Ryujinx/Ryujinx.Graphics.Shader/Translation/Optimizations/Simplification.cs
2020-01-09 02:13:00 +01:00

147 lines
No EOL
4.6 KiB
C#

using Ryujinx.Graphics.Shader.IntermediateRepresentation;
using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
namespace Ryujinx.Graphics.Shader.Translation.Optimizations
{
static class Simplification
{
private const int AllOnes = ~0;
public static void RunPass(Operation operation)
{
switch (operation.Inst)
{
case Instruction.Add:
case Instruction.BitwiseExclusiveOr:
TryEliminateBinaryOpCommutative(operation, 0);
break;
case Instruction.BitwiseAnd:
TryEliminateBitwiseAnd(operation);
break;
case Instruction.BitwiseOr:
TryEliminateBitwiseOr(operation);
break;
case Instruction.ConditionalSelect:
TryEliminateConditionalSelect(operation);
break;
case Instruction.Divide:
TryEliminateBinaryOpY(operation, 1);
break;
case Instruction.Multiply:
TryEliminateBinaryOpCommutative(operation, 1);
break;
case Instruction.ShiftLeft:
case Instruction.ShiftRightS32:
case Instruction.ShiftRightU32:
case Instruction.Subtract:
TryEliminateBinaryOpY(operation, 0);
break;
}
}
private static void TryEliminateBitwiseAnd(Operation operation)
{
// Try to recognize and optimize those 3 patterns (in order):
// x & 0xFFFFFFFF == x, 0xFFFFFFFF & y == y,
// x & 0x00000000 == 0x00000000, 0x00000000 & y == 0x00000000
Operand x = operation.GetSource(0);
Operand y = operation.GetSource(1);
if (IsConstEqual(x, AllOnes))
{
operation.TurnIntoCopy(y);
}
else if (IsConstEqual(y, AllOnes))
{
operation.TurnIntoCopy(x);
}
else if (IsConstEqual(x, 0) || IsConstEqual(y, 0))
{
operation.TurnIntoCopy(Const(0));
}
}
private static void TryEliminateBitwiseOr(Operation operation)
{
// Try to recognize and optimize those 3 patterns (in order):
// x | 0x00000000 == x, 0x00000000 | y == y,
// x | 0xFFFFFFFF == 0xFFFFFFFF, 0xFFFFFFFF | y == 0xFFFFFFFF
Operand x = operation.GetSource(0);
Operand y = operation.GetSource(1);
if (IsConstEqual(x, 0))
{
operation.TurnIntoCopy(y);
}
else if (IsConstEqual(y, 0))
{
operation.TurnIntoCopy(x);
}
else if (IsConstEqual(x, AllOnes) || IsConstEqual(y, AllOnes))
{
operation.TurnIntoCopy(Const(AllOnes));
}
}
private static void TryEliminateBinaryOpY(Operation operation, int comparand)
{
Operand x = operation.GetSource(0);
Operand y = operation.GetSource(1);
if (IsConstEqual(y, comparand))
{
operation.TurnIntoCopy(x);
}
}
private static void TryEliminateBinaryOpCommutative(Operation operation, int comparand)
{
Operand x = operation.GetSource(0);
Operand y = operation.GetSource(1);
if (IsConstEqual(x, comparand))
{
operation.TurnIntoCopy(y);
}
else if (IsConstEqual(y, comparand))
{
operation.TurnIntoCopy(x);
}
}
private static void TryEliminateConditionalSelect(Operation operation)
{
Operand cond = operation.GetSource(0);
if (cond.Type != OperandType.Constant)
{
return;
}
// The condition is constant, we can turn it into a copy, and select
// the source based on the condition value.
int srcIndex = cond.Value != 0 ? 1 : 2;
Operand source = operation.GetSource(srcIndex);
operation.TurnIntoCopy(source);
}
private static bool IsConstEqual(Operand operand, int comparand)
{
if (operand.Type != OperandType.Constant)
{
return false;
}
return operand.Value == comparand;
}
}
}