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author | ReinUsesLisp <reinuseslisp@airmail.cc> | 2021-07-26 09:24:26 +0200 |
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committer | ReinUsesLisp <reinuseslisp@airmail.cc> | 2021-07-26 09:58:02 +0200 |
commit | 66a0cedba39cabba30c756626d7b58bd0e519d8e (patch) | |
tree | 909321c59c4d184391eea2031c0dd8aee61e6b5c /src/shader_recompiler/ir_opt/constant_propagation_pass.cpp | |
parent | shader: Use TryInstRecursive on XMAD multiply folding (diff) | |
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Diffstat (limited to 'src/shader_recompiler/ir_opt/constant_propagation_pass.cpp')
-rw-r--r-- | src/shader_recompiler/ir_opt/constant_propagation_pass.cpp | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp b/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp index 08a06da02..c403a5fae 100644 --- a/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp +++ b/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp @@ -3,6 +3,7 @@ // Refer to the license.txt file included. #include <algorithm> +#include <functional> #include <tuple> #include <type_traits> @@ -88,6 +89,26 @@ bool FoldWhenAllImmediates(IR::Inst& inst, Func&& func) { return true; } +/// Return true when all values in a range are equal +template <typename Range> +bool AreEqual(const Range& range) { + auto resolver{[](const auto& value) { return value.Resolve(); }}; + auto equal{[](const IR::Value& lhs, const IR::Value& rhs) { + if (lhs == rhs) { + return true; + } + // Not equal, but try to match if they read the same constant buffer + if (!lhs.IsImmediate() && !rhs.IsImmediate() && + lhs.Inst()->GetOpcode() == IR::Opcode::GetCbufU32 && + rhs.Inst()->GetOpcode() == IR::Opcode::GetCbufU32 && + lhs.Inst()->Arg(0) == rhs.Inst()->Arg(0) && lhs.Inst()->Arg(1) == rhs.Inst()->Arg(1)) { + return true; + } + return false; + }}; + return std::ranges::adjacent_find(range, std::not_fn(equal), resolver) == std::end(range); +} + void FoldGetRegister(IR::Inst& inst) { if (inst.Arg(0).Reg() == IR::Reg::RZ) { inst.ReplaceUsesWith(IR::Value{u32{0}}); @@ -100,6 +121,157 @@ void FoldGetPred(IR::Inst& inst) { } } +/// Replaces the XMAD pattern generated by an integer FMA +bool FoldXmadMultiplyAdd(IR::Block& block, IR::Inst& inst) { + /* + * We are looking for this specific pattern: + * %6 = BitFieldUExtract %op_b, #0, #16 + * %7 = BitFieldUExtract %op_a', #16, #16 + * %8 = IMul32 %6, %7 + * %10 = BitFieldUExtract %op_a', #0, #16 + * %11 = BitFieldInsert %8, %10, #16, #16 + * %15 = BitFieldUExtract %op_b, #0, #16 + * %16 = BitFieldUExtract %op_a, #0, #16 + * %17 = IMul32 %15, %16 + * %18 = IAdd32 %17, %op_c + * %22 = BitFieldUExtract %op_b, #16, #16 + * %23 = BitFieldUExtract %11, #16, #16 + * %24 = IMul32 %22, %23 + * %25 = ShiftLeftLogical32 %24, #16 + * %26 = ShiftLeftLogical32 %11, #16 + * %27 = IAdd32 %26, %18 + * %result = IAdd32 %25, %27 + * + * And replace it with: + * %temp = IMul32 %op_a, %op_b + * %result = IAdd32 %temp, %op_c + * + * This optimization has been proven safe by Nvidia's compiler logic being reversed. + * (If Nvidia generates this code from 'fma(a, b, c)', we can do the same in the reverse order.) + */ + const IR::Value zero{0u}; + const IR::Value sixteen{16u}; + IR::Inst* const _25{inst.Arg(0).TryInstRecursive()}; + IR::Inst* const _27{inst.Arg(1).TryInstRecursive()}; + if (!_25 || !