gl_shader_decompiler: Reimplement shuffles with platform agnostic intrinsics

src/video_core/renderer_opengl/gl_shader_cache.cpp

@@ -275,6 +275,7 @@ CachedProgram BuildShader(const Device& device, u64 unique_identifier, ProgramTy
     std::string source = fmt::format(R"(// {}
 #version 430 core
 #extension GL_ARB_separate_shader_objects : enable
+#extension GL_ARB_shader_ballot : enable
 #extension GL_ARB_shader_viewport_layer_array : enable
 #extension GL_EXT_shader_image_load_formatted : enable
 #extension GL_NV_gpu_shader5 : enable

src/video_core/renderer_opengl/gl_shader_decompiler.cpp

@@ -1942,34 +1942,14 @@ private:
         return Vote(operation, "allThreadsEqualNV");
     }
 
-    template <const std::string_view& func>
+    Expression ThreadId(Operation operation) {
-    Expression Shuffle(Operation operation) {
+        return {"gl_SubGroupInvocationARB", Type::Uint};
+    }
+
+    Expression ShuffleIndexed(Operation operation) {
         const std::string value = VisitOperand(operation, 0).AsFloat();
-        if (!device.HasWarpIntrinsics()) {
-            LOG_ERROR(Render_OpenGL, "Nvidia shuffle intrinsics are required by this shader");
-            // On a "single-thread" device we are either on the same thread or out of bounds. Both
-            // cases return the passed value.
-            return {value, Type::Float};
-        }
-
         const std::string index = VisitOperand(operation, 1).AsUint();
-        const std::string width = VisitOperand(operation, 2).AsUint();
+        return {fmt::format("readInvocationARB({}, {})", value, index), Type::Float};
-        return {fmt::format("{}({}, {}, {})", func, value, index, width), Type::Float};
-    }
-
-    template <const std::string_view& func>
-    Expression InRangeShuffle(Operation operation) {
-        const std::string index = VisitOperand(operation, 0).AsUint();
-        const std::string width = VisitOperand(operation, 1).AsUint();
-        if (!device.HasWarpIntrinsics()) {
-            // On a "single-thread" device we are only in bounds when the requested index is 0.
-            return {fmt::format("({} == 0U)", index), Type::Bool};
-        }
-
-        const std::string in_range = code.GenerateTemporary();
-        code.AddLine("bool {};", in_range);
-        code.AddLine("{}(0U, {}, {}, {});", func, index, width, in_range);
-        return {in_range, Type::Bool};
     }
 
     struct Func final {
@@ -1981,11 +1961,6 @@ private:
         static constexpr std::string_view Or = "Or";
         static constexpr std::string_view Xor = "Xor";
         static constexpr std::string_view Exchange = "Exchange";
-
-        static constexpr std::string_view ShuffleIndexed = "shuffleNV";
-        static constexpr std::string_view ShuffleUp = "shuffleUpNV";
-        static constexpr std::string_view ShuffleDown = "shuffleDownNV";
-        static constexpr std::string_view ShuffleButterfly = "shuffleXorNV";
     };
 
     static constexpr std::array operation_decompilers = {
@@ -2151,15 +2126,8 @@ private:
         &GLSLDecompiler::VoteAny,
         &GLSLDecompiler::VoteEqual,
 
-        &GLSLDecompiler::Shuffle<Func::ShuffleIndexed>,
+        &GLSLDecompiler::ThreadId,
-        &GLSLDecompiler::Shuffle<Func::ShuffleUp>,
+        &GLSLDecompiler::ShuffleIndexed,
-        &GLSLDecompiler::Shuffle<Func::ShuffleDown>,
-        &GLSLDecompiler::Shuffle<Func::ShuffleButterfly>,
-
-        &GLSLDecompiler::InRangeShuffle<Func::ShuffleIndexed>,
-        &GLSLDecompiler::InRangeShuffle<Func::ShuffleUp>,
-        &GLSLDecompiler::InRangeShuffle<Func::ShuffleDown>,
-        &GLSLDecompiler::InRangeShuffle<Func::ShuffleButterfly>,
     };
     static_assert(operation_decompilers.size() == static_cast<std::size_t>(OperationCode::Amount));
 

src/video_core/renderer_vulkan/vk_shader_decompiler.cpp

@@ -1195,46 +1195,16 @@ private:
         return {};
     }
 
+    Id ThreadId(Operation) {
+        UNIMPLEMENTED();
+        return {};
+    }
+
     Id ShuffleIndexed(Operation) {
         UNIMPLEMENTED();
         return {};
     }
 
