LoopInfo: Simplify ownership of Loop objects

[oota-llvm.git] / include / llvm / Analysis / LoopInfo.h

diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 616d6ad1761a7aa93925a1024de495c135eafeec..a2bd6574e615b585ab5a0a350d76e0df7752bf22 100644 (file)
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -73,6 +73,9 @@ class LoopBase {
 
   SmallPtrSet<const BlockT*, 8> DenseBlockSet;
 
+  /// Indicator that this loop is no longer a valid loop.
+  bool IsInvalid = false;
+
   LoopBase(const LoopBase<BlockT, LoopT> &) = delete;
   const LoopBase<BlockT, LoopT>&
     operator=(const LoopBase<BlockT, LoopT> &) = delete;
@@ -150,6 +153,12 @@ public:
     return Blocks.size();
   }
 
+  /// Invalidate the loop, indicating that it is no longer a loop.
+  void invalidate() { IsInvalid = true; }
+
+  /// Return true if this loop is no longer valid.
+  bool isInvalid() { return IsInvalid; }
+
   /// isLoopExiting - True if terminator in the block can branch to another
   /// block that is outside of the current loop.
   ///
@@ -402,6 +411,9 @@ public:
   /// isLCSSAForm - Return true if the Loop is in LCSSA form
   bool isLCSSAForm(DominatorTree &DT) const;
 
+  /// \brief Return true if this Loop and all inner subloops are in LCSSA form.
+  bool isRecursivelyLCSSAForm(DominatorTree &DT) const;
+
   /// isLoopSimplifyForm - Return true if the Loop is in the form that
   /// the LoopSimplify form transforms loops to, which is sometimes called
   /// normal form.
@@ -493,6 +505,8 @@ class LoopInfoBase {
   // BBMap - Mapping of basic blocks to the inner most loop they occur in
   DenseMap<const BlockT *, LoopT *> BBMap;
   std::vector<LoopT *> TopLevelLoops;
+  std::vector<LoopT *> RemovedLoops;
+
   friend class LoopBase<BlockT, LoopT>;
   friend class LoopInfo;
 
@@ -524,6 +538,9 @@ public:
     for (auto *L : TopLevelLoops)
       delete L;
     TopLevelLoops.clear();
+    for (auto *L : RemovedLoops)
+      delete L;
+    RemovedLoops.clear();
   }
 
   /// iterator/begin/end - The interface to the top-level loops in the current
@@ -656,11 +673,11 @@ public:
 
   // Most of the public interface is provided via LoopInfoBase.
 
-  /// updateUnloop - Update LoopInfo after removing the last backedge from a
-  /// loop--now the "unloop". This updates the loop forest and parent loops for
-  /// each block so that Unloop is no longer referenced, but the caller must
-  /// actually delete the Unloop object.
-  void updateUnloop(Loop *Unloop);
+  /// Update LoopInfo after removing the last backedge from a loop. This updates
+  /// the loop forest and parent loops for each block so that \c L is no longer
+  /// referenced, but does not actually delete \c L immediately. The pointer
+  /// will remain valid until this LoopInfo's memory is released.
+  void markAsRemoved(Loop *L);
 
   /// replacementPreservesLCSSAForm - Returns true if replacing From with To
   /// everywhere is guaranteed to preserve LCSSA form.