diff --git a/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp b/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp
index 1fcbe3225..827cb51e9 100644
--- a/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp
+++ b/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp
@@ -2558,7 +2558,7 @@ void LLVMOrderAccumulator::processGlobals(Program *prog, bool doLiveChecking)
   }
 }
 
-void LLVMOrderAccumulator::processFunction(const Function *f)
+void LLVMOrderAccumulator::processFunction(const Function *f, uint32_t *nextSSAId)
 {
   const Function &func = *f;
 
@@ -2611,8 +2611,18 @@ void LLVMOrderAccumulator::processFunction(const Function *f)
   uint32_t curBlock = 0;
 
   for(Instruction *arg : func.args)
+  {
+#if DISABLED(DXC_COMPATIBLE_DISASM)
+    if(arg->slot == ~0U)
+    {
+      arg->slot = *nextSSAId;
+      (*nextSSAId)++;
+    }
+#else
     if(arg->getName().isEmpty())
       arg->slot = slot++;
+#endif
+  }
 
   if(!func.blocks.empty() && func.blocks[0]->name.empty())
     func.blocks[0]->slot = slot++;
@@ -2636,8 +2646,16 @@ void LLVMOrderAccumulator::processFunction(const Function *f)
     {
       accumulate(inst);
 
+#if DISABLED(DXC_COMPATIBLE_DISASM)
+      if(inst->slot == ~0U)
+      {
+        inst->slot = *nextSSAId;
+        (*nextSSAId)++;
+      }
+#else
       if(inst->getName().isEmpty())
         inst->slot = slot++;
+#endif
     }
 
     if(inst->op == Operation::Branch || inst->op == Operation::Unreachable ||
diff --git a/renderdoc/driver/shaders/dxil/dxil_bytecode.h b/renderdoc/driver/shaders/dxil/dxil_bytecode.h
index 9cf1ea80e..6c3e72a8c 100644
--- a/renderdoc/driver/shaders/dxil/dxil_bytecode.h
+++ b/renderdoc/driver/shaders/dxil/dxil_bytecode.h
@@ -1263,7 +1263,10 @@ struct Instruction : public ForwardReferencableValue<Instruction>
   uint32_t debugLoc = ~0U;
   Operation op = Operation::NoOp;
   uint8_t align = 0;
-  // number assigned to instructions that don't have names and return a value, for disassembly
+  // For DXC Compatibility mode: slot contains a number assigned to instructions that don't have
+  // names and return a value, used for disassembly
+
+  // Otherwise a unique global ID used by the debugger and disassemvbly
   uint32_t slot = ~0U;
   InstructionFlags &opFlags() { return (InstructionFlags &)flags; }
   InstructionFlags opFlags() const { return (InstructionFlags)flags; }
@@ -1384,7 +1387,7 @@ public:
   size_t firstFuncConst;
   size_t numFuncConsts;
 
-  void processFunction(const Function *f);
+  void processFunction(const Function *f, uint32_t *nextSSAId = NULL);
   void exitFunction();
 
 private:
@@ -1645,6 +1648,7 @@ protected:
   rdcarray<Metadata *> m_MetaSlots;
   rdcarray<const AttributeGroup *> m_FuncAttrGroups;
   uint32_t m_NextMetaSlot = 0;
+  uint32_t m_NextSSAId = 0;
 
   bool m_Uselists = false;
   bool m_DXCStyle = false;
diff --git a/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp b/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp
index 6e666f77b..54da1a695 100644
--- a/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp
+++ b/renderdoc/driver/shaders/dxil/dxil_disassemble.cpp
@@ -1043,6 +1043,7 @@ void Program::Parse(const DXBC::Reflection *reflection)
 
 void Program::SettleIDs()
 {
+  RDCASSERTEQUAL(m_NextSSAId, 0);
   RDCASSERTEQUAL(m_NextMetaSlot, 0);
   RDCASSERT(m_MetaSlots.isEmpty());
 
@@ -1063,7 +1064,7 @@ void Program::SettleIDs()
   uint32_t &nextMetaSlot = m_NextMetaSlot;
   for(size_t i = 0; i < m_Functions.size(); i++)
   {
-    m_Accum.processFunction(m_Functions[i]);
+    m_Accum.processFunction(m_Functions[i], &m_NextSSAId);
 
     Function &func = *m_Functions[i];