Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -583,12 +583,15 @@
   }
 
   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);
+    const unsigned TypeMismatchDataVersion = 2;
     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, TypeMismatchDataVersion),
+        llvm::ConstantInt::get(Int8Ty, AlignVal ? llvm::Log2_64(AlignVal) : 1),
+        llvm::ConstantInt::get(Int8Ty, TCK)};
     EmitCheck(Checks, "type_mismatch", StaticData, Ptr);
   }
 
Index: test/CodeGen/catch-undef-behavior.c
===================================================================
--- test/CodeGen/catch-undef-behavior.c
+++ test/CodeGen/catch-undef-behavior.c
@@ -6,16 +6,16 @@
 // CHECK-UBSAN: @[[INT:.*]] = private unnamed_addr constant { i16, i16, [6 x i8] } { i16 0, i16 11, [6 x i8] c"'int'\00" }
 
 // FIXME: When we only emit each type once, use [[INT]] more below.
-// CHECK-UBSAN: @[[LINE_100:.*]] = private unnamed_addr global {{.*}}, i32 100, i32 5 {{.*}} @[[INT]], i64 4, i8 1
-// CHECK-UBSAN: @[[LINE_200:.*]] = {{.*}}, i32 200, i32 10 {{.*}}, i64 4, i8 0
+// CHECK-UBSAN: @[[LINE_100:.*]] = private unnamed_addr global {{.*}}, i32 100, i32 5 {{.*}} @[[INT]], i8 2, i8 2, i8 1
+// CHECK-UBSAN: @[[LINE_200:.*]] = {{.*}}, i32 200, i32 10 {{.*}}, i8 2, i8 2, i8 0
 // CHECK-UBSAN: @[[LINE_300:.*]] = {{.*}}, i32 300, i32 12 {{.*}} @{{.*}}, {{.*}} @{{.*}}
 // CHECK-UBSAN: @[[LINE_400:.*]] = {{.*}}, i32 400, i32 12 {{.*}} @{{.*}}, {{.*}} @{{.*}}
-// CHECK-UBSAN: @[[LINE_500:.*]] = {{.*}}, i32 500, i32 10 {{.*}} @{{.*}}, i64 4, i8 0 }
-// CHECK-UBSAN: @[[LINE_600:.*]] = {{.*}}, i32 600, i32 3 {{.*}} @{{.*}}, i64 4, i8 1 }
+// CHECK-UBSAN: @[[LINE_500:.*]] = {{.*}}, i32 500, i32 10 {{.*}} @{{.*}}, i8 2, i8 2, i8 0 }
+// CHECK-UBSAN: @[[LINE_600:.*]] = {{.*}}, i32 600, i32 3 {{.*}} @{{.*}}, i8 2, i8 2, i8 1 }
 
 // CHECK-UBSAN: @[[STRUCT_S:.*]] = private unnamed_addr constant { i16, i16, [11 x i8] } { i16 -1, i16 0, [11 x i8] c"'struct S'\00" }
 
-// CHECK-UBSAN: @[[LINE_700:.*]] = {{.*}}, i32 700, i32 14 {{.*}} @[[STRUCT_S]], i64 4, i8 3 }
+// CHECK-UBSAN: @[[LINE_700:.*]] = {{.*}}, i32 700, i32 14 {{.*}} @[[STRUCT_S]], i8 2, i8 2, i8 3 }
 // CHECK-UBSAN: @[[LINE_800:.*]] = {{.*}}, i32 800, i32 12 {{.*}} @{{.*}} }
 // CHECK-UBSAN: @[[LINE_900:.*]] = {{.*}}, i32 900, i32 11 {{.*}} @{{.*}} }
 // CHECK-UBSAN: @[[LINE_1000:.*]] = {{.*}}, i32 1000, i32 10 {{.*}} @{{.*}} }