[clang] Remove -Wexperimental-float-control.

Summary: Per D62731, the behavior of clang with `-frounding-math` is no worse than when the rounding flag was completely ignored, so remove this unnecessary warning.

Reviewers: mibintc, chandlerc, echristo, rjmccall, kpn, erichkeane, rsmith, andrew.w.kaylor

Reviewed By: mibintc

Subscribers: merge_guards_bot, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D71671

Author: rupprecht

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -441,10 +441,6 @@ def warn_drv_experimental_isel_incomplete_opt : Warning<
   "-fexperimental-isel support is incomplete for this architecture at the current optimization level">,
   InGroup<ExperimentalISel>;
 
-def warn_drv_experimental_fp_control_incomplete_opt : Warning<
-  "Support for floating point control option %0 is incomplete and experimental">,
-  InGroup<ExperimentalFloatControl>;
-
 def warn_drv_moutline_unsupported_opt : Warning<
   "The '%0' architecture does not support -moutline; flag ignored">,
   InGroup<OptionIgnored>;

clang/include/clang/Basic/DiagnosticGroups.td

@@ -1137,9 +1137,6 @@ def SpirCompat : DiagGroup<"spir-compat">;
 // Warning for the experimental-isel options.
 def ExperimentalISel : DiagGroup<"experimental-isel">;
 
-// Warning for the experimental float control options.
-def ExperimentalFloatControl : DiagGroup<"experimental-float-control">;
-
 // A warning group specifically for warnings related to function
 // multiversioning.
 def FunctionMultiVersioning : DiagGroup<"function-multiversion">;

clang/lib/Driver/ToolChains/Clang.cpp

@@ -2440,15 +2440,7 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     switch (optID) {
     default:
       break;
-    case options::OPT_frounding_math:
-    case options::OPT_ftrapping_math:
-    case options::OPT_ffp_exception_behavior_EQ:
-      D.Diag(clang::diag::warn_drv_experimental_fp_control_incomplete_opt)
-          << A->getOption().getName();
-      break;
     case options::OPT_ffp_model_EQ: {
-      D.Diag(clang::diag::warn_drv_experimental_fp_control_incomplete_opt)
-          << A->getOption().getName();
       // If -ffp-model= is seen, reset to fno-fast-math
       HonorINFs = true;
       HonorNaNs = true;