Allow SV_PrimitiveID in ray tracing hit stages

source/slang/core.meta.slang

@@ -5050,6 +5050,9 @@ semantic sv_primitiveid
     [require(geometry)]
     [require(hull)]
     [require(domain)]
+    [require(intersection)]
+    [require(anyhit)]
+    [require(closesthit)]
     get : uint;
 
     [require(geometry)]

source/slang/slang-emit.cpp

@@ -1638,11 +1638,12 @@ Result linkAndOptimizeIR(
             SLANG_PASS(legalizeEmptyRayPayloadsForHLSL);
         }
 
-        // For DXIL only: unwrap ForceVarIntoRayPayloadStructTemporarily instructions
-        // (must run before legalizeExistentialTypeLayout removes empty struct parameters)
+        // For DXIL/HLSL: rewrite parameters that need backend intrinsics or
+        // temporary structs before existential layout removes empty struct
+        // parameters.
         if (isD3DTarget(targetRequest))
         {
-            SLANG_PASS(legalizeNonStructParameterToStructForHLSL);
+            SLANG_PASS(legalizeParametersForHLSL);
         }
 
         if (requiredLoweringPassSet.existentialTypeLayout)

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

@@ -5,6 +5,7 @@
 #include "slang-ir-clone.h"
 #include "slang-ir-inst-pass-base.h"
 #include "slang-ir-insts.h"
+#include "slang-ir-legalize-varying-params.h"
 #include "slang-ir-single-return.h"
 #include "slang-ir-specialize-function-call.h"
 #include "slang-ir-util.h"
@@ -3093,6 +3094,7 @@ void consolidateRayTracingParameters(GLSLLegalizationContext* context, IRFunc* f
         auto paramLayout = findVarLayout(param);
         if (!isVaryingParameter(paramLayout))
             continue;
+
         builder->setInsertBefore(firstBlock->getFirstOrdinaryInst());
         if (as<IROutParamType>(param->getDataType()) ||
             as<IRBorrowInOutParamType>(param->getDataType()))
@@ -4820,6 +4822,8 @@ void legalizeEntryPointForGLSL(
     SLANG_ASSERT(entryPointDecor);
 
     auto stage = entryPointDecor->getProfile().getStage();
+    const bool shouldEmitSPIRVDirectly =
+        codeGenContext->getTargetProgram()->shouldEmitSPIRVDirectly();
 
     auto layoutDecoration = func->findDecoration<IRLayoutDecoration>();
     SLANG_ASSERT(layoutDecoration);
@@ -4909,6 +4913,26 @@ void legalizeEntryPointForGLSL(
         invokePathConstantFuncInHullShader(&context, codeGenContext, scalarizedGlobalOutput);
     }
 
+    if (isRayTracingHitStage(stage) && !shouldEmitSPIRVDirectly)
+    {
+        IRFunc* primitiveIndexFunc = nullptr;
+        if (auto firstBlock = func->getFirstBlock())
+        {
+            for (auto pp = firstBlock->getFirstParam(); pp;)
+            {
+                auto next = pp->getNextParam();
+                builder.setInsertBefore(firstBlock->getFirstOrdinaryInst());
+                tryLegalizeRayTracingPrimitiveIDParam(
+                    module,
+                    builder,
+                    pp,
+                    primitiveIndexFunc,
+                    /* removeParam */ true);
+                pp = next;
+            }
+        }
+    }
+
     // Special handling for ray tracing shaders
     switch (stage)
     {

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

@@ -3,12 +3,11 @@
 
 #include "slang-ir-inst-pass-base.h"
 #include "slang-ir-insts.h"
+#include "slang-ir-legalize-varying-params.h"
 #include "slang-ir-specialize-function-call.h"
 #include "slang-ir-util.h"
 #include "slang-ir.h"
 
-#include <functional>
-
 namespace Slang
 {
 
@@ -160,16 +159,27 @@ void searchChildrenForForceVarIntoStructTemporarily(IRModule* module, IRInst* in
     }
 }
 
-void legalizeNonStructParameterToStructForHLSL(IRModule* module)
+void legalizeParametersForHLSL(IRModule* module)
 {
+    List<IRFunc*> funcs;
+
     for (auto globalInst : module->getGlobalInsts())
     {
         // Only process functions - at this stage generics are already resolved,
         // and the search only handles Block and Call children.
-        if (globalInst->getOp() != kIROp_Func)
+        auto func = as<IRFunc>(globalInst);
+        if (!func)
             continue;
-        searchChildrenForForceVarIntoStructTemporarily(module, globalInst);
+
+        funcs.add(func);
     }
+
+    for (auto func : funcs)
+    {
+        searchChildrenForForceVarIntoStructTemporarily(module, func);
+    }
+
+    legalizeRayTracingPrimitiveIDParamsForHLSL(module);
 }
 
 void legalizeEmptyRayPayloadsForHLSL(IRModule* module)

source/slang/slang-ir-hlsl-legalize.h

@@ -12,7 +12,7 @@ class Session;
 struct IRFunc;
 struct IRModule;
 
-void legalizeNonStructParameterToStructForHLSL(IRModule* module);
+void legalizeParametersForHLSL(IRModule* module);
 
 void legalizeEmptyRayPayloadsForHLSL(IRModule* module);