diff --git a/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp b/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp
index 5f475dada..c4f30bad4 100644
--- a/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp
+++ b/renderdoc/driver/shaders/spirv/spirv_disassemble.cpp
@@ -1613,7 +1613,10 @@ rdcstr Reflector::Disassemble(const rdcstr &entryPoint,
               uint32_t c = decoded.components[i];
 
               ret += idName(c < vec1Cols ? decoded.vector1 : decoded.vector2) + ".";
-              ret.push_back(comps[c < vec1Cols ? c : c - vec1Cols]);
+              if(c == ~0U)
+                ret.push_back('_');
+              else
+                ret.push_back(comps[c < vec1Cols ? c : c - vec1Cols]);
 
               if(i + 1 < decoded.components.size())
                 ret += ", ";