From 48aa5756a29a7b96850ac646d1edd806c9df4643 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 7 Mar 2010 06:29:26 +0000
Subject: [PATCH] add some helper functions and implement isContradictory for
 CheckValueTypeMatcher.  The isContradictory implementation helps us factor
 better, shrinking x86 table from 79144 -> 78896 bytes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97905 91177308-0d34-0410-b5e6-96231b3b80d8
---
 utils/TableGen/DAGISelMatcher.cpp | 55 +++++++++++++++++++++++++++++++
 utils/TableGen/DAGISelMatcher.h   | 44 +++++++++++++++++++++++++
 2 files changed, 99 insertions(+)

diff --git a/utils/TableGen/DAGISelMatcher.cpp b/utils/TableGen/DAGISelMatcher.cpp
index c4f1cbfcf05..22d2fe84809 100644
--- a/utils/TableGen/DAGISelMatcher.cpp
+++ b/utils/TableGen/DAGISelMatcher.cpp
@@ -29,6 +29,54 @@ void Matcher::printOne(raw_ostream &OS) const {
   printImpl(OS, 0);
 }
 
+/// unlinkNode - Unlink the specified node from this chain.  If Other == this,
+/// we unlink the next pointer and return it.  Otherwise we unlink Other from
+/// the list and return this.
+Matcher *Matcher::unlinkNode(Matcher *Other) {
+  if (this == Other)
+    return takeNext();
+ 
+  // Scan until we find the predecessor of Other.
+  Matcher *Cur = this;
+  for (; Cur && Cur->getNext() != Other; Cur = Cur->getNext())
+    /*empty*/;
+
+  if (Cur == 0) return 0;
+  Cur->takeNext();
+  Cur->setNext(Other->takeNext());
+  return this;
+}
+
+/// canMoveBefore - Return true if this matcher is the same as Other, or if
+/// we can move this matcher past all of the nodes in-between Other and this
+/// node.  Other must be equal to or before this.
+bool Matcher::canMoveBefore(const Matcher *Other) const {
+  for (;; Other = Other->getNext()) {
+    assert(Other && "Other didn't come before 'this'?");
+    if (this == Other) return true;
+
+    // We have to be able to move this node across the Other node.
+    if (!canMoveBeforeNode(Other))
+      return false;
+  }
+}
+
+/// canMoveBefore - Return true if it is safe to move the current matcher
+/// across the specified one.
+bool Matcher::canMoveBeforeNode(const Matcher *Other) const {
+  // We can move simple predicates before record nodes.
+  if (isSimplePredicateNode())
+    return Other->isSimplePredicateOrRecordNode();
+  
+  // We can move record nodes across simple predicates.
+  if (isSimplePredicateOrRecordNode())
+    return isSimplePredicateNode();
+  
+  // We can't move record nodes across each other etc.
+  return false;
+}
+
+
 ScopeMatcher::~ScopeMatcher() {
   for (unsigned i = 0, e = Children.size(); i != e; ++i)
     delete Children[i];
@@ -345,3 +393,10 @@ bool CheckIntegerMatcher::isContradictoryImpl(const Matcher *M) const {
     return CIM->getValue() != getValue();
   return false;
 }
+
+bool CheckValueTypeMatcher::isContradictoryImpl(const Matcher *M) const {
+  if (const CheckValueTypeMatcher *CVT = dyn_cast<CheckValueTypeMatcher>(M))
+    return CVT->getTypeName() != getTypeName();
+  return false;
+}
+
diff --git a/utils/TableGen/DAGISelMatcher.h b/utils/TableGen/DAGISelMatcher.h
index 7955c7e2630..ef7ecf40050 100644
--- a/utils/TableGen/DAGISelMatcher.h
+++ b/utils/TableGen/DAGISelMatcher.h
@@ -113,6 +113,49 @@ public:
     return false;
   }
   
+  /// isSimplePredicateNode - Return true if this is a simple predicate that
+  /// operates on the node or its children without potential side effects or a
+  /// change of the current node.
+  bool isSimplePredicateNode() const {
+    switch (getKind()) {
+    default: return false;
+    case CheckSame:
+    case CheckPatternPredicate:
+    case CheckPredicate:
+    case CheckOpcode:
+    case CheckType:
+    case CheckChildType:
+    case CheckInteger:
+    case CheckCondCode:
+    case CheckValueType:
+    case CheckAndImm:
+    case CheckOrImm:
+    case CheckFoldableChainNode:
+      return true;
+    }
+  }
+  
+  /// isSimplePredicateOrRecordNode - Return true if this is a record node or
+  /// a simple predicate.
+  bool isSimplePredicateOrRecordNode() const {
+    return isSimplePredicateNode() ||
+           getKind() == RecordNode || getKind() == RecordChild;
+  }
+  
+  /// unlinkNode - Unlink the specified node from this chain.  If Other == this,
+  /// we unlink the next pointer and return it.  Otherwise we unlink Other from
+  /// the list and return this.
+  Matcher *unlinkNode(Matcher *Other);
+  
+  /// canMoveBefore - Return true if this matcher is the same as Other, or if
+  /// we can move this matcher past all of the nodes in-between Other and this
+  /// node.  Other must be equal to or before this.
+  bool canMoveBefore(const Matcher *Other) const;
+  
+  /// canMoveBefore - Return true if it is safe to move the current matcher
+  /// across the specified one.
+  bool canMoveBeforeNode(const Matcher *Other) const;
+  
   /// isContradictory - Return true of these two matchers could never match on
   /// the same node.
   bool isContradictory(const Matcher *Other) const {
@@ -601,6 +644,7 @@ private:
     return cast<CheckValueTypeMatcher>(M)->TypeName == TypeName;
   }
   virtual unsigned getHashImpl() const;
+  bool isContradictoryImpl(const Matcher *M) const;
 };
   
   
-- 
2.34.1