From 8909f52166bf9c27d52b5a722efbd46d1a11e876 Mon Sep 17 00:00:00 2001 From: Fernando Sahmkow Date: Mon, 23 Sep 2019 22:55:25 -0400 Subject: [PATCH] Shader_IR: Implement Fast BRX and allow multi-branches in the CFG. --- .../renderer_opengl/gl_shader_decompiler.cpp | 5 + .../renderer_vulkan/vk_shader_decompiler.cpp | 7 + src/video_core/shader/ast.cpp | 4 + src/video_core/shader/control_flow.cpp | 262 +++++++++++------- src/video_core/shader/control_flow.h | 63 +++-- src/video_core/shader/decode.cpp | 34 ++- src/video_core/shader/expr.h | 17 +- 7 files changed, 260 insertions(+), 132 deletions(-) diff --git a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp index baec66ff0..71d7389cb 100644 --- a/src/video_core/renderer_opengl/gl_shader_decompiler.cpp +++ b/src/video_core/renderer_opengl/gl_shader_decompiler.cpp @@ -2338,6 +2338,11 @@ public: inner += expr.value ? "true" : "false"; } + void operator()(VideoCommon::Shader::ExprGprEqual& expr) { + inner += + "( ftou(" + decomp.GetRegister(expr.gpr) + ") == " + std::to_string(expr.value) + ')'; + } + const std::string& GetResult() const { return inner; } diff --git a/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp b/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp index 0d943a826..42cf068b6 100644 --- a/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp +++ b/src/video_core/renderer_vulkan/vk_shader_decompiler.cpp @@ -1704,6 +1704,13 @@ public: return expr.value ? decomp.v_true : decomp.v_false; } + Id operator()(const ExprGprEqual& expr) { + const Id target = decomp.Constant(decomp.t_uint, expr.value); + const Id gpr = decomp.BitcastTo( + decomp.Emit(decomp.OpLoad(decomp.t_float, decomp.registers.at(expr.gpr)))); + return decomp.Emit(decomp.OpLogicalEqual(decomp.t_uint, gpr, target)); + } + Id Visit(const Expr& node) { return std::visit(*this, *node); } diff --git a/src/video_core/shader/ast.cpp b/src/video_core/shader/ast.cpp index e43aecc18..2fa3a3f7d 100644 --- a/src/video_core/shader/ast.cpp +++ b/src/video_core/shader/ast.cpp @@ -228,6 +228,10 @@ public: inner += expr.value ? "true" : "false"; } + void operator()(ExprGprEqual const& expr) { + inner += "( gpr_" + std::to_string(expr.gpr) + " == " + std::to_string(expr.value) + ')'; + } + const std::string& GetResult() const { return inner; } diff --git a/src/video_core/shader/control_flow.cpp b/src/video_core/shader/control_flow.cpp index dac2e4272..d1c269ea7 100644 --- a/src/video_core/shader/control_flow.cpp +++ b/src/video_core/shader/control_flow.cpp @@ -35,14 +35,24 @@ struct BlockStack { std::stack pbk_stack{}; }; -struct BlockBranchInfo { - Condition condition{}; - s32 address{exit_branch}; - bool kill{}; - bool is_sync{}; - bool is_brk{}; - bool ignore{}; -}; +template +BlockBranchInfo MakeBranchInfo(Args&&... args) { + static_assert(std::is_convertible_v); + return std::make_shared(T(std::forward(args)...)); +} + +bool BlockBranchInfoAreEqual(BlockBranchInfo first, BlockBranchInfo second) { + return false; //(*first) == (*second); +} + +bool BlockBranchIsIgnored(BlockBranchInfo first) { + bool ignore = false; + if (std::holds_alternative(*first)) { + auto branch = std::get_if(first.get()); + ignore = branch->ignore; + } + return ignore; +} struct BlockInfo { u32 start{}; @@ -234,6 +244,7 @@ std::pair ParseCode(CFGRebuildState& state, u32 address) u32 offset = static_cast(address); const u32 end_address = static_cast(state.program_size / sizeof(Instruction)); ParseInfo parse_info{}; + SingleBranch single_branch{}; const auto insert_label = [](CFGRebuildState& state, u32 address) { const auto pair = state.labels.emplace(address); @@ -246,13 +257,14 @@ std::pair ParseCode(CFGRebuildState& state, u32 address) if (offset >= end_address) { // ASSERT_OR_EXECUTE can't be used, as it ignores the break ASSERT_MSG(false, "Shader passed the