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
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index ac29de6..e902688 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -78,7 +78,7 @@
/// 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 llvm::DeleteDeadPHIs(BasicBlock *BB) {
+bool llvm::DeleteDeadPHIs(BasicBlock *BB) {
// Recursively deleting a PHI may cause multiple PHIs to be deleted
// or RAUW'd undef, so use an array of WeakVH for the PHIs to delete.
SmallVector<WeakVH, 8> PHIs;
@@ -86,9 +86,12 @@
PHINode *PN = dyn_cast<PHINode>(I); ++I)
PHIs.push_back(PN);
+ bool Changed = false;
for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
if (PHINode *PN = dyn_cast_or_null<PHINode>(PHIs[i].operator Value*()))
- RecursivelyDeleteDeadPHINode(PN);
+ Changed |= RecursivelyDeleteDeadPHINode(PN);
+
+ return Changed;
}
/// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,