When destroying a cleanup, kill any references to instructions in the entry

block before deleting it.  Fixes PR7575.

This really just a short-term fix before implementing lazy cleanups.

llvm-svn: 107676

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 306989f11e2..9375b77360c 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -688,6 +688,12 @@ static void DestroyCleanup(CodeGenFunction &CGF,
     llvm::BranchInst::Create(CGF.getUnreachableBlock(), Exit);
 
   assert(!Entry->getParent() && "cleanup entry already positioned?");
+  // We can't just delete the entry; we have to kill any references to
+  // its instructions in other blocks.
+  for (llvm::BasicBlock::iterator I = Entry->begin(), E = Entry->end();
+         I != E; ++I)
+    if (!I->use_empty())
+      I->replaceAllUsesWith(llvm::UndefValue::get(I->getType()));
   delete Entry;
 }