Ryujinx/Ryujinx.Graphics.Shader/Translation/Optimizations/Utils.cs

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using Ryujinx.Graphics.Shader.IntermediateRepresentation;
namespace Ryujinx.Graphics.Shader.Translation.Optimizations
{
static class Utils
{
private static Operation FindBranchSource(BasicBlock block)
{
foreach (BasicBlock sourceBlock in block.Predecessors)
{
if (sourceBlock.Operations.Count > 0)
{
if (sourceBlock.GetLastOp() is Operation lastOp && IsConditionalBranch(lastOp.Inst) && sourceBlock.Next == block)
{
return lastOp;
}
}
}
return null;
}
private static bool IsConditionalBranch(Instruction inst)
{
return inst == Instruction.BranchIfFalse || inst == Instruction.BranchIfTrue;
}
private static bool BlockConditionsMatch(BasicBlock currentBlock, BasicBlock queryBlock)
{
// Check if all the conditions for the query block are satisfied by the current block.
// Just checks the top-most conditional for now.
Operation currentBranch = FindBranchSource(currentBlock);
Operation queryBranch = FindBranchSource(queryBlock);
Operand currentCondition = currentBranch?.GetSource(0);
Operand queryCondition = queryBranch?.GetSource(0);
// The condition should be the same operand instance.
return currentBranch != null && queryBranch != null &&
currentBranch.Inst == queryBranch.Inst &&
currentCondition == queryCondition;
}
public static Operand FindLastOperation(Operand source, BasicBlock block)
{
if (source.AsgOp is PhiNode phiNode)
{
// This source can have a different value depending on a previous branch.
// Ensure that conditions met for that branch are also met for the current one.
// Prefer the latest sources for the phi node.
for (int i = phiNode.SourcesCount - 1; i >= 0; i--)
{
BasicBlock phiBlock = phiNode.GetBlock(i);
if (BlockConditionsMatch(block, phiBlock))
{
return phiNode.GetSource(i);
}
}
}
return source;
}
}
}