current limit!"); - parse_info.branch_info.address = exit_branch; - parse_info.branch_info.ignore = false; + + single_branch.address = exit_branch; + single_branch.ignore = false; break; } if (state.registered.count(offset) != 0) { - parse_info.branch_info.address = offset; - parse_info.branch_info.ignore = true; + single_branch.address = offset; + single_branch.ignore = true; break; } if (IsSchedInstruction(offset, state.start)) { @@ -269,24 +281,26 @@ std::pair ParseCode(CFGRebuildState& state, u32 address) switch (opcode->get().GetId()) { case OpCode::Id::EXIT: { const auto pred_index = static_cast(instr.pred.pred_index); - parse_info.branch_info.condition.predicate = - GetPredicate(pred_index, instr.negate_pred != 0); - if (parse_info.branch_info.condition.predicate == Pred::NeverExecute) { + single_branch.condition.predicate = GetPredicate(pred_index, instr.negate_pred != 0); + if (single_branch.condition.predicate == Pred::NeverExecute) { offset++; continue; } const ConditionCode cc = instr.flow_condition_code; - parse_info.branch_info.condition.cc = cc; + single_branch.condition.cc = cc; if (cc == ConditionCode::F) { offset++; continue; } - parse_info.branch_info.address = exit_branch; - parse_info.branch_info.kill = false; - parse_info.branch_info.is_sync = false; - parse_info.branch_info.is_brk = false; - parse_info.branch_info.ignore = false; + single_branch.address = exit_branch; + single_branch.kill = false; + single_branch.is_sync = false; + single_branch.is_brk = false; + single_branch.ignore = false; parse_info.end_address = offset; + parse_info.branch_info = MakeBranchInfo( + single_branch.condition, single_branch.address, single_branch.kill, + single_branch.is_sync, single_branch.is_brk, single_branch.ignore); return {ParseResult::ControlCaught, parse_info}; } @@ -295,99 +309,107 @@ std::pair ParseCode(CFGRebuildState& state, u32 address) return {ParseResult::AbnormalFlow, parse_info}; } const auto pred_index = static_cast(instr.pred.pred_index); - parse_info.branch_info.condition.predicate = - GetPredicate(pred_index, instr.negate_pred != 0); - if (parse_info.branch_info.condition.predicate == Pred::NeverExecute) { + single_branch.condition.predicate = GetPredicate(pred_index, instr.negate_pred != 0); + if (single_branch.condition.predicate == Pred::NeverExecute) { offset++; continue; } const ConditionCode cc = instr.flow_condition_code; - parse_info.branch_info.condition.cc = cc; + single_branch.condition.cc = cc; if (cc == ConditionCode::F) { offset++; continue; } const u32 branch_offset = offset + instr.bra.GetBranchTarget(); if (branch_offset == 0) { - parse_info.branch_info.address = exit_branch; + single_branch.address = exit_branch; } else { - parse_info.branch_info.address = branch_offset; + single_branch.address = branch_offset; } insert_label(state, branch_offset); - parse_info.branch_info.kill = false; - parse_info.branch_info.is_sync = false; - parse_info.branch_info.is_brk = false; - parse_info.branch_info.ignore = false; + single_branch.kill = false; + single_branch.is_sync = false; + single_branch.is_brk = false; + single_branch.ignore = false; parse_info.end_address = offset; + parse_info.branch_info = MakeBranchInfo( + single_branch.condition, single_branch.address, single_branch.kill, + single_branch.is_sync, single_branch.is_brk, single_branch.ignore); return {ParseResult::ControlCaught, parse_info}; } case OpCode::Id::SYNC: { const auto pred_index = static_cast(instr.pred.pred_index); - parse_info.branch_info.condition.predicate = - GetPredicate(pred_index, instr.negate_pred != 0); - if (parse_info.branch_info.condition.predicate == Pred::NeverExecute) { + single_branch.condition.predicate = GetPredicate(pred_index, instr.negate_pred != 0); + if (single_branch.condition.predicate == Pred::NeverExecute) { offset++; continue; } const