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.

llvm-svn: 121170

1 files changed, 4 insertions, 13 deletions

diff --git a/llvm/lib/VMCore/Function.cpp b/llvm/lib/VMCore/Function.cpp
index 22f0096e538..00d1d787324 100644
--- a/llvm/lib/VMCore/Function.cpp
+++ b/llvm/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) {