[flang] add -f[no-]reciprocal-math

[tblah]

Summary

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

[kiranchandramohan]

LGTM.

[awarzynski]

LGTM, thanks!

clang/include/clang/Driver/Options.td

def funsafe_math_optimizations : Flag<["-"], "funsafe-math-optimizations">,
   MarshallingInfoFlag<LangOpts<"UnsafeFPMath">>,
   ImpliedByAnyOf<[cl_unsafe_math_optimizations.KeyPath, ffast_math.KeyPath]>;
 def fno_unsafe_math_optimizations : Flag<["-"], "fno-unsafe-math-optimizations">,
   Group<f_Group>;
 def fassociative_math : Flag<["-"], "fassociative-math">, Group<f_Group>;
 def fno_associative_math : Flag<["-"], "fno-associative-math">, Group<f_Group>;
 defm reciprocal_math : BoolFOption<"reciprocal-math",
   LangOpts<"AllowRecip">, DefaultFalse,
-  PosFlag<SetTrue, [CC1Option], "Allow division operations to be reassociated",
+  PosFlag<SetTrue, [CC1Option, FC1Option, FlangOption], "Allow division operations to be reassociated",
           [funsafe_math_optimizations.KeyPath]>,
   NegFlag<SetFalse>>;
 defm approx_func : BoolFOption<"approx-func", LangOpts<"ApproxFunc">, DefaultFalse,
    PosFlag<SetTrue, [CC1Option, FC1Option, FlangOption], "Allow certain math function calls to be replaced "
            "with an approximately equivalent calculation",
            [funsafe_math_optimizations.KeyPath]>,
    NegFlag<SetFalse>>;
 defm finite_math_only : BoolFOption<"finite-math-only",

clang/lib/Driver/ToolChains/Flang.cpp

 static void addFloatingPointOptions(const Driver &D, const ArgList &Args,
                                     ArgStringList &CmdArgs) {
   StringRef FPContract;
   bool HonorINFs = true;
   bool HonorNaNs = true;
   bool ApproxFunc = false;
   bool SignedZeros = true;
   bool AssociativeMath = false;
+  bool ReciprocalMath = false;
 
   if (const Arg *A = Args.getLastArg(options::OPT_ffp_contract)) {
     const StringRef Val = A->getValue();
     if (Val == "fast" || Val == "off") {
       FPContract = Val;
     } else if (Val == "on") {
       // Warn instead of error because users might have makefiles written for
       // gfortran (which accepts -ffp-contract=on)
case options::OPT_fno_signed_zeros:
       SignedZeros = false;
       break;
     case options::OPT_fassociative_math:
       AssociativeMath = true;
       break;
     case options::OPT_fno_associative_math:
       AssociativeMath = false;
       break;
+    case options::OPT_freciprocal_math:
+      ReciprocalMath = true;
+      break;
+    case options::OPT_fno_reciprocal_math:
+      ReciprocalMath = false;
+      break;
     }
 
     // If we handled this option claim it
     A->claim();
   }
 
   if (!FPContract.empty())
     CmdArgs.push_back(Args.MakeArgString("-ffp-contract=" + FPContract));
 
   if (!HonorINFs)
     CmdArgs.push_back("-menable-no-infs");
 
   if (!HonorNaNs)
     CmdArgs.push_back("-menable-no-nans");
 
   if (ApproxFunc)
     CmdArgs.push_back("-fapprox-func");
 
   if (!SignedZeros)
     CmdArgs.push_back("-fno-signed-zeros");
 
   if (AssociativeMath && !SignedZeros)
     CmdArgs.push_back("-mreassociate");
+
+  if (ReciprocalMath)
+    CmdArgs.push_back("-freciprocal-math");
 }
 
 void Flang::ConstructJob(Compilation &C, const JobAction &JA,
                          const InputInfo &Output, const InputInfoList &Inputs,
                          const ArgList &Args, const char *LinkingOutput) const {
   const auto &TC = getToolChain();
   const llvm::Triple &Triple = TC.getEffectiveTriple();
   const std::string &TripleStr = Triple.getTriple();

flang/include/flang/Frontend/LangOptions.def

 /// Permit floating point optimization without regard to NaN
 LANGOPT(NoHonorNaNs, 1, false)
 /// Allow math functions to be replaced with an approximately equivalent calculation
 LANGOPT(ApproxFunc, 1, false)
 /// Allow optimizations that ignore the sign of floating point zeros
 LANGOPT(NoSignedZeros, 1, false)
 /// Allow reassociation transformations for floating-point instructions
 LANGOPT(AssociativeMath, 1, false)
+/// Allow division operations to be reassociated
+LANGOPT(ReciprocalMath, 1, false)
 
