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Internals: Clean up V3Branch (#6505) 

No functional change
This commit is contained in:
Geza Lore 2025-09-29 15:51:37 +02:00 committed by GitHub
parent 83f4db956b
commit 5c72b45975
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GPG Key ID: B5690EEEBB952194
1 changed files with 24 additions and 63 deletions
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87
src/V3Branch.cpp
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@ -33,85 +33,45 @@ VL_DEFINE_DEBUG_FUNCTIONS;
// Branch state, as a visitor of each AstNode
class BranchVisitor final : public VNVisitorConst {
// NODE STATE
// Entire netlist:
// AstFTask::user1() -> int. Number of references
const VNUser1InUse m_inuser1;
// STATE - across all visitors
std::vector<AstCFunc*> m_cfuncsp; // List of all tasks
// STATE - for current visit position (use VL_RESTORER)
int m_likely = false; // Excuses for branch likely taken
int m_unlikely = false; // Excuses for branch likely not taken
// METHODS
void reset() {
m_likely = false;
m_unlikely = false;
}
void checkUnlikely(const AstNode* nodep) {
if (nodep->isUnlikely()) {
UINFO(4, " UNLIKELY: " << nodep);
m_unlikely++;
}
}
int m_unlikely = 0; // Excuses for branch likely not taken
// VISITORS
void visit(AstNodeIf* nodep) override {
UINFO(4, " IF: " << nodep);
VL_RESTORER(m_likely);
VL_RESTORER(m_unlikely);
{
// Do if
reset();
iterateAndNextConstNull(nodep->thensp());
const int ifLikely = m_likely;
const int ifUnlikely = m_unlikely;
// Do else
reset();
iterateAndNextConstNull(nodep->elsesp());
const int elseLikely = m_likely;
const int elseUnlikely = m_unlikely;
// Compute
const int likeness = ifLikely - ifUnlikely - (elseLikely - elseUnlikely);
if (likeness > 0) {
nodep->branchPred(VBranchPred::BP_LIKELY);
} else if (likeness < 0) {
nodep->branchPred(VBranchPred::BP_UNLIKELY);
} // else leave unknown
}
}
void visit(AstNodeCCall* nodep) override {
checkUnlikely(nodep);
nodep->funcp()->user1Inc();
iterateChildrenConst(nodep);
// Do then
m_unlikely = 0;
iterateAndNextConstNull(nodep->thensp());
const int thenUnlikely = m_unlikely;
// Do else
m_unlikely = 0;
iterateAndNextConstNull(nodep->elsesp());
const int elseUnlikely = m_unlikely;
// Compute
if (elseUnlikely > thenUnlikely) {
nodep->branchPred(VBranchPred::BP_LIKELY);
} else if (elseUnlikely < thenUnlikely) {
nodep->branchPred(VBranchPred::BP_UNLIKELY);
} // else leave unknown
}
void visit(AstCFunc* nodep) override {
checkUnlikely(nodep);
m_cfuncsp.push_back(nodep);
iterateChildrenConst(nodep);
}
void visit(AstNode* nodep) override {
checkUnlikely(nodep);
if (!nodep->dontInline()) nodep->isInline(true);
iterateChildrenConst(nodep);
}
// METHODS
void calc_tasks() {
for (AstCFunc* nodep : m_cfuncsp) {
if (!nodep->dontInline()) nodep->isInline(true);
void visit(AstNode* nodep) override {
if (nodep->isUnlikely()) {
UINFO(4, " UNLIKELY: " << nodep);
++m_unlikely;
}
iterateChildrenConst(nodep);
}
public:
// CONSTRUCTORS
explicit BranchVisitor(AstNetlist* nodep) {
reset();
iterateChildrenConst(nodep);
calc_tasks();
}
explicit BranchVisitor(AstNetlist* nodep) { iterateChildrenConst(nodep); }
~BranchVisitor() override = default;
};
@ -121,4 +81,5 @@ public:
void V3Branch::branchAll(AstNetlist* nodep) {
UINFO(2, __FUNCTION__ << ":");
{ BranchVisitor{nodep}; }
V3Global::dumpCheckGlobalTree("branch", 0, dumpTreeEitherLevel() >= 3);
}