Remove barrier on Intel if control flow is potentially divergent (#5044)

* Remove barrier on Intel if control flow is potentially divergent

* Shader cache version bump

3 files changed, 19 insertions, 2 deletions

diff --git a/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/CodeGenContext.cs b/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/CodeGenContext.cs
index c1bfa088..1f5167e6 100644
--- a/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/CodeGenContext.cs
+++ b/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/CodeGenContext.cs
@@ -76,6 +76,9 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
 
         public SpirvDelegates Delegates { get; }
 
+        public bool IsMainFunction { get; private set; }
+        public bool MayHaveReturned { get; set; }
+
         public CodeGenContext(
             StructuredProgramInfo info,
             ShaderConfig config,
@@ -108,8 +111,10 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
             Delegates = new SpirvDelegates(this);
         }
 
-        public void StartFunction()
+        public void StartFunction(bool isMainFunction)
         {
+            IsMainFunction = isMainFunction;
+            MayHaveReturned = false;
             _locals.Clear();
             _localForArgs.Clear();
             _funcArgs.Clear();
diff --git a/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/Instructions.cs b/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/Instructions.cs
index 4be0c62b..6c115752 100644
--- a/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/Instructions.cs
+++ b/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/Instructions.cs
@@ -242,6 +242,16 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
 
         private static OperationResult GenerateBarrier(CodeGenContext context, AstOperation operation)
         {
+            // Barrier on divergent control flow paths may cause the GPU to hang,
+            // so skip emitting the barrier for those cases.
+            if (!context.Config.GpuAccessor.QueryHostSupportsShaderBarrierDivergence() &&
+                (context.CurrentBlock.Type != AstBlockType.Main || context.MayHaveReturned || !context.IsMainFunction))
+            {
+                context.Config.GpuAccessor.Log($"Shader has barrier on potentially divergent block, the barrier will be removed.");
+
+                return OperationResult.Invalid;
+            }
+
             context.ControlBarrier(
                 context.Constant(context.TypeU32(), Scope.Workgroup),
                 context.Constant(context.TypeU32(), Scope.Workgroup),
@@ -1092,6 +1102,8 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
 
         private static OperationResult GenerateReturn(CodeGenContext context, AstOperation operation)
         {
+            context.MayHaveReturned = true;
+
             if (operation.SourcesCount != 0)
             {
                 context.ReturnValue(context.Get(context.CurrentFunction.ReturnType, operation.GetSource(0)));
diff --git a/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/SpirvGenerator.cs b/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/SpirvGenerator.cs
index a55e09fd..5c736b60 100644
--- a/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/SpirvGenerator.cs
+++ b/src/Ryujinx.Graphics.Shader/CodeGen/Spirv/SpirvGenerator.cs
@@ -148,7 +148,7 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Spirv
 
             context.CurrentFunction = function;
             context.AddFunction(spvFunc);
-            context.StartFunction();
+            context.StartFunction(isMainFunction: funcIndex == 0);
 
             Declarations.DeclareParameters(context, function);