[flang] Add -f[no-]honor-nans and -menable-no-nans

Only add the option processing and store the result. No attributes are
added to FIR yet.

Differential Revision: https://reviews.llvm.org/D137325

Author: tblah

clang/include/clang/Driver/Options.td

@@ -5444,9 +5444,6 @@ def mframe_pointer_EQ : Joined<["-"], "mframe-pointer=">,
   HelpText<"Specify which frame pointers to retain.">, Values<"all,non-leaf,none">,
   NormalizedValuesScope<"CodeGenOptions::FramePointerKind">, NormalizedValues<["All", "NonLeaf", "None"]>,
   MarshallingInfoEnum<CodeGenOpts<"FramePointer">, "None">;
-def menable_no_nans : Flag<["-"], "menable-no-nans">,
-  HelpText<"Allow optimization to assume there are no NaNs.">,
-  MarshallingInfoFlag<LangOpts<"NoHonorNaNs">>, ImpliedByAnyOf<[ffinite_math_only.KeyPath]>;
 def mreassociate : Flag<["-"], "mreassociate">,
   HelpText<"Allow reassociation transformations for floating-point instructions">,
   MarshallingInfoFlag<LangOpts<"AllowFPReassoc">>, ImpliedByAnyOf<[funsafe_math_optimizations.KeyPath]>;
@@ -6057,6 +6054,9 @@ def split_dwarf_output : Separate<["-"], "split-dwarf-output">,
 
 let Flags = [CC1Option, FC1Option, NoDriverOption] in {
 
+def menable_no_nans : Flag<["-"], "menable-no-nans">,
+  HelpText<"Allow optimization to assume there are no NaNs.">,
+  MarshallingInfoFlag<LangOpts<"NoHonorNaNs">>, ImpliedByAnyOf<[ffinite_math_only.KeyPath]>;
 def menable_no_infinities : Flag<["-"], "menable-no-infs">,
   HelpText<"Allow optimization to assume there are no infinities.">,
   MarshallingInfoFlag<LangOpts<"NoHonorInfs">>, ImpliedByAnyOf<[ffinite_math_only.KeyPath]>;

clang/lib/Driver/ToolChains/Flang.cpp

@@ -84,6 +84,7 @@ static void addFloatingPointOptions(const Driver &D, const ArgList &Args,
                                     ArgStringList &CmdArgs) {
   StringRef FPContract;
   bool HonorINFs = true;
+  bool HonorNaNs = true;
 
   if (const Arg *A = Args.getLastArg(options::OPT_ffp_contract)) {
     const StringRef Val = A->getValue();
@@ -115,6 +116,12 @@ static void addFloatingPointOptions(const Driver &D, const ArgList &Args,
     case options::OPT_fno_honor_infinities:
       HonorINFs = false;
       break;
+    case options::OPT_fhonor_nans:
+      HonorNaNs = true;
+      break;
+    case options::OPT_fno_honor_nans:
+      HonorNaNs = false;
+      break;
     }
 
     // If we handled this option claim it
@@ -126,6 +133,9 @@ static void addFloatingPointOptions(const Driver &D, const ArgList &Args,
 
   if (!HonorINFs)
     CmdArgs.push_back("-menable-no-infs");
+
+  if (!HonorNaNs)
+    CmdArgs.push_back("-menable-no-nans");
 }
 
 void Flang::ConstructJob(Compilation &C, const JobAction &JA,

flang/include/flang/Frontend/LangOptions.def

@@ -23,6 +23,8 @@ ENUM_LANGOPT(FPContractMode, FPModeKind, 2, FPM_Off) ///< FP Contract Mode (off/
 
 /// Permit floating point optimization without regard to infinities
 LANGOPT(NoHonorInfs, 1, false)
+/// Permit floating point optimization without regard to NaN
+LANGOPT(NoHonorNaNs, 1, false)
 
 #undef LANGOPT
 #undef ENUM_LANGOPT

flang/lib/Frontend/CompilerInvocation.cpp

@@ -702,6 +702,12 @@ static bool parseFloatingPointArgs(CompilerInvocation &invoc,
     opts.NoHonorInfs = true;
   }
 
+  if (const llvm::opt::Arg *a =
+          args.getLastArg(clang::driver::options::OPT_menable_no_nans)) {
+    diags.Report(diagUnimplemented) << a->getOption().getName();
+    opts.NoHonorNaNs = true;
+  }
+
   return true;
 }
 

flang/test/Driver/driver-help.f90

@@ -131,6 +131,7 @@
 ! HELP-FC1-NEXT: -I <dir>               Add directory to the end of the list of include search paths
 ! HELP-FC1-NEXT: -load <dsopath>        Load the named plugin (dynamic shared object)
 ! HELP-FC1-NEXT: -menable-no-infs       Allow optimization to assume there are no infinities.
+! HELP-FC1-NEXT: -menable-no-nans       Allow optimization to assume there are no NaNs.
 ! HELP-FC1-NEXT: -mllvm <value>         Additional arguments to forward to LLVM's option processing
 ! HELP-FC1-NEXT: -mmlir <value>         Additional arguments to forward to MLIR's option processing
 ! HELP-FC1-NEXT: -module-dir <dir>      Put MODULE files in <dir>

flang/test/Driver/flang_fp_opts.f90

@@ -1,5 +1,10 @@
 ! Test for handling of floating point options within the frontend driver
 
-! RUN: %flang_fc1 -ffp-contract=fast -menable-no-infs %s 2>&1 | FileCheck %s
+! RUN: %flang_fc1 \
+! RUN:      -ffp-contract=fast \
+! RUN:      -menable-no-infs \
+! RUN:      -menable-no-nans \
+! RUN:      %s 2>&1 | FileCheck %s
 ! CHECK: ffp-contract= is not currently implemented
 ! CHECK: menable-no-infs is not currently implemented
+! CHECK: menable-no-nans is not currently implemented

flang/test/Driver/frontend-forwarding.f90

@@ -10,6 +10,7 @@
 ! RUN:     -fconvert=little-endian \
 ! RUN:     -ffp-contract=fast \
 ! RUN:     -fno-honor-infinities \
+! RUN:     -fno-honor-nans \
 ! RUN:     -mllvm -print-before-all\
 ! RUN:     -P \
 ! RUN:   | FileCheck %s
@@ -22,5 +23,6 @@
 ! CHECK: "-flarge-sizes"
 ! CHECK: "-ffp-contract=fast"
 ! CHECK: "-menable-no-infs"
+! CHECK: "-menable-no-nans"
 ! CHECK: "-fconvert=little-endian"
 ! CHECK:  "-mllvm" "-print-before-all"