suyu/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp

146 lines
4.5 KiB
C++

// Copyright 2021 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <type_traits>
#include "common/bit_util.h"
#include "shader_recompiler/exception.h"
#include "shader_recompiler/frontend/ir/microinstruction.h"
#include "shader_recompiler/ir_opt/passes.h"
namespace Shader::Optimization {
namespace {
[[nodiscard]] u32 BitFieldUExtract(u32 base, u32 shift, u32 count) {
if (static_cast<size_t>(shift) + static_cast<size_t>(count) > Common::BitSize<u32>()) {
throw LogicError("Undefined result in BitFieldUExtract({}, {}, {})", base, shift, count);
}
return (base >> shift) & ((1U << count) - 1);
}
template <typename T>
[[nodiscard]] T Arg(const IR::Value& value) {
if constexpr (std::is_same_v<T, bool>) {
return value.U1();
} else if constexpr (std::is_same_v<T, u32>) {
return value.U32();
} else if constexpr (std::is_same_v<T, u64>) {
return value.U64();
}
}
template <typename ImmFn>
bool FoldCommutative(IR::Inst& inst, ImmFn&& imm_fn) {
const auto arg = [](const IR::Value& value) {
if constexpr (std::is_invocable_r_v<bool, ImmFn, bool, bool>) {
return value.U1();
} else if constexpr (std::is_invocable_r_v<u32, ImmFn, u32, u32>) {
return value.U32();
} else if constexpr (std::is_invocable_r_v<u64, ImmFn, u64, u64>) {
return value.U64();
}
};
const IR::Value lhs{inst.Arg(0)};
const IR::Value rhs{inst.Arg(1)};
const bool is_lhs_immediate{lhs.IsImmediate()};
const bool is_rhs_immediate{rhs.IsImmediate()};
if (is_lhs_immediate && is_rhs_immediate) {
const auto result{imm_fn(arg(lhs), arg(rhs))};
inst.ReplaceUsesWith(IR::Value{result});
return false;
}
if (is_lhs_immediate && !is_rhs_immediate) {
IR::Inst* const rhs_inst{rhs.InstRecursive()};
if (rhs_inst->Opcode() == inst.Opcode() && rhs_inst->Arg(1).IsImmediate()) {
const auto combined{imm_fn(arg(lhs), arg(rhs_inst->Arg(1)))};
inst.SetArg(0, rhs_inst->Arg(0));
inst.SetArg(1, IR::Value{combined});
} else {
// Normalize
inst.SetArg(0, rhs);
inst.SetArg(1, lhs);
}
}
if (!is_lhs_immediate && is_rhs_immediate) {
const IR::Inst* const lhs_inst{lhs.InstRecursive()};
if (lhs_inst->Opcode() == inst.Opcode() && lhs_inst->Arg(1).IsImmediate()) {
const auto combined{imm_fn(arg(rhs), arg(lhs_inst->Arg(1)))};
inst.SetArg(0, lhs_inst->Arg(0));
inst.SetArg(1, IR::Value{combined});
}
}
return true;
}
void FoldGetRegister(IR::Inst& inst) {
if (inst.Arg(0).Reg() == IR::Reg::RZ) {
inst.ReplaceUsesWith(IR::Value{u32{0}});
}
}
void FoldGetPred(IR::Inst& inst) {
if (inst.Arg(0).Pred() == IR::Pred::PT) {
inst.ReplaceUsesWith(IR::Value{true});
}
}
template <typename T>
void FoldAdd(IR::Inst& inst) {
if (inst.HasAssociatedPseudoOperation()) {
return;
}
if (!FoldCommutative(inst, [](T a, T b) { return a + b; })) {
return;
}
const IR::Value rhs{inst.Arg(1)};
if (rhs.IsImmediate() && Arg<T>(rhs) == 0) {
inst.ReplaceUsesWith(inst.Arg(0));
}
}
void FoldLogicalAnd(IR::Inst& inst) {
if (!FoldCommutative(inst, [](bool a, bool b) { return a && b; })) {
return;
}
const IR::Value rhs{inst.Arg(1)};
if (rhs.IsImmediate()) {
if (rhs.U1()) {
inst.ReplaceUsesWith(inst.Arg(0));
} else {
inst.ReplaceUsesWith(IR::Value{false});
}
}
}
void ConstantPropagation(IR::Inst& inst) {
switch (inst.Opcode()) {
case IR::Opcode::GetRegister:
return FoldGetRegister(inst);
case IR::Opcode::GetPred:
return FoldGetPred(inst);
case IR::Opcode::IAdd32:
return FoldAdd<u32>(inst);
case IR::Opcode::IAdd64:
return FoldAdd<u64>(inst);
case IR::Opcode::BitFieldUExtract:
if (inst.AreAllArgsImmediates() && !inst.HasAssociatedPseudoOperation()) {
inst.ReplaceUsesWith(IR::Value{
BitFieldUExtract(inst.Arg(0).U32(), inst.Arg(1).U32(), inst.Arg(2).U32())});
}
break;
case IR::Opcode::LogicalAnd:
return FoldLogicalAnd(inst);
default:
break;
}
}
} // Anonymous namespace
void ConstantPropagationPass(IR::Block& block) {
std::ranges::for_each(block, ConstantPropagation);
}
} // namespace Shader::Optimization