utils/TableGen/DAGISelMatcherOpt.cpp

   1 //===- DAGISelMatcherOpt.cpp - Optimize a DAG Matcher ---------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the DAG Matcher optimizer.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "DAGISelMatcher.h"
  15 using namespace llvm;
  16
  17
  18 static void FormRecordChildNodes(OwningPtr<MatcherNode> &Matcher) {
  19   // If we reached the end of the chain, we're done.
  20   MatcherNode *N = Matcher.get();
  21   if (N == 0) return;
  22
  23   // If we have a push node, walk down both edges.
  24   if (PushMatcherNode *Push = dyn_cast<PushMatcherNode>(N))
  25     FormRecordChildNodes(Push->getFailurePtr());
  26
  27   // If we found a movechild node, check to see if our pattern matches.
  28   if (MoveChildMatcherNode *MC = dyn_cast<MoveChildMatcherNode>(N)) {
  29     if (RecordMatcherNode *RM = dyn_cast<RecordMatcherNode>(MC->getNext()))
  30       if (MoveParentMatcherNode *MP =
  31                  dyn_cast<MoveParentMatcherNode>(RM->getNext())) {
  32         MatcherNode *New
  33           = new RecordChildMatcherNode(MC->getChildNo(), RM->getWhatFor());
  34         New->setNext(MP->takeNext());
  35         Matcher.reset(New);
  36         return FormRecordChildNodes(Matcher);
  37       }
  38   }
  39
  40   FormRecordChildNodes(N->getNextPtr());
  41 }
  42
  43
  44 MatcherNode *llvm::OptimizeMatcher(MatcherNode *Matcher) {
  45   OwningPtr<MatcherNode> MatcherPtr(Matcher);
  46   FormRecordChildNodes(MatcherPtr);
  47   return MatcherPtr.take();
  48 }