[HLSL] Enable -fconvergent-functions by default (#86571)

Fixes  #86506

Author: aniplcc

clang/lib/Frontend/CompilerInvocation.cpp

@@ -3516,7 +3516,8 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
     GenerateArg(Consumer, OPT_fblocks);
 
   if (Opts.ConvergentFunctions &&
-      !(Opts.OpenCL || (Opts.CUDA && Opts.CUDAIsDevice) || Opts.SYCLIsDevice))
+      !(Opts.OpenCL || (Opts.CUDA && Opts.CUDAIsDevice) || Opts.SYCLIsDevice ||
+        Opts.HLSL))
     GenerateArg(Consumer, OPT_fconvergent_functions);
 
   if (Opts.NoBuiltin && !Opts.Freestanding)
@@ -3914,7 +3915,7 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
 
   Opts.ConvergentFunctions = Args.hasArg(OPT_fconvergent_functions) ||
                              Opts.OpenCL || (Opts.CUDA && Opts.CUDAIsDevice) ||
-                             Opts.SYCLIsDevice;
+                             Opts.SYCLIsDevice || Opts.HLSL;
 
   Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
   if (!Opts.NoBuiltin)

clang/test/CodeGenHLSL/convergent-functions.hlsl

@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.4-library -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple spirv-linux-vulkan-library -emit-llvm -disable-llvm-passes -o - %s | FileCheck %s
+
+void fn() {
+};
+
+// CHECK: define{{.*| }}void {{.*}}fn{{.*}}()
+// CHECK-SAME: #[[Attr:[0-9]+]]
+// CHECK: attributes #[[Attr]] = { {{[^}]*}}convergent{{[^}]*}} }