Fix.

Author: csyonghe

source/slang/slang-ir-spirv-legalize.cpp

@@ -627,12 +627,14 @@ struct SPIRVLegalizationContext : public SourceEmitterBase
 
     AddressSpace getGlobalParamAddressSpace(IRInst* varInst)
     {
-        auto builtinDecor = varInst->findDecoration<IRTargetBuiltinVarDecoration>();
-        switch (builtinDecor->getBuiltinVarName())
+        if (auto builtinDecor = varInst->findDecoration<IRTargetBuiltinVarDecoration>())
         {
-        case IRTargetBuiltinVarName::SpvInstanceIndex:
-        case IRTargetBuiltinVarName::SpvBaseInstance:
-            return AddressSpace::BuiltinInput;
+            switch (builtinDecor->getBuiltinVarName())
+            {
+            case IRTargetBuiltinVarName::SpvInstanceIndex:
+            case IRTargetBuiltinVarName::SpvBaseInstance:
+                return AddressSpace::BuiltinInput;
+            }
         }
 
         auto varLayout = getVarLayout(varInst);