1 files changed, 34 insertions, 2 deletions
diff --git a/source/slang/slang-ir-insert-debug-value-store.cpp b/source/slang/slang-ir-insert-debug-value-store.cpp
index 8aad3e417..6243e6c09 100644
--- a/source/slang/slang-ir-insert-debug-value-store.cpp
+++ b/source/slang/slang-ir-insert-debug-value-store.cpp
@@ -80,6 +80,38 @@ namespace Slang
         }
 
         // Collect all stores and insert debug value insts to update debug vars.
+
+        // Helper func to insert debugValue updates.
+        auto setDebugValue = [&](IRInst* debugVar, IRInst* rootVar, IRInst* newValue, ArrayView<IRInst*> accessChain)
+            {
+                // SPIRV does not allow dynamic indices in DebugValue,
+                // so we need to stop the access chain at the first dynamic index.
+                Index i = 0;
+                for (; i < accessChain.getCount(); i++)
+                {
+                    if (auto key = as<IRStructKey>(accessChain[i]))
+                    {
+                        continue;
+                    }
+                    if (as<IRIntLit>(accessChain[i]))
+                    {
+                        continue;
+                    }
+                    break;
+                }
+                // If everything is static on the access chain, we can simply emit a DebugValue.
+                if (i == accessChain.getCount())
+                {
+                    builder.emitDebugValue(debugVar, newValue, accessChain);
+                    return;
+                }
+                
+                // Otherwise we need to load the entire composite value starting at the dynamic index access chain
+                // and set it.
+                auto compositePtr = builder.emitElementAddress(rootVar, accessChain.head(i));
+                auto compositeVal = builder.emitLoad(compositePtr);
+                builder.emitDebugValue(debugVar, compositeVal, accessChain.head(i));
+            };
         for (auto block : func->getBlocks())
         {
             IRInst* nextInst = nullptr;
@@ -95,7 +127,7 @@ namespace Slang
                     if (mapVarToDebugVar.tryGetValue(varInst, debugVar))
                     {
                         builder.setInsertAfter(storeInst);
-                        builder.emitDebugValue(debugVar, storeInst->getVal(), accessChain.getArrayView());
+                        setDebugValue(debugVar, varInst, storeInst->getVal(), accessChain.getArrayView());
                     }
                 }
                 else if (auto callInst = as<IRCall>(inst))
@@ -115,7 +147,7 @@ namespace Slang
                         {
                             builder.setInsertAfter(callInst);
                             auto loadVal = builder.emitLoad(arg);
-                            builder.emitDebugValue(debugVar, loadVal, accessChain.getArrayView());
+                            setDebugValue(debugVar, varInst, loadVal, accessChain.getArrayView());
                         }
                     }
                 }