Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1888,7 +1888,7 @@
 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,
Index: clang/lib/Driver/ToolChains/Flang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Flang.cpp
+++ clang/lib/Driver/ToolChains/Flang.cpp
@@ -88,6 +88,7 @@
   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();
@@ -143,6 +144,12 @@
     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
@@ -166,6 +173,9 @@
 
   if (AssociativeMath && !SignedZeros)
     CmdArgs.push_back("-mreassociate");
+
+  if (ReciprocalMath)
+    CmdArgs.push_back("-freciprocal-math");
 }
 
 void Flang::ConstructJob(Compilation &C, const JobAction &JA,
Index: flang/include/flang/Frontend/LangOptions.def
===================================================================
--- flang/include/flang/Frontend/LangOptions.def
+++ flang/include/flang/Frontend/LangOptions.def
@@ -31,6 +31,8 @@
 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
Index: flang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- flang/lib/Frontend/CompilerInvocation.cpp
+++ flang/lib/Frontend/CompilerInvocation.cpp
@@ -721,6 +721,12 @@
     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;
 }
 
Index: flang/test/Driver/driver-help-hidden.f90
===================================================================
--- flang/test/Driver/driver-help-hidden.f90
+++ flang/test/Driver/driver-help-hidden.f90
@@ -48,6 +48,7 @@
 ! 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
Index: flang/test/Driver/driver-help.f90
===================================================================
--- flang/test/Driver/driver-help.f90
+++ flang/test/Driver/driver-help.f90
@@ -46,6 +46,7 @@
 ! 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
@@ -128,6 +129,7 @@
 ! 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
Index: flang/test/Driver/flang_fp_opts.f90
===================================================================
--- flang/test/Driver/flang_fp_opts.f90
+++ flang/test/Driver/flang_fp_opts.f90
@@ -7,6 +7,7 @@
 ! 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
@@ -14,3 +15,4 @@
 ! 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
Index: flang/test/Driver/frontend-forwarding.f90
===================================================================
--- flang/test/Driver/frontend-forwarding.f90
+++ flang/test/Driver/frontend-forwarding.f90
@@ -14,6 +14,7 @@
 ! RUN:     -fapprox-func \
 ! RUN:     -fno-signed-zeros \
 ! RUN:     -fassociative-math \
+! RUN:     -freciprocal-math \
 ! RUN:     -mllvm -print-before-all\
 ! RUN:     -P \
 ! RUN:   | FileCheck %s
@@ -30,5 +31,6 @@
 ! CHECK: "-fapprox-func"
 ! CHECK: "-fno-signed-zeros"
 ! CHECK: "-mreassociate"
+! CHECK: "-freciprocal-math"
 ! CHECK: "-fconvert=little-endian"
 ! CHECK:  "-mllvm" "-print-before-all"