From 3ef437d137afe7409b93310a2092a2f8a8dbfcca Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 11 Oct 2007 04:18:11 +0000
Subject: [PATCH] Add a new use_iterator::atEnd() method, which allows us to
 shrink pred_iterator down to a single ivar.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42859 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/CFG.h | 11 +++++------
 include/llvm/Use.h         |  3 +++
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/llvm/Support/CFG.h b/include/llvm/Support/CFG.h
index 4efefa72531..a2cc22c910d 100644
--- a/include/llvm/Support/CFG.h
+++ b/include/llvm/Support/CFG.h
@@ -29,7 +29,6 @@ namespace llvm {
 template <class _Ptr,  class _USE_iterator> // Predecessor Iterator
 class PredIterator : public forward_iterator<_Ptr, ptrdiff_t> {
   typedef forward_iterator<_Ptr, ptrdiff_t> super;
-  _Ptr *BB;
   _USE_iterator It;
 public:
   typedef PredIterator<_Ptr,_USE_iterator> _Self;
@@ -37,26 +36,26 @@ public:
 
   inline void advancePastNonTerminators() {
     // Loop to ignore non terminator uses (for example PHI nodes)...
-    while (It != BB->use_end() && !isa<TerminatorInst>(*It))
+    while (!It.atEnd() && !isa<TerminatorInst>(*It))
       ++It;
   }
 
-  inline PredIterator(_Ptr *bb) : BB(bb), It(bb->use_begin()) {
+  inline PredIterator(_Ptr *bb) : It(bb->use_begin()) {
     advancePastNonTerminators();
   }
-  inline PredIterator(_Ptr *bb, bool) : BB(bb), It(bb->use_end()) {}
+  inline PredIterator(_Ptr *bb, bool) : It(bb->use_end()) {}
 
   inline bool operator==(const _Self& x) const { return It == x.It; }
   inline bool operator!=(const _Self& x) const { return !operator==(x); }
 
   inline pointer operator*() const {
-    assert(It != BB->use_end() && "pred_iterator out of range!");
+    assert(!It.atEnd() && "pred_iterator out of range!");
     return cast<TerminatorInst>(*It)->getParent();
   }
   inline pointer *operator->() const { return &(operator*()); }
 
   inline _Self& operator++() {   // Preincrement
-    assert(It != BB->use_end() && "pred_iterator out of range!");
+    assert(!It.atEnd() && "pred_iterator out of range!");
     ++It; advancePastNonTerminators();
     return *this;
   }
diff --git a/include/llvm/Use.h b/include/llvm/Use.h
index c88d41f7005..ce13648f9b8 100644
--- a/include/llvm/Use.h
+++ b/include/llvm/Use.h
@@ -120,6 +120,9 @@ public:
   bool operator!=(const _Self &x) const {
     return !operator==(x);
   }
+  
+  /// atEnd - return true if this iterator is equal to use_end() on the value.
+  bool atEnd() const { return U == 0; }
 
   // Iterator traversal: forward iteration only
   _Self &operator++() {          // Preincrement