[Clang] Accept and forward -fconvergent-functions in the driver

Currently the `-fconvergent-functions` option is primarily used by GPU toolchains to enforce convergent operations in line with the semantics. This option previously was only supported via `-Xclang` and would show up as unused if passed to the driver. This patch allows the driver to forward it. This is mostly useful for users wishing to target GPU toolchains directly via `--target=` without an offloading runtime. Reviewed By: JonChesterfield, MaskRay Differential Revision: https://reviews.llvm.org/D149019
llvm · Apr 24, 2023 · f665760 · f665760
1 parent 8fa0cfe
commit f665760
Show file tree

Hide file tree

Showing 4 changed files with 11 additions and 7 deletions.
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -967,8 +967,10 @@ def cxx_isystem : JoinedOrSeparate<["-"], "cxx-isystem">, Group<clang_i_Group>,
   MetaVarName<"<directory>">;
 def c : Flag<["-"], "c">, Flags<[NoXarchOption, FlangOption]>, Group<Action_Group>,
   HelpText<"Only run preprocess, compile, and assemble steps">;
-def fconvergent_functions : Flag<["-"], "fconvergent-functions">, Group<f_Group>, Flags<[CC1Option]>,
-  HelpText<"Assume functions may be convergent">;
+defm convergent_functions : BoolFOption<"convergent-functions",
+  LangOpts<"ConvergentFunctions">, DefaultFalse,
+  NegFlag<SetFalse, [], "Assume all functions may be convergent.">,
+  PosFlag<SetTrue, [CC1Option]>>;
 
 def gpu_use_aux_triple_only : Flag<["--"], "gpu-use-aux-triple-only">,
   InternalDriverOpt, HelpText<"Prepare '-aux-triple' only without populating "

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5700,6 +5700,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                     options::OPT_fno_unique_internal_linkage_names);
   Args.addOptInFlag(CmdArgs, options::OPT_funique_basic_block_section_names,
                     options::OPT_fno_unique_basic_block_section_names);
+  Args.addOptInFlag(CmdArgs, options::OPT_fconvergent_functions,
+                    options::OPT_fno_convergent_functions);
 
   if (Arg *A = Args.getLastArg(options::OPT_fsplit_machine_functions,
                                options::OPT_fno_split_machine_functions)) {

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3731,9 +3731,9 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.Blocks = Args.hasArg(OPT_fblocks) || (Opts.OpenCL
     && Opts.OpenCLVersion == 200);
 
-  Opts.ConvergentFunctions = Opts.OpenCL || (Opts.CUDA && Opts.CUDAIsDevice) ||
-                             Opts.SYCLIsDevice ||
-                             Args.hasArg(OPT_fconvergent_functions);
+  Opts.ConvergentFunctions = Args.hasArg(OPT_fconvergent_functions) ||
+                             Opts.OpenCL || (Opts.CUDA && Opts.CUDAIsDevice) ||
+                             Opts.SYCLIsDevice;
 
   Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
   if (!Opts.NoBuiltin)

diff --git a/clang/test/Driver/amdgpu-toolchain.c b/clang/test/Driver/amdgpu-toolchain.c
@@ -11,6 +11,6 @@
 // DWARF_VER: "-dwarf-version=5"
 
 // RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx906 -nogpulib \
-// RUN:   -flto %s 2>&1 | FileCheck -check-prefix=LTO %s
-// LTO: clang{{.*}} "-flto=full"
+// RUN:   -flto -fconvergent-functions %s 2>&1 | FileCheck -check-prefix=LTO %s
+// LTO: clang{{.*}} "-flto=full"{{.*}}"-fconvergent-functions"
 // LTO: ld.lld{{.*}}-plugin-opt=mcpu=gfx906