 #undef LANGOPT
 #undef ENUM_LANGOPT

flang/lib/Frontend/CompilerInvocation.cpp

static bool parseFloatingPointArgs(CompilerInvocation &invoc,
   }
 
   if (const llvm::opt::Arg *a =
           args.getLastArg(clang::driver::options::OPT_mreassociate)) {
     diags.Report(diagUnimplemented) << a->getOption().getName();
     opts.AssociativeMath = true;
   }
 
+  if (const llvm::opt::Arg *a =
+          args.getLastArg(clang::driver::options::OPT_freciprocal_math)) {
+    diags.Report(diagUnimplemented) << a->getOption().getName();
+    opts.ReciprocalMath = true;
+  }
+
   return true;
 }
 
 bool CompilerInvocation::createFromArgs(
     CompilerInvocation &res, llvm::ArrayRef<const char *> commandLineArgs,
     clang::DiagnosticsEngine &diags) {
 
   bool success = true;

flang/test/Driver/driver-help-hidden.f90

 ! CHECK-NEXT: -flarge-sizes          Use INTEGER(KIND=8) for the result type in size-related intrinsics
 ! CHECK-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! CHECK-NEXT: -fno-automatic         Implies the SAVE attribute for non-automatic local objects in subprograms unless RECURSIVE
 ! CHECK-NEXT: -fno-color-diagnostics  Disable colors in diagnostics
 ! CHECK-NEXT: -fno-integrated-as     Disable the integrated assembler
 ! CHECK-NEXT: -fno-signed-zeros      Allow optimizations that ignore the sign of floating point zeros
 ! CHECK-NEXT: -fopenacc              Enable OpenACC
 ! CHECK-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
+! CHECK-NEXT: -freciprocal-math      Allow division operations to be reassociated
 ! CHECK-NEXT: -fsyntax-only          Run the preprocessor, parser and semantic analysis stages
 ! CHECK-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! CHECK-NEXT: -help     Display available options
 ! CHECK-NEXT: -I <dir>               Add directory to the end of the list of include search paths
 ! CHECK-NEXT: -mllvm <value>         Additional arguments to forward to LLVM's option processing
 ! CHECK-NEXT: -mmlir <value>         Additional arguments to forward to MLIR's option processing
 ! CHECK-NEXT: -module-dir <dir>      Put MODULE files in <dir>
 ! CHECK-NEXT: -nocpp                 Disable predefined and command line preprocessor macros

flang/test/Driver/driver-help.f90

 ! HELP-NEXT: -flarge-sizes          Use INTEGER(KIND=8) for the result type in size-related intrinsics
 ! HELP-NEXT: -flogical-abbreviations Enable logical abbreviations
 ! HELP-NEXT: -fno-automatic         Implies the SAVE attribute for non-automatic local objects in subprograms unless RECURSIVE
 ! HELP-NEXT: -fno-color-diagnostics  Disable colors in diagnostics
 ! HELP-NEXT: -fno-integrated-as      Disable the integrated assembler
 ! HELP-NEXT: -fno-signed-zeros      Allow optimizations that ignore the sign of floating point zeros
 ! HELP-NEXT: -fopenacc              Enable OpenACC
 ! HELP-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
+! HELP-NEXT: -freciprocal-math      Allow division operations to be reassociated
 ! HELP-NEXT: -fsyntax-only          Run the preprocessor, parser and semantic analysis stages
 ! HELP-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! HELP-NEXT: -help                  Display available options
 ! HELP-NEXT: -I <dir>               Add directory to the end of the list of include search paths
 ! HELP-NEXT: -mllvm <value>         Additional arguments to forward to LLVM's option processing
 ! HELP-NEXT: -mmlir <value>         Additional arguments to forward to MLIR's option processing
 ! HELP-NEXT: -module-dir <dir>      Put MODULE files in <dir>
 ! HELP-NEXT: -nocpp                 Disable predefined and command line preprocessor macros

