Remove EvaluateBSDF_Area()

BEFORE
; Disassembly for GCN (Pitcairn)
; -------- Statistics ---------------------
; SGPRs: 100 out of 104 used
; VGPRs: 156 out of 256 used
; LDS: 0 out of 32768 bytes used
; 0 bytes scratch space used
; Instructions: 2652 ALU, 178 Control Flow, 78 TFETCH

AFTER
; Disassembly for GCN (Pitcairn)
; -------- Statistics ---------------------
; SGPRs: 100 out of 104 used
; VGPRs: 156 out of 256 used
; LDS: 0 out of 32768 bytes used
; 0 bytes scratch space used
; Instructions: 2651 ALU, 160 Control Flow, 82 TFETCH

There are 2 extra texture fetches (at the end of one of the area light loops) rather than 4 - the statistics are being pessimistic. These are repeated texture fetches and are a 100% cache hit.

ScriptableRenderPipeline/HDRenderPipeline/Lighting/TilePass/TilePassLoop.hlsl

         i = 0;
         if (areaLightCount > 0)
         {
-            uint areaIndex = FetchIndex(areaLightStart, 0);
-            uint lightType = _LightDatas[areaIndex].lightType;
+            uint      lastIndex = areaLightCount - 1;
+            LightData lightData = _LightDatas[FetchIndex(areaLightStart, 0)];
-            while (i < areaLightCount && lightType == GPULIGHTTYPE_LINE)
+            while (i <= lastIndex && lightData.lightType == GPULIGHTTYPE_LINE)
-                DirectLighting lighting = EvaluateBSDF_Area(context, V, posInput, preLightData, _LightDatas[areaIndex], bsdfData, bakeLightingData, GPULIGHTTYPE_LINE);
+                DirectLighting lighting = EvaluateBSDF_Line(context, V, posInput, preLightData, lightData, bsdfData, bakeLightingData);
-                i++;
-                areaIndex = i < areaLightCount ? FetchIndex(areaLightStart, i) : 0;
-                lightType = i < areaLightCount ? _LightDatas[areaIndex].lightType : 0xFF;
+                lightData = _LightDatas[FetchIndex(areaLightStart, min(++i, lastIndex))];
-            while (i < areaLightCount && lightType == GPULIGHTTYPE_RECTANGLE)
+            while (i <= lastIndex && lightData.lightType == GPULIGHTTYPE_RECTANGLE)
-                DirectLighting lighting = EvaluateBSDF_Area(context, V, posInput, preLightData, _LightDatas[areaIndex], bsdfData, bakeLightingData, GPULIGHTTYPE_RECTANGLE);
+                DirectLighting lighting = EvaluateBSDF_Rect(context, V, posInput, preLightData, lightData, bsdfData, bakeLightingData);
-                i++;
-                areaIndex = i < areaLightCount ? FetchIndex(areaLightStart, i) : 0;
-                lightType = i < areaLightCount ? _LightDatas[areaIndex].lightType : 0xFF;
+                lightData = _LightDatas[FetchIndex(areaLightStart, min(++i, lastIndex))];
             }
         }
 
         {
-            DirectLighting lighting = EvaluateBSDF_Area(context, V, posInput, preLightData, _LightDatas[i], bsdfData, bakeLightingData, _LightDatas[i].lightType);
+            DirectLighting lighting;
+
+            if (_LightDatas[i].lightType == GPULIGHTTYPE_LINE)
+            {
+                lighting = EvaluateBSDF_Line(context, V, posInput, preLightData, _LightDatas[i], bsdfData, bakeLightingData);
+            }
+            else // GPULIGHTTYPE_RECTANGLE
+            {
+                lighting = EvaluateBSDF_Rect(context, V, posInput, preLightData, _LightDatas[i], bsdfData, bakeLightingData);
+            }
+
             AccumulateDirectLighting(lighting, aggregateLighting);
         }
 

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.hlsl

     return lighting;
 }
 
-DirectLighting EvaluateBSDF_Area(   LightLoopContext lightLoopContext,
-                                    float3 V, PositionInputs posInput,
-                                    PreLightData preLightData, LightData lightData, BSDFData bsdfData, BakeLightingData bakeLightingData, int GPULightType)
-{
-    if (GPULightType == GPULIGHTTYPE_LINE)
-    {
-        return EvaluateBSDF_Line(lightLoopContext, V, posInput, preLightData, lightData, bsdfData, bakeLightingData);
-    }
-    else
-    {
-        return EvaluateBSDF_Rect(lightLoopContext, V, posInput, preLightData, lightData, bsdfData, bakeLightingData);
-    }
-}
-
 //-----------------------------------------------------------------------------
 // EvaluateBSDF_SSLighting for screen space lighting
 // ----------------------------------------------------------------------------