Index: lib/CodeGen/LoopGenerators.cpp
===================================================================
--- lib/CodeGen/LoopGenerators.cpp
+++ lib/CodeGen/LoopGenerators.cpp
@@ -172,6 +172,11 @@
   Builder.CreateCall(SubFn, SubFnParam);
   createCallJoinThreads();
 
+  // Mark the end of the lifetime for the parameter struct
+  Type *Ty = Struct->getType();
+  ConstantInt *SizeOf = dyn_cast<ConstantInt>(ConstantExpr::getSizeOf(Ty));
+  Builder.CreateLifetimeEnd(Struct, SizeOf);
+
   return IV;
 }
 
@@ -280,9 +285,22 @@
   for (Value *V : Values)
     Members.push_back(V->getType());
 
+  // We do not want to allocate the alloca inside any loop, thus we allocate it
+  // in the entry block of the function and use annotations to denote the actual
+  // live span (similar to clang).
+  //
+  // XXX: It might be necessary to allocate the struct explicitly in front of
+  //      the outermost loop surrounding the current insertion block in order
+  //      to prevent us from allocating stack space without actually using it.
+  //      For now we assume the annotations suffice to sink the allocas to the
+  //      most recent dominating basic block which is not part of a loop.
+  BasicBlock &EntryBB = Builder.GetInsertBlock()->getParent()->getEntryBlock();
+  Instruction *IP = EntryBB.getFirstInsertionPt();
   StructType *Ty = StructType::get(Builder.getContext(), Members);
-  Value *Struct =
-      new AllocaInst(Ty, 0, "polly.par.userContext", Builder.GetInsertPoint());
+  Value *Struct = new AllocaInst(Ty, 0, "polly.par.userContext", IP);
+
+  ConstantInt *SizeOf = dyn_cast<ConstantInt>(ConstantExpr::getSizeOf(Ty));
+  Builder.CreateLifetimeStart(Struct, SizeOf);
 
   for (unsigned i = 0; i < Values.size(); i++) {
     Value *Address = Builder.CreateStructGEP(Struct, i);