Fix several shader and C# warning

ScriptableRenderPipeline/Core/CoreRP/ShaderLibrary/BSDF.hlsl

 }
 
 // Evaluate the reflectance for a thin-film layer on top of a dielectric medum.
-real3 EvalIridescence(real eta_1, real cosTheta1, real iridescenceThickness, real baseLayerFresnel0)
+real3 EvalIridescence(real eta_1, real cosTheta1, real iridescenceThickness, real3 baseLayerFresnel0)
 {
     // iridescenceThickness unit is micrometer for this equation here. Mean 0.5 is 500nm.
     real Dinc = 3.0 * iridescenceThickness;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Debug/DebugDisplay.hlsl

     }
 
     // 4. Display leading 0
+#pragma warning(disable : 3557) // loop only executes for 0 iteration(s)
+#pragma warning(enable : 3557)
 
     // 5. Display sign
     if (intValue < 0 || forceNegativeSign)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/Lit/StandardsToHDLitMaterialUpgrader.cs

                 RenameTexture("_SpecGlossMap", "_SpecularColorMap");
             }
         }
-        
+
         public override void Convert(Material srcMaterial, Material dstMaterial)
         {
             dstMaterial.hideFlags = HideFlags.DontUnloadUnusedAsset;
                 metallicMap = Texture2D.blackTexture;
 
             // Occlusion
-            bool hasOcclusion = srcMaterial.GetTexture("_OcclusionMap") != null;
-            Texture occlusionMap;
-            if (hasOcclusion) occlusionMap = TextureCombiner.GetTextureSafe(srcMaterial, "_OcclusionMap", Color.white);
+            //bool hasOcclusion = srcMaterial.GetTexture("_OcclusionMap") != null;
+            //Texture occlusionMap;
+            //if (hasOcclusion) occlusionMap = TextureCombiner.GetTextureSafe(srcMaterial, "_OcclusionMap", Color.white);
-            bool hasDetailMask = srcMaterial.GetTexture("_DetailMask") != null;
-            Texture detailMaskMap;
-            if (hasDetailMask) detailMaskMap = TextureCombiner.GetTextureSafe(srcMaterial, "_DetailMask", Color.white);
+            //bool hasDetailMask = srcMaterial.GetTexture("_DetailMask") != null;
+            //Texture detailMaskMap;
+            //if (hasDetailMask) detailMaskMap = TextureCombiner.GetTextureSafe(srcMaterial, "_DetailMask", Color.white);
 
             // Smoothness
             bool hasSmoothness = false;
 
                 if (hasSmoothness)
                     smoothnessMap = (Texture2D)TextureCombiner.GetTextureSafe(srcMaterial, "_SpecGlossMap", Color.grey);
-            }   
+            }
             else
             {
                 string smoothnessTextureChannel = "_MainTex";
                     dstMaterial.SetFloat("_AlphaCutoffEnable", 0);
                     dstMaterial.SetFloat("_EnableBlendModePreserveSpecularLighting", 0);
                     break;
-                case 3: // Transparent -> Alpha 
+                case 3: // Transparent -> Alpha
                     dstMaterial.SetFloat("_SurfaceType", 1);
                     dstMaterial.SetFloat("_BlendMode", 0);
                     dstMaterial.SetFloat("_AlphaCutoffEnable", 0);
             // Emission: Convert the HDR emissive color to ldr color + intensity
             Color hdrEmission = srcMaterial.GetColor("_EmissionColor");
             float intensity = Mathf.Max(hdrEmission.r, Mathf.Max(hdrEmission.g, hdrEmission.b));
-            
+
             if (intensity > 1f)
             {
                 hdrEmission.r /= intensity;
                 intensity = 1f;
 
             intensity = Mathf.Pow(intensity, 2.2f); // Gamma to Linear conversion
-            
+
-            
+
-}
+}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/Unlit/UnlitsToHDUnlitUpgrader.cs

 	public class UnlitsToHDUnlitUpgrader : MaterialUpgrader
 	{
 		string Unlit_Color = "Unlit/Color";
-		string Unlit_Texture = "Unlit/Texture";
+		//string Unlit_Texture = "Unlit/Texture";
 		string Unlit_Transparent = "Unlit/Transparent";
 		string Unlit_Cutout = "Unlit/Transparent Cutout";
 
