shader_ir: Remove RZ and use Register::ZeroIndex instead

src/video_core/shader/decode/memory.cpp

@@ -91,12 +91,14 @@ u32 ShaderIR::DecodeMemory(BasicBlock& bb, u32 pc) {
                 GetConstBufferIndirect(instr.cbuf36.index, instr.cbuf36.offset + 4, index);
 
             const Node composite =
-                Operation(OperationCode::Composite, op_a, op_b, GetRegister(RZ), GetRegister(RZ));
+                Operation(OperationCode::Composite, op_a, op_b, GetRegister(Register::ZeroIndex),
+                          GetRegister(Register::ZeroIndex));
 
             MetaComponents meta{{0, 1, 2, 3}};
             bb.push_back(Operation(OperationCode::AssignComposite, meta, composite,
                                    GetRegister(instr.gpr0), GetRegister(instr.gpr0.Value() + 1),
-                                   GetRegister(RZ), GetRegister(RZ)));
+                                   GetRegister(Register::ZeroIndex),
+                                   GetRegister(Register::ZeroIndex)));
             break;
         }
         default:
@@ -197,7 +199,8 @@ u32 ShaderIR::DecodeMemory(BasicBlock& bb, u32 pc) {
 
             ++dest_elem;
         }
-        std::generate(dest.begin() + dest_elem, dest.end(), [&]() { return GetRegister(RZ); });
+        std::generate(dest.begin() + dest_elem, dest.end(),
+                      [&]() { return GetRegister(Register::ZeroIndex); });
 
         bb.push_back(Operation(OperationCode::AssignComposite, std::move(meta), texture, dest[0],
                                dest[1], dest[2], dest[3]));
@@ -255,7 +258,8 @@ u32 ShaderIR::DecodeMemory(BasicBlock& bb, u32 pc) {
 
             ++dest_elem;
         }
-        std::generate(dest.begin() + dest_elem, dest.end(), [&]() { return GetRegister(RZ); });
+        std::generate(dest.begin() + dest_elem, dest.end(),
+                      [&]() { return GetRegister(Register::ZeroIndex); });
 
         bb.push_back(Operation(OperationCode::AssignComposite, std::move(meta_components), texture,
                                dest[0], dest[1], dest[2], dest[3]));
@@ -369,7 +373,7 @@ u32 ShaderIR::DecodeMemory(BasicBlock& bb, u32 pc) {
         const MetaComponents meta_composite{{0, 1, 2, 3}};
         bb.push_back(Operation(OperationCode::AssignComposite, meta_composite, texture,
                                GetRegister(instr.gpr0), GetRegister(instr.gpr0.Value() + 1),
-                               GetRegister(RZ), GetRegister(RZ)));
+                               GetRegister(Register::ZeroIndex), GetRegister(Register::ZeroIndex)));
         break;
     }
     case OpCode::Id::TLDS: {
@@ -438,7 +442,8 @@ void ShaderIR::WriteTexsInstructionFloat(BasicBlock& bb, Instruction instr, Node
         ++meta.count;
     }
 
-    std::generate(dest.begin() + meta.count, dest.end(), [&]() { return GetRegister(RZ); });
+    std::generate(dest.begin() + meta.count, dest.end(),
+                  [&]() { return GetRegister(Register::ZeroIndex); });
 
     bb.push_back(Operation(OperationCode::AssignComposite, meta, texture, dest[0], dest[1], dest[2],
                            dest[3]));

src/video_core/shader/glsl_decompiler.cpp

@@ -22,6 +22,7 @@ using Tegra::Shader::Header;
 using Tegra::Shader::IpaInterpMode;
 using Tegra::Shader::IpaMode;
 using Tegra::Shader::IpaSampleMode;
+using Tegra::Shader::Register;
 using namespace VideoCommon::Shader;
 
 using Maxwell = Tegra::Engines::Maxwell3D::Regs;
@@ -419,7 +420,7 @@ private:
 
         } else if (const auto gpr = std::get_if<GprNode>(node)) {
             const u32 index = gpr->GetIndex();
-            if (index == RZ) {
+            if (index == Register::ZeroIndex) {
                 return "0";
             }
             return GetRegister(index);
@@ -728,8 +729,8 @@ private:
 
         std::string target;
         if (const auto gpr = std::get_if<GprNode>(dest)) {
-            if (gpr->GetIndex() == RZ) {
-                // Writing to RZ is a no op
+            if (gpr->GetIndex() == Register::ZeroIndex) {
+                // Writing to Register::ZeroIndex is a no op
                 return {};
             }
             target = GetRegister(gpr->GetIndex());
@@ -776,7 +777,7 @@ private:
         constexpr u32 composite_size = 4;
         for (u32 i = 0; i < composite_size; ++i) {
             const auto gpr = std::get<GprNode>(*operation[i + 1]).GetIndex();
-            if (gpr == RZ) {
+            if (gpr == Register::ZeroIndex) {
                 continue;
             }
             code.AddLine(GetRegister(gpr) + " = " + composite +

src/video_core/shader/shader_ir.h

@@ -41,8 +41,6 @@ using BasicBlock = std::vector<Node>;
 
 constexpr u32 MAX_PROGRAM_LENGTH = 0x1000;
 
-constexpr u32 RZ = 0xff;
-
 enum class OperationCode {
     Assign,              /// (float& dest, float src) -> void
     AssignComposite,     /// (MetaComponents, float4 src, float&[4] dst) -> void