diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -6559,7 +6559,7 @@
 def _SLASH_external_env : CLJoined<"external:env:">,
   HelpText<"Add dirs in env var <var> to include search path with warnings suppressed">,
   MetaVarName<"<var>">;
-def _SLASH_FA : CLFlag<"FA">,
+def _SLASH_FA : CLJoined<"FA">,
   HelpText<"Output assembly code file during compilation">;
 def _SLASH_Fa : CLJoined<"Fa">,
   HelpText<"Set assembly output file name (with /FA)">,
@@ -6727,7 +6727,6 @@
 def _SLASH_experimental : CLJoined<"experimental:">;
 def _SLASH_exportHeader : CLFlag<"exportHeader">;
 def _SLASH_external : CLJoined<"external:">;
-def _SLASH_FA_joined : CLJoined<"FA">;
 def _SLASH_favor : CLJoined<"favor">;
 def _SLASH_fsanitize_address_use_after_return : CLJoined<"fsanitize-address-use-after-return">;
 def _SLASH_fno_sanitize_address_vcasan_lib : CLJoined<"fno-sanitize-address-vcasan-lib">;
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -65,20 +65,29 @@
 
 // RUN: %clang_cl -### /FA -fprofile-instr-generate -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-INSTR-GENERATE %s
 // RUN: %clang_cl -### /FA -fprofile-instr-generate=/tmp/somefile.profraw -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-INSTR-GENERATE-FILE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-instr-generate -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-INSTR-GENERATE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-instr-generate=/tmp/somefile.profraw -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-INSTR-GENERATE-FILE %s
 // CHECK-PROFILE-INSTR-GENERATE: "-fprofile-instrument=clang" "--dependent-lib=clang_rt.profile{{[^"]*}}.lib"
 // CHECK-PROFILE-INSTR-GENERATE-FILE: "-fprofile-instrument-path=/tmp/somefile.profraw"
 
 // RUN: %clang_cl -### /FA -fprofile-generate -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-GENERATE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-generate -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-GENERATE %s
 // CHECK-PROFILE-GENERATE: "-fprofile-instrument=llvm" "--dependent-lib=clang_rt.profile{{[^"]*}}.lib"
 
 // RUN: %clang_cl -### /FA -fprofile-instr-generate -fprofile-instr-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-GEN-USE %s
 // RUN: %clang_cl -### /FA -fprofile-instr-generate -fprofile-instr-use=file -- %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-GEN-USE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-instr-generate -fprofile-instr-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-GEN-USE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-instr-generate -fprofile-instr-use=file -- %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-GEN-USE %s
 // CHECK-NO-MIX-GEN-USE: '{{[a-z=-]*}}' not allowed with '{{[a-z=-]*}}'
 
 // RUN: %clang_cl -### /FA -fprofile-instr-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE %s
 // RUN: %clang_cl -### /FA -fprofile-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE %s
 // RUN: %clang_cl -### /FA -fprofile-instr-use=/tmp/somefile.prof -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE-FILE %s
 // RUN: %clang_cl -### /FA -fprofile-use=/tmp/somefile.prof -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE-FILE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-instr-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-instr-use=/tmp/somefile.prof -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE-FILE %s
+// RUN: %clang_cl -### /FAcsu -fprofile-use=/tmp/somefile.prof -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-USE-FILE %s
 // CHECK-PROFILE-USE: "-fprofile-instrument-use-path=default.profdata"
 // CHECK-PROFILE-USE-FILE: "-fprofile-instrument-use-path=/tmp/somefile.prof"
 
diff --git a/clang/test/Driver/cl-outputs.c b/clang/test/Driver/cl-outputs.c
--- a/clang/test/Driver/cl-outputs.c
+++ b/clang/test/Driver/cl-outputs.c
@@ -238,6 +238,28 @@
 // FaMULTIPLESOURCEOK: "-o" "cl-outputs.asm"
 // FaMULTIPLESOURCEOK: "-o" "cl-outputs.asm"
 
+// Copy of the same tests above, but with /FAcsu
+// RUN: %clang_cl /FAcsu -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU %s
+// FA_CSU: "-o" "cl-outputs.asm"
+// RUN: %clang_cl /FAcsu /Fa -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaEMPTY %s
+// FA_CSU_FaEMPTY: "-o" "cl-outputs.asm"
+// RUN: %clang_cl /FAcsu /Fafoo -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaNAME %s
+// RUN: %clang_cl /Fafoo -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaNAME %s
+// FA_CSU_FaNAME:  "-o" "foo.asm"
+// RUN: %clang_cl /FAcsu /Faa.ext /Fab.ext -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaNAMEEXT %s
+// FA_CSU_FaNAMEEXT:  "-o" "b.ext"
+// RUN: %clang_cl /FAcsu /Fafoo.dir/ -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaDIR %s
+// FA_CSU_FaDIR:  "-o" "foo.dir{{[/\\]+}}cl-outputs.asm"
+// RUN: %clang_cl /FAcsu /Fafoo.dir/a -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaDIRNAME %s
+// FA_CSU_FaDIRNAME:  "-o" "foo.dir{{[/\\]+}}a.asm"
+// RUN: %clang_cl /FAcsu /Fafoo.dir/a.ext -### -- %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaDIRNAMEEXT %s
+// FA_CSU_FaDIRNAMEEXT:  "-o" "foo.dir{{[/\\]+}}a.ext"
+// RUN: %clang_cl /Faa.asm -### -- %s %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaMULTIPLESOURCE %s
+// FA_CSU_FaMULTIPLESOURCE: error: cannot specify '/Faa.asm' when compiling multiple source files
+// RUN: %clang_cl /Fa -### -- %s %s 2>&1 | FileCheck -check-prefix=FA_CSU_FaMULTIPLESOURCEOK %s
+// FA_CSU_FaMULTIPLESOURCEOK: "-o" "cl-outputs.asm"
+// FA_CSU_FaMULTIPLESOURCEOK: "-o" "cl-outputs.asm"
+
 // RUN: %clang_cl /P -### -- %s 2>&1 | FileCheck -check-prefix=P %s
 // P: "-E"
 // P: "-o" "cl-outputs.i"