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//===- DAGISelMatcherOpt.cpp - Optimize a DAG Matcher ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the DAG Matcher optimizer.
//
//===----------------------------------------------------------------------===//
#include "DAGISelMatcher.h"
using namespace llvm;
static void ContractNodes(OwningPtr<MatcherNode> &Matcher) {
// If we reached the end of the chain, we're done.
MatcherNode *N = Matcher.get();
if (N == 0) return;
// If we have a push node, walk down both edges.
if (PushMatcherNode *Push = dyn_cast<PushMatcherNode>(N))
ContractNodes(Push->getFailurePtr());
// If we found a movechild node with a node that comes in a 'foochild' form,
// transform it.
if (MoveChildMatcherNode *MC = dyn_cast<MoveChildMatcherNode>(N)) {
if (RecordMatcherNode *RM = dyn_cast<RecordMatcherNode>(MC->getNext())) {
MatcherNode *New
= new RecordChildMatcherNode(MC->getChildNo(), RM->getWhatFor());
New->setNext(Matcher.take());
Matcher.reset(New);
MC->setNext(RM->takeNext());
return ContractNodes(Matcher);
}
}
if (MoveChildMatcherNode *MC = dyn_cast<MoveChildMatcherNode>(N))
if (MoveParentMatcherNode *MP =
dyn_cast<MoveParentMatcherNode>(MC->getNext())) {
Matcher.reset(MP->takeNext());
return ContractNodes(Matcher);
}
ContractNodes(N->getNextPtr());
}
MatcherNode *llvm::OptimizeMatcher(MatcherNode *Matcher) {
OwningPtr<MatcherNode> MatcherPtr(Matcher);
ContractNodes(MatcherPtr);
return MatcherPtr.take();
}
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