From 06b6c587e8c51c76b85f64c3d47176bc25aafd0b Mon Sep 17 00:00:00 2001
From: Dylan Noblesmith <nobled@dreamwidth.org>
Date: Sat, 31 Dec 2011 13:58:58 +0000
Subject: [PATCH] VMCore: add assert for miscompile

See PR11652. Trying to add this assert to
setSubclassData() itself actually prevented
the miscompile entirely, so it has to be here.

This makes the source of the bug more obvious
than the other asserts triggering later on did.

llvm-svn: 147390
---
 lib/VMCore/Type.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index f4fad667a13..d19dc06caa1 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -707,7 +707,12 @@ PointerType *PointerType::get(Type *EltTy, unsigned AddressSpace) {
 
 PointerType::PointerType(Type *E, unsigned AddrSpace)
   : SequentialType(PointerTyID, E) {
+#ifndef NDEBUG
+  const unsigned oldNCT = NumContainedTys;
+#endif
   setSubclassData(AddrSpace);
+  // Check for miscompile. PR11652.
+  assert(oldNCT == NumContainedTys && "bitfield written out of bounds?");
 }
 
 PointerType *Type::getPointerTo(unsigned addrs) {