diff --git a/renderdoc/driver/shaders/dxil/dxil_bytecode.h b/renderdoc/driver/shaders/dxil/dxil_bytecode.h
index b45a60b70..e788f031e 100644
--- a/renderdoc/driver/shaders/dxil/dxil_bytecode.h
+++ b/renderdoc/driver/shaders/dxil/dxil_bytecode.h
@@ -658,7 +658,7 @@ struct Constant : public ForwardReferencableValue<Constant>
     if(flags & 0x10)
       return u32;
     // silently return 0 for NULL/Undef constants
-    if(flags & 0x06)
+    if(flags & 0x03)
       return 0U;
     RDCERR("Wrong type of constant being accessed");
     return 0U;
@@ -669,7 +669,7 @@ struct Constant : public ForwardReferencableValue<Constant>
     if(flags & 0x10)
       return u64;
     // silently return 0 for NULL/Undef constants
-    if(flags & 0x06)
+    if(flags & 0x03)
       return 0U;
     RDCERR("Wrong type of constant being accessed");
     return 0U;
@@ -680,7 +680,7 @@ struct Constant : public ForwardReferencableValue<Constant>
     if(flags & 0x10)
       return s64;
     // silently return 0 for NULL/Undef constants
-    if(flags & 0x06)
+    if(flags & 0x03)
       return 0;
     RDCERR("Wrong type of constant being accessed");
     return 0U;
diff --git a/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp b/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp
index 392fae2f4..9353b3ec8 100644
--- a/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp
+++ b/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp
@@ -1875,7 +1875,10 @@ rdcstr Constant::toString(bool withType) const
         ret += ", ";
       if(withType)
         ret += type->inner->toString() + " ";
-      shaderValAppendToString(type, v, i, ret);
+      if(isCompound() && cast<Constant>(members->at(i))->isUndef())
+        ret += "undef";
+      else
+        shaderValAppendToString(type, v, i, ret);
     }
     ret += ">";
   }