[CodeGen] Don't attempt a tail-call with implicit sret.
Tailcalls are only OK with forwarded sret pointers. With sret demotion,
they're not, as we'd have a pointer into a soon-to-be-dead stack frame.
Differential Revison: http://reviews.llvm.org/D8510
llvm-svn: 233409
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 6a08fff..67ab548 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -7193,6 +7193,10 @@
Entry.Alignment = Align;
CLI.getArgs().insert(CLI.getArgs().begin(), Entry);
CLI.RetTy = Type::getVoidTy(CLI.RetTy->getContext());
+
+ // sret demotion isn't compatible with tail-calls, since the sret argument
+ // points into the callers stack frame.
+ CLI.IsTailCall = false;
} else {
for (unsigned I = 0, E = RetTys.size(); I != E; ++I) {
EVT VT = RetTys[I];