FP LangOpts should not be dependent on CGOpts

[mibintc]

Summary

This bug was observed by Apple since their compiler processes LangOpts and CGOpts in a different order

[rjmccall]

Thanks, Melanie.

[plotfi]

@mibintc Nice solution. I think this would work.

clang/lib/Frontend/CompilerInvocation.cpp

static const StringRef GetInputKindName(InputKind IK) {
   case Language::Unknown:
     break;
   }
   llvm_unreachable("unknown input language");
 }
 
 static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                           const TargetOptions &TargetOpts,
-                          PreprocessorOptions &PPOpts, CodeGenOptions &CGOpts,
+                          PreprocessorOptions &PPOpts,
                           DiagnosticsEngine &Diags) {
   // FIXME: Cleanup per-file based stuff.
   LangStandard::Kind LangStd = LangStandard::lang_unspecified;
   if (const Arg *A = Args.getLastArg(OPT_std_EQ)) {
     LangStd = LangStandard::getLangKind(A->getValue());
     if (LangStd == LangStandard::lang_unspecified) {
       Diags.Report(diag::err_drv_invalid_value)
         << A->getAsString(Args) << A->getValue();
+      Args.hasFlag(OPT_frecovery_ast_type, OPT_fno_recovery_ast_type, false);
   Opts.FastMath = Args.hasArg(OPT_ffast_math) ||
       Args.hasArg(OPT_cl_fast_relaxed_math);
   Opts.FiniteMathOnly = Args.hasArg(OPT_ffinite_math_only) ||
       Args.hasArg(OPT_cl_finite_math_only) ||
       Args.hasArg(OPT_cl_fast_relaxed_math);
   Opts.UnsafeFPMath = Args.hasArg(OPT_menable_unsafe_fp_math) ||
                       Args.hasArg(OPT_cl_unsafe_math_optimizations) ||
                       Args.hasArg(OPT_cl_fast_relaxed_math);
-  Opts.AllowFPReassoc = Opts.FastMath || CGOpts.Reassociate;
-  Opts.NoHonorNaNs =
-      Opts.FastMath || CGOpts.NoNaNsFPMath || Opts.FiniteMathOnly;
-  Opts.NoHonorInfs =
-      Opts.FastMath || CGOpts.NoInfsFPMath || Opts.FiniteMathOnly;
-  Opts.NoSignedZero = Opts.FastMath || CGOpts.NoSignedZeros;
-  Opts.AllowRecip = Opts.FastMath || CGOpts.ReciprocalMath;
+  Opts.AllowFPReassoc = Opts.FastMath || Args.hasArg(OPT_mreassociate);
+  Opts.NoHonorNaNs = Opts.FastMath || Opts.FiniteMathOnly ||
+                     Args.hasArg(OPT_menable_no_nans) ||
+                     Args.hasArg(OPT_cl_unsafe_math_optimizations) ||
+                     Args.hasArg(OPT_cl_finite_math_only) ||
+                     Args.hasArg(OPT_cl_fast_relaxed_math);
+  Opts.NoHonorInfs = Opts.FastMath || Opts.FiniteMathOnly ||
+                     Args.hasArg(OPT_menable_no_infinities) ||
+                     Args.hasArg(OPT_cl_finite_math_only) ||
+                     Args.hasArg(OPT_cl_fast_relaxed_math);
+  Opts.NoSignedZero = Opts.FastMath || (Args.hasArg(OPT_fno_signed_zeros) ||
+                      Args.hasArg(OPT_cl_no_signed_zeros) ||
+                      Args.hasArg(OPT_cl_unsafe_math_optimizations) ||
+                      Args.hasArg(OPT_cl_fast_relaxed_math));
+  Opts.AllowRecip = Opts.FastMath || Args.hasArg(OPT_freciprocal_math);
   // Currently there's no clang option to enable this individually
   Opts.ApproxFunc = Opts.FastMath;
 
   if (Arg *A = Args.getLastArg(OPT_ffp_contract)) {
     StringRef Val = A->getValue();
     if (Val == "fast")
       Opts.setDefaultFPContractMode(LangOptions::FPM_Fast);
     else if (Val == "on")
if (DashX.getFormat() == InputKind::Precompiled ||
     LangOpts.PICLevel = getLastArgIntValue(Args, OPT_pic_level, 0, Diags);
     LangOpts.PIE = Args.hasArg(OPT_pic_is_pie);
     parseSanitizerKinds("-fsanitize=", Args.getAllArgValues(OPT_fsanitize_EQ),
                         Diags, LangOpts.Sanitize);
   } else {
     // Other LangOpts are only initialized when the input is not AST or LLVM IR.
     // FIXME: Should we really be calling this for an Language::Asm input?
     ParseLangArgs(LangOpts, Args, DashX, Res.getTargetOpts(),
-                  Res.getPreprocessorOpts(), Res.getCodeGenOpts(), Diags);
+                  Res.getPreprocessorOpts(), Diags);
     if (Res.getFrontendOpts().ProgramAction == frontend::RewriteObjC)
       LangOpts.ObjCExceptions = 1;
     if (T.isOSDarwin() && DashX.isPreprocessed()) {
       // Supress the darwin-specific 'stdlibcxx-not-found' diagnostic for
       // preprocessed input as we don't expect it to be used with -std=libc++
       // anyway.
       Res.getDiagnosticOpts().Warnings.push_back("no-stdlibcxx-not-found");
     }