 ! HELP-FC1-NEXT: -fno-analyzed-objects-for-unparse
 ! HELP-FC1-NEXT:                        Do not use the analyzed objects when unparsing
 ! HELP-FC1-NEXT: -fno-automatic         Implies the SAVE attribute for non-automatic local objects in subprograms unless RECURSIVE
 ! HELP-FC1-NEXT: -fno-debug-pass-manager Disables debug printing for the new pass manager
 ! HELP-FC1-NEXT: -fno-reformat          Dump the cooked character stream in -E mode
 ! HELP-FC1-NEXT: -fno-signed-zeros      Allow optimizations that ignore the sign of floating point zeros
 ! HELP-FC1-NEXT: -fopenacc              Enable OpenACC
 ! HELP-FC1-NEXT: -fopenmp               Parse OpenMP pragmas and generate parallel code.
+! HELP-FC1-NEXT: -freciprocal-math      Allow division operations to be reassociated
 ! HELP-FC1-NEXT: -fsyntax-only          Run the preprocessor, parser and semantic analysis stages
 ! HELP-FC1-NEXT: -fxor-operator         Enable .XOR. as a synonym of .NEQV.
 ! HELP-FC1-NEXT: -help                  Display available options
 ! HELP-FC1-NEXT: -init-only             Only execute frontend initialization
 ! 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.

flang/test/Driver/flang_fp_opts.f90

 ! Test for handling of floating point options within the frontend driver
 
 ! RUN: %flang_fc1 \
 ! RUN:      -ffp-contract=fast \
 ! RUN:      -menable-no-infs \
 ! RUN:      -menable-no-nans \
 ! RUN:      -fapprox-func \
 ! RUN:      -fno-signed-zeros \
 ! RUN:      -mreassociate \
+! RUN:      -freciprocal-math \
 ! 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
 ! CHECK: fapprox-func is not currently implemented
 ! CHECK: fno-signed-zeros is not currently implemented
 ! CHECK: mreassociate is not currently implemented
+! CHECK: freciprocal-math is not currently implemented

flang/test/Driver/frontend-forwarding.f90

 ! Test that flang-new forwards Flang frontend
 ! options to flang-new -fc1 as expected.
 
 ! RUN: %flang -fsyntax-only -### %s -o %t 2>&1 \
 ! RUN:     -finput-charset=utf-8 \
 ! RUN:     -fdefault-double-8 \
 ! RUN:     -fdefault-integer-8 \
 ! RUN:     -fdefault-real-8 \
 ! RUN:     -flarge-sizes \
 ! RUN:     -fconvert=little-endian \
 ! RUN:     -ffp-contract=fast \
 ! RUN:     -fno-honor-infinities \
 ! RUN:     -fno-honor-nans \
 ! RUN:     -fapprox-func \
 ! RUN:     -fno-signed-zeros \
 ! RUN:     -fassociative-math \
+! RUN:     -freciprocal-math \
 ! RUN:     -mllvm -print-before-all\
 ! RUN:     -P \
 ! RUN:   | FileCheck %s
 
 ! CHECK: "-P"
 ! CHECK: "-finput-charset=utf-8"
 ! CHECK: "-fdefault-double-8"
 ! CHECK: "-fdefault-integer-8"
 ! CHECK: "-fdefault-real-8"
 ! CHECK: "-flarge-sizes"
 ! CHECK: "-ffp-contract=fast"
 ! CHECK: "-menable-no-infs"
 ! CHECK: "-menable-no-nans"
 ! CHECK: "-fapprox-func"
 ! CHECK: "-fno-signed-zeros"
 ! CHECK: "-mreassociate"
+! CHECK: "-freciprocal-math"
 ! CHECK: "-fconvert=little-endian"
 ! CHECK:  "-mllvm" "-print-before-all"