_27) { + return false; + } + if (_27->GetOpcode() != IR::Opcode::IAdd32) { + return false; + } + if (_25->GetOpcode() != IR::Opcode::ShiftLeftLogical32 || _25->Arg(1) != sixteen) { + return false; + } + IR::Inst* const _24{_25->Arg(0).TryInstRecursive()}; + if (!_24 || _24->GetOpcode() != IR::Opcode::IMul32) { + return false; + } + IR::Inst* const _22{_24->Arg(0).TryInstRecursive()}; + IR::Inst* const _23{_24->Arg(1).TryInstRecursive()}; + if (!_22 || !_23) { + return false; + } + if (_22->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + if (_23->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + if (_22->Arg(1) != sixteen || _22->Arg(2) != sixteen) { + return false; + } + if (_23->Arg(1) != sixteen || _23->Arg(2) != sixteen) { + return false; + } + IR::Inst* const _11{_23->Arg(0).TryInstRecursive()}; + if (!_11 || _11->GetOpcode() != IR::Opcode::BitFieldInsert) { + return false; + } + if (_11->Arg(2) != sixteen || _11->Arg(3) != sixteen) { + return false; + } + IR::Inst* const _8{_11->Arg(0).TryInstRecursive()}; + IR::Inst* const _10{_11->Arg(1).TryInstRecursive()}; + if (!_8 || !_10) { + return false; + } + if (_8->GetOpcode() != IR::Opcode::IMul32) { + return false; + } + if (_10->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + IR::Inst* const _6{_8->Arg(0).TryInstRecursive()}; + IR::Inst* const _7{_8->Arg(1).TryInstRecursive()}; + if (!_6 || !_7) { + return false; + } + if (_6->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + if (_7->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + if (_6->Arg(1) != zero || _6->Arg(2) != sixteen) { + return false; + } + if (_7->Arg(1) != sixteen || _7->Arg(2) != sixteen) { + return false; + } + IR::Inst* const _26{_27->Arg(0).TryInstRecursive()}; + IR::Inst* const _18{_27->Arg(1).TryInstRecursive()}; + if (!_26 || !_18) { + return false; + } + if (_26->GetOpcode() != IR::Opcode::ShiftLeftLogical32 || _26->Arg(1) != sixteen) { + return false; + } + if (_26->Arg(0).InstRecursive() != _11) { + return false; + } + if (_18->GetOpcode() != IR::Opcode::IAdd32) { + return false; + } + IR::Inst* const _17{_18->Arg(0).TryInstRecursive()}; + if (!_17 || _17->GetOpcode() != IR::Opcode::IMul32) { + return false; + } + IR::Inst* const _15{_17->Arg(0).TryInstRecursive()}; + IR::Inst* const _16{_17->Arg(1).TryInstRecursive()}; + if (!_15 || !_16) { + return false; + } + if (_15->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + if (_16->GetOpcode() != IR::Opcode::BitFieldUExtract) { + return false; + } + if (_15->Arg(1) != zero || _16->Arg(1) != zero || _10->Arg(1) != zero) { + return false; + } + if (_15->Arg(2) != sixteen || _16->Arg(2) != sixteen || _10->Arg(2) != sixteen) { + return false; + } + const std::array<IR::Value, 3> op_as{ + _7->Arg(0).Resolve(), + _16->Arg(0).Resolve(), + _10->Arg(0).Resolve(), + }; + const std::array<IR::Value, 3> op_bs{ + _22->Arg(0).Resolve(), + _6->Arg(0).Resolve(), + _15->Arg(0).Resolve(), + }; + const IR::U32 op_c{_18->Arg(1)}; + if (!AreEqual(op_as) || !AreEqual(op_bs)) { + return false; + } + IR::IREmitter ir{block, IR::Block::InstructionList::s_iterator_to(inst)}; + inst.ReplaceUsesWith(ir.IAdd(ir.IMul(IR::U32{op_as[0]}, IR::U32{op_bs[1]}), op_c)); + return true; +} + /// Replaces the pattern generated by two XMAD multiplications bool FoldXmadMultiply(IR::Block& block, IR::Inst& inst) { /* @@ -179,6 +351,9 @@ void FoldAdd(IR::Block& block, IR::Inst& inst) { if (FoldXmadMultiply(block, inst)) { return; } + if (FoldXmadMultiplyAdd(block, inst)) { + return; + } } } |