Re-apply 70645, converting ScalarEvolution to use

CallbackVH, with fixes. allUsesReplacedWith need to
walk the def-use chains and invalidate all users of a
value that is replaced. SCEVs of users need to be
recalcualted even if the new value is equivalent. Also,
make forgetLoopPHIs walk def-use chains, since any
SCEV that depends on a PHI should be recalculated when
more information about that PHI becomes available.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70927 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 29 deletions

diff --git a/include/llvm/Transforms/Utils/BasicBlockUtils.h b/include/llvm/Transforms/Utils/BasicBlockUtils.h
index 367e4b4..95ffa46 100644
--- a/include/llvm/Transforms/Utils/BasicBlockUtils.h
+++ b/include/llvm/Transforms/Utils/BasicBlockUtils.h
@@ -25,7 +25,6 @@ namespace llvm {
 class Instruction;
 class Pass;
 class AliasAnalysis;
-class ValueDeletionListener;
 
 /// DeleteDeadBlock - Delete the specified block, which must have no
 /// predecessors.
@@ -41,9 +40,8 @@ void FoldSingleEntryPHINodes(BasicBlock *BB);
 /// DeleteDeadPHIs - Examine each PHI in the given block and delete it if it
 /// is dead. Also recursively delete any operands that become dead as
 /// a result. This includes tracing the def-use list from the PHI to see if
-/// it is ultimately unused or if it reaches an unused cycle.  If a
-/// ValueDeletionListener is specified, it is notified of the deletions.
-void DeleteDeadPHIs(BasicBlock *BB, ValueDeletionListener *VDL = 0);
+/// it is ultimately unused or if it reaches an unused cycle.
+void DeleteDeadPHIs(BasicBlock *BB);
 
 /// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,
 /// if possible.  The return value indicates success or failure.
diff --git a/include/llvm/Transforms/Utils/Local.h b/include/llvm/Transforms/Utils/Local.h
index 4cb46b0..5ea1a50 100644
--- a/include/llvm/Transforms/Utils/Local.h
+++ b/include/llvm/Transforms/Utils/Local.h
@@ -50,40 +50,17 @@ bool ConstantFoldTerminator(BasicBlock *BB);
 ///
 bool isInstructionTriviallyDead(Instruction *I);
 
-/// ValueDeletionListener - A simple abstract interface for delivering
-/// notifications when Values are deleted.
-///
-/// @todo Consider whether ValueDeletionListener can be made obsolete by
-///       requiring clients to use CallbackVH instead.
-class ValueDeletionListener {
-public:
-  /// ValueWillBeDeleted - This method is called shortly before the specified
-  /// value will be deleted.
-  virtual void ValueWillBeDeleted(Value *V) = 0;
-
-protected:
-  virtual ~ValueDeletionListener();
-};
-
 /// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a
 /// trivially dead instruction, delete it.  If that makes any of its operands
 /// trivially dead, delete them too, recursively.
-///
-/// If a ValueDeletionListener is specified, it is notified of instructions that
-/// are actually deleted (before they are actually deleted).
-void RecursivelyDeleteTriviallyDeadInstructions(Value *V,
-                                                ValueDeletionListener *VDL = 0);
+void RecursivelyDeleteTriviallyDeadInstructions(Value *V);
 
 /// RecursivelyDeleteDeadPHINode - If the specified value is an effectively
 /// dead PHI node, due to being a def-use chain of single-use nodes that
 /// either forms a cycle or is terminated by a trivially dead instruction,
 /// delete it.  If that makes any of its operands trivially dead, delete them
 /// too, recursively.
-///
-/// If a ValueDeletionListener is specified, it is notified of instructions that
-/// are actually deleted (before they are actually deleted).
-void RecursivelyDeleteDeadPHINode(PHINode *PN,
-                                  ValueDeletionListener *VDL = 0);
+void RecursivelyDeleteDeadPHINode(PHINode *PN);
 
 //===----------------------------------------------------------------------===//
 //  Control Flow Graph Restructuring.