Make RecursivelyDeleteTriviallyDeadInstructions,

RecursivelyDeleteDeadPHINode, and DeleteDeadPHIs return a flag
indicating whether they made any changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92732 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Utils/BasicBlockUtils.h

@@ -40,8 +40,9 @@ 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.
-void DeleteDeadPHIs(BasicBlock *BB);
+/// it is ultimately unused or if it reaches an unused cycle. Return true
+/// if any PHIs were deleted.
+bool DeleteDeadPHIs(BasicBlock *BB);
 
 /// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,
 /// if possible.  The return value indicates success or failure.

include/llvm/Transforms/Utils/Local.h

@@ -63,15 +63,16 @@ bool isInstructionTriviallyDead(Instruction *I);
 
 /// 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.
-void RecursivelyDeleteTriviallyDeadInstructions(Value *V);
+/// trivially dead, delete them too, recursively.  Return true if any
+/// instructions were deleted.
+bool 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.
-void RecursivelyDeleteDeadPHINode(PHINode *PN);
+/// too, recursively.  Return true if the PHI node is actually deleted.
+bool RecursivelyDeleteDeadPHINode(PHINode *PN);
 
 //===----------------------------------------------------------------------===//
 //  Control Flow Graph Restructuring.