Initialize the cleanup.dst variable if necessary. Fixes PR3789.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67075 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index a54f9bd..441c9fc 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -549,7 +549,7 @@
EndBlock = createBasicBlock("cleanup.end");
llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
-
+
Builder.SetInsertPoint(SwitchBlock);
llvm::Value *DestCodePtr = CreateTempAlloca(llvm::Type::Int32Ty,
@@ -561,9 +561,14 @@
BranchFixups.size());
// Restore the current basic block (if any)
- if (CurBB)
+ if (CurBB) {
Builder.SetInsertPoint(CurBB);
- else
+
+ // If we had a current basic block, we also need to emit an instruction
+ // to initialize the cleanup destination.
+ Builder.CreateStore(llvm::Constant::getNullValue(llvm::Type::Int32Ty),
+ DestCodePtr);
+ } else
Builder.ClearInsertionPoint();
for (size_t i = 0, e = BranchFixups.size(); i != e; ++i) {
diff --git a/test/CodeGen/cleanup-stack.c b/test/CodeGen/cleanup-stack.c
new file mode 100644
index 0000000..360f6e7
--- /dev/null
+++ b/test/CodeGen/cleanup-stack.c
@@ -0,0 +1,15 @@
+// RUN: clang -emit-llvm %s -o %t &&
+// RUN: grep "store i32 0, i32* %cleanup" %t | count 2
+void f(int n) {
+ int a[n];
+
+ {
+ int b[n];
+
+ if (n)
+ return;
+ }
+
+ if (n)
+ return;
+}