-    Id ShuffleUp(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
-    Id ShuffleDown(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
-    Id ShuffleButterfly(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
-    Id InRangeShuffleIndexed(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
-    Id InRangeShuffleUp(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
-    Id InRangeShuffleDown(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
-    Id InRangeShuffleButterfly(Operation) {
-        UNIMPLEMENTED();
-        return {};
-    }
-
     Id DeclareBuiltIn(spv::BuiltIn builtin, spv::StorageClass storage, Id type,
                       const std::string& name) {
         const Id id = OpVariable(type, storage);
@@ -1528,15 +1498,8 @@ private:
         &SPIRVDecompiler::VoteAny,
         &SPIRVDecompiler::VoteEqual,
 
+        &SPIRVDecompiler::ThreadId,
         &SPIRVDecompiler::ShuffleIndexed,
-        &SPIRVDecompiler::ShuffleUp,
-        &SPIRVDecompiler::ShuffleDown,
-        &SPIRVDecompiler::ShuffleButterfly,
-
-        &SPIRVDecompiler::InRangeShuffleIndexed,
-        &SPIRVDecompiler::InRangeShuffleUp,
-        &SPIRVDecompiler::InRangeShuffleDown,
-        &SPIRVDecompiler::InRangeShuffleButterfly,
     };
     static_assert(operation_decompilers.size() == static_cast<std::size_t>(OperationCode::Amount));
 

src/video_core/shader/decode/warp.cpp

@@ -17,6 +17,7 @@ using Tegra::Shader::ShuffleOperation;
 using Tegra::Shader::VoteOperation;
 
 namespace {
+
 OperationCode GetOperationCode(VoteOperation vote_op) {
     switch (vote_op) {
     case VoteOperation::All:
@@ -30,6 +31,7 @@ OperationCode GetOperationCode(VoteOperation vote_op) {
         return OperationCode::VoteAll;
     }
 }
+
 } // Anonymous namespace
 
