diff options
Diffstat (limited to 'Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs')
-rw-r--r-- | Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs b/Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs new file mode 100644 index 00000000..2b0f1905 --- /dev/null +++ b/Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs @@ -0,0 +1,64 @@ +using Ryujinx.Graphics.Shader.IntermediateRepresentation; +using System; + +namespace Ryujinx.Graphics.Shader.Translation.Optimizations +{ + static class BranchElimination + { + public static bool Eliminate(BasicBlock block) + { + if (block.HasBranch && IsRedundantBranch((Operation)block.GetLastOp(), Next(block))) + { + block.Branch = null; + + return true; + } + + return false; + } + + private static bool IsRedundantBranch(Operation current, BasicBlock nextBlock) + { + //Here we check that: + //- The current block ends with a branch. + //- The next block only contains a branch. + //- The branch on the next block is unconditional. + //- Both branches are jumping to the same location. + //In this case, the branch on the current block can be removed, + //as the next block is going to jump to the same place anyway. + if (nextBlock == null) + { + return false; + } + + if (!(nextBlock.Operations.First?.Value is Operation next)) + { + return false; + } + + if (next.Inst != Instruction.Branch) + { + return false; + } + + return current.Dest == next.Dest; + } + + private static BasicBlock Next(BasicBlock block) + { + block = block.Next; + + while (block != null && block.Operations.Count == 0) + { + if (block.HasBranch) + { + throw new InvalidOperationException("Found a bogus empty block that \"ends with a branch\"."); + } + + block = block.Next; + } + + return block; + } + } +}
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