Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -6650,6 +6650,9 @@
 def _SLASH_J : CLFlag<"J">, HelpText<"Make char type unsigned">,
   Alias<funsigned_char>;
 
+def _SLASH_fexcess_precision_EQ : CLJoined<"fexcess-precision=">,
+  Alias<fexcess_precision_EQ>;
+
 // The _SLASH_O option handles all the /O flags, but we also provide separate
 // aliased options to provide separate help messages.
 def _SLASH_O : CLDXCJoined<"O">,
Index: clang/test/Driver/cl-options.c
===================================================================
--- clang/test/Driver/cl-options.c
+++ clang/test/Driver/cl-options.c
@@ -233,6 +233,14 @@
 // RUN: %clang_cl /EP /P /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // showIncludes_E-NOT: warning: argument unused during compilation: '--show-includes'
 
+// Floating point excess precision
+// RUN: %clang_cl /fexcess-precision=fast -### -- %s 2>&1 | FileCheck -check-prefix=f16-prec-fast %s
+// f16-prec-fast: -ffloat16-excess-precision=fast
+// RUN: %clang_cl /fexcess-precision=standard -### -- %s 2>&1 | FileCheck -check-prefix=f16-prec-std %s
+// f16-prec-std: -ffloat16-excess-precision=standard
+// RUN: %clang_cl /fexcess-precision=16 -### -- %s 2>&1 | FileCheck -check-prefix=f16-prec-none %s
+// f16-prec-none: -ffloat16-excess-precision=none
+
 // /source-charset: should warn on everything except UTF-8.
 // RUN: %clang_cl /source-charset:utf-16 -### -- %s 2>&1 | FileCheck -check-prefix=source-charset-utf-16 %s
 // source-charset-utf-16: invalid value 'utf-16' in '/source-charset:utf-16'