             //dstMaterial.hideFlags = HideFlags.DontUnloadUnusedAsset;
 
             base.Convert(srcMaterial, dstMaterial);
-            
+
             HDEditorUtils.ResetMaterialKeywords(dstMaterial);
 		}
 	}

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/DecalUtilities.hlsl

 {
 	if(_EnableDBuffer)
 	{
-		DecalSurfaceData decalSurfaceData;		
+		DecalSurfaceData decalSurfaceData;
 		int mask = 0;
 		// the code in the macros, gets moved inside the conditionals by the compiler
 		FETCH_DBUFFER(DBuffer, _DBufferTexture, posInput.positionSS);
         decalStart = 0;
     #endif
 		float3 positionWS = GetAbsolutePositionWS(posInput.positionWS);
-		uint i = 0; 
+		uint i = 0;
-            DecalData decalData = FetchDecal(decalStart, i);    
+            DecalData decalData = FetchDecal(decalStart, i);
 			float3 positionDS = mul(decalData.worldToDecal, float4(positionWS, 1.0)).xyz;
 			positionDS = positionDS * float3(1.0, -1.0, 1.0) + float3(0.5, 0.0f, 0.5);
 			float decalBlend = decalData.normalToWorld[0][3];
 			}
 		}
 #else
-		mask = UnpackByte(LOAD_TEXTURE2D(_DecalHTileTexture, posInput.positionSS / 8)); 
+		mask = UnpackByte(LOAD_TEXTURE2D(_DecalHTileTexture, posInput.positionSS / 8).r);
-		DECODE_FROM_DBUFFER(DBuffer, decalSurfaceData);		
+		DECODE_FROM_DBUFFER(DBuffer, decalSurfaceData);
-		
+
 		if(mask & DBUFFERHTILEBIT_NORMAL)
 		{
 			surfaceData.normalWS.xyz = normalize(surfaceData.normalWS.xyz * decalSurfaceData.normalWS.w + decalSurfaceData.normalWS.xyz);

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Sky/ProceduralSky/Resources/ProceduralSky.shader

 
     static const float kCameraHeight = 0.0001;
 
-    #define kRAYLEIGH (lerp(0.0, 0.0025, pow(_AtmosphereThickness,2.5)))      // Rayleigh constant
+    #define kRAYLEIGH (lerp(0.0, 0.0025, PositivePow(_AtmosphereThickness,2.5)))      // Rayleigh constant
     #define kMIE 0.0010             // Mie constant
     #define kSUN_BRIGHTNESS 20.0    // Sun brightness
 
             kDefaultScatteringWavelength-kVariableRangeForScatteringWavelength,
             kDefaultScatteringWavelength+kVariableRangeForScatteringWavelength,
             float3(1,1,1) - _SkyTint); // using Tint in sRGB gamma allows for more visually linear interpolation and to keep (.5) at (128, gray in sRGB) point
-        float3 kInvWavelength = 1.0 / pow(kScatteringWavelength, 4);
+        float3 kInvWavelength = 1.0 / float3(PositivePow(kScatteringWavelength.x, 4), PositivePow(kScatteringWavelength.y, 4), PositivePow(kScatteringWavelength.z, 4));
 
         float kKrESun = kRAYLEIGH * kSUN_BRIGHTNESS;
         float kKr4PI = kRAYLEIGH * 4.0 * 3.14159265;
             cIn = frontColor * (kInvWavelength * kKrESun + kKmESun);
             cOut = clamp(attenuate, 0.0, 1.0);
 
-            groundColor = _SkyParam.y * (cIn + _GroundColor * _GroundColor * cOut);
+            groundColor = _SkyParam.y * (cIn + _GroundColor.rgb * _GroundColor.rgb * cOut);
         }
 
         float3 sunColor = float3(0.0, 0.0, 0.0);