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Diffstat (limited to 'Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs')
-rw-r--r--Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs64
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;
+ }
+ }
+} \ No newline at end of file