ConditionCode cc = instr.flow_condition_code; - parse_info.branch_info.condition.cc = cc; + single_branch.condition.cc = cc; if (cc == ConditionCode::F) { offset++; continue; } - parse_info.branch_info.address = unassigned_branch; - parse_info.branch_info.kill = false; - parse_info.branch_info.is_sync = true; - parse_info.branch_info.is_brk = false; - parse_info.branch_info.ignore = false; + single_branch.address = unassigned_branch; + single_branch.kill = false; + single_branch.is_sync = true; + single_branch.is_brk = false; + single_branch.ignore = false; parse_info.end_address = offset; + parse_info.branch_info = MakeBranchInfo( + single_branch.condition, single_branch.address, single_branch.kill, + single_branch.is_sync, single_branch.is_brk, single_branch.ignore); return {ParseResult::ControlCaught, parse_info}; } case OpCode::Id::BRK: { const auto pred_index = static_cast(instr.pred.pred_index); - parse_info.branch_info.condition.predicate = - GetPredicate(pred_index, instr.negate_pred != 0); - if (parse_info.branch_info.condition.predicate == Pred::NeverExecute) { + single_branch.condition.predicate = GetPredicate(pred_index, instr.negate_pred != 0); + if (single_branch.condition.predicate == Pred::NeverExecute) { offset++; continue; } const ConditionCode cc = instr.flow_condition_code; - parse_info.branch_info.condition.cc = cc; + single_branch.condition.cc = cc; if (cc == ConditionCode::F) { offset++; continue; } - parse_info.branch_info.address = unassigned_branch; - parse_info.branch_info.kill = false; - parse_info.branch_info.is_sync = false; - parse_info.branch_info.is_brk = true; - parse_info.branch_info.ignore = false; + single_branch.address = unassigned_branch; + single_branch.kill = false; + single_branch.is_sync = false; + single_branch.is_brk = true; + single_branch.ignore = false; parse_info.end_address = offset; + parse_info.branch_info = MakeBranchInfo( + single_branch.condition, single_branch.address, single_branch.kill, + single_branch.is_sync, single_branch.is_brk, single_branch.ignore); return {ParseResult::ControlCaught, parse_info}; } case OpCode::Id::KIL: { const auto pred_index = static_cast(instr.pred.pred_index); - parse_info.branch_info.condition.predicate = - GetPredicate(pred_index, instr.negate_pred != 0); - if (parse_info.branch_info.condition.predicate == Pred::NeverExecute) { + single_branch.condition.predicate = GetPredicate(pred_index, instr.negate_pred != 0); + if (single_branch.condition.predicate == Pred::NeverExecute) { offset++; continue; } const ConditionCode cc = instr.flow_condition_code; - parse_info.branch_info.condition.cc = cc; + single_branch.condition.cc = cc; if (cc == ConditionCode::F) { offset++; continue; } - parse_info.branch_info.address = exit_branch; - parse_info.branch_info.kill = true; - parse_info.branch_info.is_sync = false; - parse_info.branch_info.is_brk = false; - parse_info.branch_info.ignore = false; + single_branch.address = exit_branch; + single_branch.kill = true; + single_branch.is_sync = false; + single_branch.is_brk = false; + single_branch.ignore = false; parse_info.end_address = offset; + parse_info.branch_info = MakeBranchInfo( + single_branch.condition, single_branch.address, single_branch.kill, + single_branch.is_sync, single_branch.is_brk, single_branch.ignore); return {ParseResult::ControlCaught, parse_info}; } @@ -407,16 +429,25 @@ std::pair ParseCode(CFGRebuildState& state, u32 address) auto tmp = TrackBranchIndirectInfo(state, address, offset); if (tmp) { auto result = *tmp; - std::string entries{}; + std::vector branches{}; + s32 pc_target = offset + result.relative_position; for (u32 i = 0; i < result.entries; i++) { - auto k = locker.ObtainKey(result.buffer, result.offset + i * 4); - entries = entries + std::to_string(*k) + '\n'; + auto k = state.locker.ObtainKey(result.buffer, result.offset + i * 4); + if (!k) { + return {ParseResult::AbnormalFlow, parse_info}; + } + u32 value = *k; + u32 target = static_cast((value >> 3) + pc_target); + insert_label(state, target); + branches.emplace_back(value, target); } - LOG_CRITICAL(HW_GPU, - "Track Successful, BRX: buffer:{}, offset:{}, entries:{}, inner:\n{}", - result.buffer, result.offset, result.entries, entries); + parse_info.end_address = offset; + parse_info.branch_info = + MakeBranchInfo(static_cast(instr.gpr8.Value()), branches); + + return {ParseResult::ControlCaught, parse_info}; } else { - LOG_CRITICAL(HW_GPU, "Track Unsuccesful"); + LOG_WARNING(HW_GPU, "BRX Track Unsuccesful"); } return {ParseResult::AbnormalFlow, parse_info}; } @@ -426,10 +457,13 @@ std::pair ParseCode(CFGRebuildState& state, u32 address) offset++; } - parse_info.branch_info.kill = false; - parse_info.branch_info.is_sync = false; - parse_info.branch_info.is_brk = false; + single_branch.kill = false; + single_branch.is_sync = false; + single_branch.is_brk = false; parse_info.end_address = offset - 1; + parse_info.branch_info = MakeBranchInfo( + single_branch.condition, single_branch.address, single_branch.kill, single_branch.is_sync, + single_branch.is_brk, single_branch.ignore); return {ParseResult::BlockEnd, parse_info}; } @@ -453,9 +487,10 @@ bool TryInspectAddress(CFGRebuildState& state) { BlockInfo& current_block = state.block_info[block_index]; current_block.end = address - 1; new_block.branch = current_block.branch; - BlockBranchInfo forward_branch{}; - forward_branch.address = address; - forward_branch.ignore = true; + BlockBranchInfo forward_branch = MakeBranchInfo(); + auto branch = std::get_if(forward_branch.get()); + branch->address = address; + branch->ignore = true; current_block.branch = forward_branch; return true; } @@ -470,12 +505,15 @@ bool TryInspectAddress(CFGRebuildState& state) { BlockInfo& block_info = CreateBlockInfo(state, address, parse_info.end_address); block_info.branch = parse_info.branch_info; - if (parse_info.branch_info.condition.IsUnconditional()) { + if (std::holds_alternative(*block_info.branch)) { + auto branch = std::get_if(block_info.branch.get()); + if (branch->condition.IsUnconditional()) { + return true; + } + const u32 fallthrough_address = parse_info.end_address + 1; + state.inspect_queries.push_front(fallthrough_address); return true; } - - const u32 fallthrough_address = parse_info.end_address + 1; - state.inspect_queries.push_front(fallthrough_address); return true; } @@ -513,31 +551,41 @@ bool TryQuery(CFGRebuildState& state) { state.queries.pop_front(); gather_labels(q2.ssy_stack, state.ssy_labels, block); gather_labels(q2.pbk_stack, state.pbk_labels, block); - if (!block.branch.condition.IsUnconditional()) { - q2.address = block.end + 1; - state.queries.push_back(q2); - } + if (std::holds_alternative(*block.branch)) { + auto branch = std::get_if(block.branch.get()); + if (!branch->condition.IsUnconditional()) { + q2.address = block.end + 1; + state.queries.push_back(q2); + } - Query conditional_query{q2}; - if (block.branch.is_sync) { - if (block.branch.address == unassigned_branch) { - block.branch.address = conditional_query.ssy_stack.top(); + Query conditional_query{q2}; + if (branch->is_sync) { + if (branch->address == unassigned_branch) { + branch->address = conditional_query.ssy_stack.top(); + } + conditional_query.ssy_stack.pop(); } - conditional_query.ssy_stack.pop(); - } - if (block.branch.is_brk) { - if (block.branch.address == unassigned_branch) { - block.branch.address = conditional_query.pbk_stack.top(); + if (branch->is_brk) { + if (branch->address == unassigned_branch) { + branch->address = conditional_query.pbk_stack.top(); + } + conditional_query.pbk_stack.pop(); } - conditional_query.pbk_stack.pop(); + conditional_query.address = branch->address; + state.queries.push_back(std::move(conditional_query)); + return true; + } + auto multi_branch = std::get_if(block.branch.get()); + for (auto& branch_case : multi_branch->branches) { + Query conditional_query{q2}; + conditional_query.address = branch_case.address; + state.queries.push_back(std::move(conditional_query)); } - conditional_query.address = block.branch.address; - state.queries.push_back(std::move(conditional_query)); return true; } } // Anonymous namespace -void InsertBranch(ASTManager& mm, const BlockBranchInfo& branch) { +void InsertBranch(ASTManager& mm, const BlockBranchInfo& branch_info) { const auto get_expr = ([&](const Condition& cond) -> Expr { Expr result{}; if (cond.cc != ConditionCode::T) { @@ -564,15 +612,24 @@ void InsertBranch(ASTManager& mm, const BlockBranchInfo& branch) { } return MakeExpr(true); }); - if (branch.address < 0) { - if (branch.kill) { - mm.InsertReturn(get_expr(branch.condition), true); + if (std::holds_alternative(*branch_info)) { + auto branch = std::get_if(branch_info.get()); + if (branch->address < 0) { + if (branch->kill) { + mm.InsertReturn(get_expr(branch->condition), true); + return; + } + mm.InsertReturn(get_expr(branch->condition), false); return; } - mm.InsertReturn(get_expr(branch.condition), false); + mm.InsertGoto(get_expr(branch->condition), branch->address); return; } - mm.InsertGoto(get_expr(branch.condition), branch.address); + auto multi_branch = std::get_if(branch_info.get()); + for (auto& branch_case : multi_branch->branches) { + mm.InsertGoto(MakeExpr(multi_branch->gpr, branch_case.cmp_value), + branch_case.address); + } } void DecompileShader(CFGRebuildState& state) { @@ -584,9 +641,10 @@ void DecompileShader(CFGRebuildState& state) { if (state.labels.count(block.start) != 0) { state.manager->InsertLabel(block.start); } - u32 end = block.branch.ignore ? block.end + 1 : block.end; + const bool ignore = BlockBranchIsIgnored(block.branch); + u32 end = ignore ? block.end + 1 : block.end; state.manager->InsertBlock(block.start, end); - if (!block.branch.ignore) { + if (!ignore) { InsertBranch(*state.manager, block.branch); } } @@ -668,11 +726,9 @@ std::unique_ptr ScanFlow(const ProgramCode& program_code, ShaderBlock new_block{}; new_block.start = block.start; new_block.end = block.end; - new_block.ignore_branch = block.branch.ignore; + new_block.ignore_branch = BlockBranchIsIgnored(block.branch); if (!new_block.ignore_branch) { - new_block.branch.cond = block.branch.condition; - new_block.branch.kills = block.branch.kill; - new_block.branch.address = block.branch.address; + new_block.branch = block.branch; } result_out->end = std::max(result_out->end, block.end); result_out->blocks.push_back(new_block); diff --git a/src/video_core/shader/control_flow.h b/src/video_core/shader/control_flow.h index 6d0e50d7c..369ca255b 100644 --- a/src/video_core/shader/control_flow.h +++ b/src/video_core/shader/control_flow.h @@ -7,6 +7,7 @@ #include #include #include +#include #include "video_core/engines/shader_bytecode.h" #include "video_core/shader/ast.h" @@ -37,29 +38,57 @@ struct Condition { } }; +class SingleBranch { +public: + SingleBranch() = default; + SingleBranch(Condition condition, s32 address, bool kill, bool is_sync, bool is_brk, + bool ignore) + : condition{condition}, address{address}, kill{kill}, is_sync{is_sync}, is_brk{is_brk}, + ignore{ignore} {} + + bool operator==(const SingleBranch& b) const { + return std::tie(condition, address, kill, is_sync, is_brk, ignore) == + std::tie(b.condition, b.address, b.kill, b.is_sync, b.is_brk, b.ignore); + } + + Condition condition{}; + s32 address{exit_branch}; + bool kill{}; + bool is_sync{}; + bool is_brk{}; + bool ignore{}; +}; + +struct CaseBranch { + CaseBranch(u32 cmp_value, u32 address) : cmp_value{cmp_value}, address{address} {} + u32 