Remove the code from Function::dropAllReferences which replaced

uses of the function's blocks with undef. This code isn't needed,
because BasicBlock's destructor handles such uses. Also, undef isn't
correct, since blockaddresses may still be used for comparisons
with null.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121170 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index 22f0096e538bf802ccdf874531a3204f9e4b41db..00d1d7873247736ca734b950449f53b38ebf9f10 100644 (file)
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -227,19 +227,10 @@ void Function::dropAllReferences() {
   for (iterator I = begin(), E = end(); I != E; ++I)
     I->dropAllReferences();
   
-  // Delete all basic blocks.
-  while (!BasicBlocks.empty()) {
-    // If there is still a reference to the block, it must be a 'blockaddress'
-    // constant pointing to it.  Just replace the BlockAddress with undef.
-    BasicBlock *BB = BasicBlocks.begin();
-    if (!BB->use_empty()) {
-      BlockAddress *BA = cast<BlockAddress>(BB->use_back());
-      BA->replaceAllUsesWith(UndefValue::get(BA->getType()));
-      BA->destroyConstant();
-    }
-    
-    BB->eraseFromParent();
-  }
+  // Delete all basic blocks. They are now unused, except possibly by
+  // blockaddresses, but BasicBlock's destructor takes care of those.
+  while (!BasicBlocks.empty())
+    BasicBlocks.begin()->eraseFromParent();
 }
 
 void Function::addAttribute(unsigned i, Attributes attr) {