignVisitor final : public VNVisitor {
private:
// NODE STATE
// AstVar::user3() // bool; occurs on LHS of current assignment
const VNUser3InUse m_inuser3;
// STATE
bool m_noopt = false; // Disable optimization of variables in this block
// METHODS
VL_DEBUG_FUNC; // Declare debug()
// VISITORS
virtual void visit(AstNodeAssign* nodep) override {
// AstNode::user3ClearTree(); // Implied by VNUser3InUse
// LHS first as fewer varrefs
iterateAndNextNull(nodep->lhsp());
// Now find vars marked as lhs
iterateAndNextNull(nodep->rhsp());
}
virtual void visit(AstVarRef* nodep) override {
// it's LHS var is used so need a deep temporary
if (nodep->access().isWriteOrRW()) {
nodep->varp()->user3(true);
} else {
if (nodep->varp()->user3()) {
if (!m_noopt) UINFO(4, "Block has LHS+RHS var: " << nodep << endl);
m_noopt = true;
}
}
}
virtual void visit(AstNode* nodep) override { iterateChildren(nodep); }
public:
// CONSTRUCTORS
explicit PremitAssignVisitor(AstNodeAssign* nodep) {
UINFO(4, " PremitAssignVisitor on " << nodep << endl);
iterate(nodep);
}
virtual ~PremitAssignVisitor() override = default;
bool noOpt() const { return m_noopt; }
};
//######################################################################
// Premit state, as a visitor of each AstNode
@@ -92,7 +46,7 @@ private:
// AstNodeMath::user() -> bool. True if iterated already
// AstShiftL::user2() -> bool. True if converted to conditional
// AstShiftR::user2() -> bool. True if converted to conditional
// *::user3() -> See PremitAssignVisitor
// *::user3() -> Used when visiting AstNodeAssign
const VNUser1InUse m_inuser1;
const VNUser2InUse m_inuser2;
@@ -231,7 +185,17 @@ private:
virtual void visit(AstNodeAssign* nodep) override {
startStatement(nodep);
{
const bool noopt = PremitAssignVisitor(nodep).noOpt();
bool noopt = false;
{
const VNUser3InUse user3InUse;
nodep->lhsp()->foreach<AstVarRef>([](const AstVarRef* refp) {
if (refp->access().isWriteOrRW()) refp->varp()->user3(true);
});
nodep->rhsp()->foreach<AstVarRef>([&noopt](const AstVarRef* refp) {
if (refp->access().isReadOnly() && refp->varp()->user3()) noopt = true;
});
}
if (noopt && !nodep->user1()) {
nodep->user1(true);
// Need to do this even if not wide, as e.g. a select may be on a wide operator