Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -575,12 +575,12 @@
   }
 
   if (Checks.size() > 0) {
+    // Make sure we're not losing information. Alignment needs to be a power of 2
+    assert(!AlignVal || (uint64_t)1 << llvm::Log2_64(AlignVal) == AlignVal);
     llvm::Constant *StaticData[] = {
-     EmitCheckSourceLocation(Loc),
-      EmitCheckTypeDescriptor(Ty),
-      llvm::ConstantInt::get(SizeTy, AlignVal),
-      llvm::ConstantInt::get(Int8Ty, TCK)
-    };
+        EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty),
+        llvm::ConstantInt::get(Int8Ty, llvm::Log2_64(AlignVal)),
+        llvm::ConstantInt::get(Int8Ty, TCK)};
     EmitCheck(Checks, "type_mismatch", StaticData, Ptr);
   }