diff --git a/renderdoc/driver/shaders/spirv/spirv_editor.cpp b/renderdoc/driver/shaders/spirv/spirv_editor.cpp
index cbbb24f2e..845d59e53 100644
--- a/renderdoc/driver/shaders/spirv/spirv_editor.cpp
+++ b/renderdoc/driver/shaders/spirv/spirv_editor.cpp
@@ -678,6 +678,15 @@ void Editor::RegisterOp(Iter it)
     if(decorate.decoration == Decoration::BufferBlock)
       m_BufferBlockTypes.push_back(decorate.target);
   }
+  else if(opdata.op == Op::Constant)
+  {
+    if(dataTypes[opdata.resultType].IsU32())
+    {
+      uint32_t val = it.word(3);
+      if(m_U32Consts[val] == rdcspv::Id())
+        m_U32Consts[val] = opdata.result;
+    }
+  }
 }
 
 void Editor::UnregisterOp(Iter it)
@@ -740,6 +749,15 @@ void Editor::UnregisterOp(Iter it)
     if(decorate.decoration == Decoration::BufferBlock)
       m_BufferBlockTypes.removeOne(decorate.target);
   }
+  else if(opdata.op == Op::Constant)
+  {
+    if(dataTypes[opdata.resultType].IsU32())
+    {
+      uint32_t val = it.word(3);
+      if(m_U32Consts[val] == opdata.result)
+        m_U32Consts[val] = rdcspv::Id();
+    }
+  }
 }
 
 void Editor::RegisterBuiltinMembers(rdcspv::Id baseId, const rdcarray<uint32_t> chainSoFar,
diff --git a/renderdoc/driver/shaders/spirv/spirv_editor.h b/renderdoc/driver/shaders/spirv/spirv_editor.h
index 6c70cdec5..415d32dbd 100644
--- a/renderdoc/driver/shaders/spirv/spirv_editor.h
+++ b/renderdoc/driver/shaders/spirv/spirv_editor.h
@@ -26,6 +26,7 @@
 
 #include <stdint.h>
 #include <map>
+#include <unordered_map>
 #include "api/replay/rdcarray.h"
 #include "spirv_common.h"
 #include "spirv_processor.h"
@@ -297,6 +298,9 @@ private:
 
   std::map<BuiltIn, BuiltinInputData> builtinInputs;
 
+  // optimise for repeated U32 constants, only register once
+  std::unordered_map<uint32_t, rdcspv::Id> m_U32Consts;
+
   BufferStorageMode m_StorageMode = BufferStorageMode::Unknown;
 
   std::map<Id, Binding> bindings;
@@ -335,6 +339,18 @@ inline Id Editor::AddConstantImmediate(bool b)
   return AddConstant(Operation(b ? Op::ConstantTrue : Op::ConstantFalse, words));
 }
 
+template <>
+inline Id Editor::AddConstantImmediate(uint32_t b)
+{
+  Id typeId = DeclareType(scalar<uint32_t>());
+
+  if(m_U32Consts[b] != rdcspv::Id())
+    return m_U32Consts[b];
+
+  rdcspv::Id constantId = MakeId();
+  return AddConstant(Operation(Op::Constant, {typeId.value(), constantId.value(), b}));
+}
+
 template <>
 inline Id Editor::AddSpecConstantImmediate(bool b, uint32_t specId)
 {
diff --git a/renderdoc/driver/shaders/spirv/spirv_processor.h b/renderdoc/driver/shaders/spirv/spirv_processor.h
index afdeaa3c9..830c4a5fa 100644
--- a/renderdoc/driver/shaders/spirv/spirv_processor.h
+++ b/renderdoc/driver/shaders/spirv/spirv_processor.h
@@ -372,6 +372,11 @@ struct DataType
   const Vector &vector() const { return basicType.vector; }
   const Matrix &matrix() const { return basicType; }
   Id InnerType() const { return pointerType.baseId; }
+  bool IsU32() const
+  {
+    return type == Type::ScalarType && basicType.vector.scalar.width == 32 &&
+           basicType.vector.scalar.type == Op::TypeInt && !basicType.vector.scalar.signedness;
+  }
   bool IsOpaqueType() const
   {
     switch(type)