cmp_value; + u32 address; +}; + +class MultiBranch { +public: + MultiBranch(u32 gpr, std::vector& branches) + : gpr{gpr}, branches{std::move(branches)} {} + + u32 gpr{}; + std::vector branches{}; +}; + +using BranchData = std::variant; +using BlockBranchInfo = std::shared_ptr; + +bool BlockBranchInfoAreEqual(BlockBranchInfo first, BlockBranchInfo second); + struct ShaderBlock { - struct Branch { - Condition cond{}; - bool kills{}; - s32 address{}; - - bool operator==(const Branch& b) const { - return std::tie(cond, kills, address) == std::tie(b.cond, b.kills, b.address); - } - - bool operator!=(const Branch& b) const { - return !operator==(b); - } - }; - u32 start{}; u32 end{}; bool ignore_branch{}; - Branch branch{}; + BlockBranchInfo branch{}; bool operator==(const ShaderBlock& sb) const { - return std::tie(start, end, ignore_branch, branch) == - std::tie(sb.start, sb.end, sb.ignore_branch, sb.branch); + return std::tie(start, end, ignore_branch) == + std::tie(sb.start, sb.end, sb.ignore_branch) && + BlockBranchInfoAreEqual(branch, sb.branch); } bool operator!=(const ShaderBlock& sb) const { diff --git a/src/video_core/shader/decode.cpp b/src/video_core/shader/decode.cpp index 3f87b87ca..053241128 100644 --- a/src/video_core/shader/decode.cpp +++ b/src/video_core/shader/decode.cpp @@ -198,24 +198,38 @@ void ShaderIR::InsertControlFlow(NodeBlock& bb, const ShaderBlock& block) { } return result; }; - if (block.branch.address < 0) { - if (block.branch.kills) { - Node n = Operation(OperationCode::Discard); - n = apply_conditions(block.branch.cond, n); + if (std::holds_alternative(*block.branch)) { + auto branch = std::get_if(block.branch.get()); + if (branch->address < 0) { + if (branch->kill) { + Node n = Operation(OperationCode::Discard); + n = apply_conditions(branch->condition, n); + bb.push_back(n); + global_code.push_back(n); + return; + } + Node n = Operation(OperationCode::Exit); + n = apply_conditions(branch->condition, n); bb.push_back(n); global_code.push_back(n); return; } - Node n = Operation(OperationCode::Exit); - n = apply_conditions(block.branch.cond, n); + Node n = Operation(OperationCode::Branch, Immediate(branch->address)); + n = apply_conditions(branch->condition, n); bb.push_back(n); global_code.push_back(n); return; } - Node n = Operation(OperationCode::Branch, Immediate(block.branch.address)); - n = apply_conditions(block.branch.cond, n); - bb.push_back(n); - global_code.push_back(n); + auto multi_branch = std::get_if(block.branch.get()); + Node op_a = GetRegister(multi_branch->gpr); + for (auto& branch_case : multi_branch->branches) { + Node n = Operation(OperationCode::Branch, Immediate(branch_case.address)); + Node op_b = Immediate(branch_case.cmp_value); + Node condition = GetPredicateComparisonInteger(Tegra::Shader::PredCondition::Equal, false, op_a, op_b); + auto result = Conditional(condition, {n}); + bb.push_back(result); + global_code.push_back(result); + } } u32 ShaderIR::DecodeInstr(NodeBlock& bb, u32 pc) { diff --git a/src/video_core/shader/expr.h b/src/video_core/shader/expr.h index d3dcd00ec..e41d23e93 100644 --- a/src/video_core/shader/expr.h +++ b/src/video_core/shader/expr.h @@ -17,13 +17,14 @@ using Tegra::Shader::Pred; class ExprAnd; class ExprBoolean; class ExprCondCode; +class ExprGprEqual; class ExprNot; class ExprOr; class ExprPredicate; class ExprVar; -using ExprData = - std::variant; +using ExprData = std::variant; using Expr = std::shared_ptr; class ExprAnd final { @@ -118,6 +119,18 @@ public: bool value; }; +class ExprGprEqual final { +public: + ExprGprEqual(u32 gpr, u32 value) : gpr{gpr}, value{value} {} + + bool operator==(const ExprGprEqual& b) const { + return gpr == b.gpr && value == b.value; + } + + u32 gpr; + u32 value; +}; + template Expr MakeExpr(Args&&... args) { static_assert(std::is_convertible_v);