 u32 ShaderIR::DecodeWarp(NodeBlock& bb, u32 pc) {
@@ -46,50 +48,50 @@ u32 ShaderIR::DecodeWarp(NodeBlock& bb, u32 pc) {
         break;
     }
     case OpCode::Id::SHFL: {
-        Node width = [this, instr] {
         Node mask = instr.shfl.is_mask_imm ? Immediate(static_cast<u32>(instr.shfl.mask_imm))
                                            : GetRegister(instr.gpr39);
-
-            // Convert the obscure SHFL mask back into GL_NV_shader_thread_shuffle's width. This has
-            // been done reversing Nvidia's math. It won't work on all cases due to SHFL having
-            // different parameters that don't properly map to GLSL's interface, but it should work
-            // for cases emitted by Nvidia's compiler.
-            if (instr.shfl.operation == ShuffleOperation::Up) {
-                return Operation(
-                    OperationCode::ILogicalShiftRight,
-                    Operation(OperationCode::IAdd, std::move(mask), Immediate(-0x2000)),
-                    Immediate(8));
-            } else {
-                return Operation(OperationCode::ILogicalShiftRight,
-                                 Operation(OperationCode::IAdd, Immediate(0x201F),
-                                           Operation(OperationCode::INegate, std::move(mask))),
-                                 Immediate(8));
-            }
-        }();
-
-        const auto [operation, in_range] = [instr]() -> std::pair<OperationCode, OperationCode> {
-            switch (instr.shfl.operation) {
-            case ShuffleOperation::Idx:
-                return {OperationCode::ShuffleIndexed, OperationCode::InRangeShuffleIndexed};
-            case ShuffleOperation::Up:
-                return {OperationCode::ShuffleUp, OperationCode::InRangeShuffleUp};
-            case ShuffleOperation::Down:
-                return {OperationCode::ShuffleDown, OperationCode::InRangeShuffleDown};
-            case ShuffleOperation::Bfly:
-                return {OperationCode::ShuffleButterfly, OperationCode::InRangeShuffleButterfly};
-            }
-            UNREACHABLE_MSG("Invalid SHFL operation: {}",
-                            static_cast<u64>(instr.shfl.operation.Value()));
-            return {};
-        }();
-
-        // Setting the predicate before the register is intentional to avoid overwriting.
         Node index = instr.shfl.is_index_imm ? Immediate(static_cast<u32>(instr.shfl.index_imm))
                                              : GetRegister(instr.gpr20);
-        SetPredicate(bb, instr.shfl.pred48, Operation(in_range, index, width));
+
+        Node thread_id = Operation(OperationCode::ThreadId);
+        Node clamp = Operation(OperationCode::IBitwiseAnd, mask, Immediate(0x1FU));
+        Node seg_mask = BitfieldExtract(mask, 8, 16);
+
+        Node neg_seg_mask = Operation(OperationCode::IBitwiseNot, seg_mask);
+        Node min_thread_id = Operation(OperationCode::IBitwiseAnd, thread_id, seg_mask);
+        Node max_thread_id = Operation(OperationCode::IBitwiseOr, min_thread_id,
+                                       Operation(OperationCode::IBitwiseAnd, clamp, neg_seg_mask));
+
+        Node src_thread_id = [instr, index, neg_seg_mask, min_thread_id, thread_id] {
+            switch (instr.shfl.operation) {
+            case ShuffleOperation::Idx:
+                return Operation(OperationCode::IBitwiseOr,
+                                 Operation(OperationCode::IBitwiseAnd, index, neg_seg_mask),
+                                 min_thread_id);
+            case ShuffleOperation::Down:
+                return Operation(OperationCode::IAdd, thread_id, index);
+            case ShuffleOperation::Up:
+                return Operation(OperationCode::IAdd, thread_id,
+                                 Operation(OperationCode::INegate, index));
+            case ShuffleOperation::Bfly:
+                return Operation(OperationCode::IBitwiseXor, thread_id, index);
+            }
+            UNREACHABLE();
+            return Immediate(0U);
+        }();
+
+        Node in_bounds = [instr, src_thread_id, min_thread_id, max_thread_id] {
+            if (instr.shfl.operation == ShuffleOperation::Up) {
+                return Operation(OperationCode::LogicalIGreaterEqual, src_thread_id, min_thread_id);
+            } else {
+                return Operation(OperationCode::LogicalILessEqual, src_thread_id, max_thread_id);
+            }
+        }();
+
+        SetPredicate(bb, instr.shfl.pred48, in_bounds);
         SetRegister(
             bb, instr.gpr0,
-            Operation(operation, GetRegister(instr.gpr8), std::move(index), std::move(width)));
+            Operation(OperationCode::ShuffleIndexed, GetRegister(instr.gpr8), src_thread_id));
         break;
     }
     default:

src/video_core/shader/node.h

@@ -181,15 +181,8 @@ enum class OperationCode {
     VoteAny,      /// (bool) -> bool
     VoteEqual,    /// (bool) -> bool
 
-    ShuffleIndexed,   /// (uint value, uint index, uint width) -> uint
+    ThreadId,       /// () -> uint
-    ShuffleUp,        /// (uint value, uint index, uint width) -> uint
+    ShuffleIndexed, /// (uint value, uint index) -> uint
-    ShuffleDown,      /// (uint value, uint index, uint width) -> uint
-    ShuffleButterfly, /// (uint value, uint index, uint width) -> uint
-
-    InRangeShuffleIndexed,   /// (uint index, uint width) -> bool
-    InRangeShuffleUp,        /// (uint index, uint width) -> bool
-    InRangeShuffleDown,      /// (uint index, uint width) -> bool
-    InRangeShuffleButterfly, /// (uint index, uint width) -> bool
 
     Amount,
 };