Index: docs/ClangCommandLineReference.rst
===================================================================
--- docs/ClangCommandLineReference.rst
+++ docs/ClangCommandLineReference.rst
@@ -2334,6 +2334,42 @@
 
 Reserve the x20 register (AArch64 only)
 
+.. option:: -fcall-saved-x8
+
+Make the x8 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x9
+
+Make the x9 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x10
+
+Make the x10 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x11
+
+Make the x11 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x12
+
+Make the x12 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x13
+
+Make the x13 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x14
+
+Make the x14 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x15
+
+Make the x15 register call-saved (AArch64 only)
+
+.. option:: -fcall-saved-x18
+
+Make the x18 register call-saved (AArch64 only)
+
 .. option:: -mfix-cortex-a53-835769, -mno-fix-cortex-a53-835769
 
 Workaround Cortex-A53 erratum 835769 (AArch64 only)
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -2054,6 +2054,10 @@
   def ffixed_x#i : Flag<["-"], "ffixed-x"#i>, Group<m_aarch64_Features_Group>,
     HelpText<"Reserve the "#i#" register (AArch64 only)">;
 
+foreach i = {8-15,18} in
+  def fcall_saved_x#i : Flag<["-"], "fcall-saved-x"#i>, Group<m_aarch64_Features_Group>,
+    HelpText<"Make the x"#i#" register call-saved (AArch64 only)">;
+
 def msign_return_address : Joined<["-"], "msign-return-address=">,
   Flags<[CC1Option]>, Group<m_Group>,
   HelpText<"Select return address signing scope">, Values<"none,all,non-leaf">;
Index: lib/Driver/ToolChains/Arch/AArch64.cpp
===================================================================
--- lib/Driver/ToolChains/Arch/AArch64.cpp
+++ lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -251,6 +251,33 @@
   if (Args.hasArg(options::OPT_ffixed_x20))
     Features.push_back("+reserve-x20");
 
+  if (Args.hasArg(options::OPT_fcall_saved_x8))
+    Features.push_back("+call-saved-x8");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x9))
+    Features.push_back("+call-saved-x9");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x10))
+    Features.push_back("+call-saved-x10");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x11))
+    Features.push_back("+call-saved-x11");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x12))
+    Features.push_back("+call-saved-x12");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x13))
+    Features.push_back("+call-saved-x13");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x14))
+    Features.push_back("+call-saved-x14");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x15))
+    Features.push_back("+call-saved-x15");
+
+  if (Args.hasArg(options::OPT_fcall_saved_x18))
+    Features.push_back("+call-saved-x18");
+
   if (Args.hasArg(options::OPT_mno_neg_immediates))
     Features.push_back("+no-neg-immediates");
 }
Index: test/Driver/aarch64-call-saved-x-register.c
===================================================================
--- test/Driver/aarch64-call-saved-x-register.c
+++ test/Driver/aarch64-call-saved-x-register.c
@@ -0,0 +1,58 @@
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x8 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X8 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x9 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X9 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x10 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X10 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x11 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X11 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x12 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X12 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x13 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X13 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x14 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X14 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x15 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X15 %s
+
+// RUN: %clang -target aarch64-none-gnu -fcall-saved-x18 -### %s  2>&1  \
+// RUN: | FileCheck --check-prefix=CHECK-CALL-SAVED-X18 %s
+
+// Test all call-saved-x# options together.
+// RUN: %clang -target aarch64-none-gnu \
+// RUN: -fcall-saved-x8 \
+// RUN: -fcall-saved-x9 \
+// RUN: -fcall-saved-x10 \
+// RUN: -fcall-saved-x11 \
+// RUN: -fcall-saved-x12 \
+// RUN: -fcall-saved-x13 \
+// RUN: -fcall-saved-x14 \
+// RUN: -fcall-saved-x15 \
+// RUN: -fcall-saved-x18 \
+// RUN: -### %s  2>&1 | FileCheck %s \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X8 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X9 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X10 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X11 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X12 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X13 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X14 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X15 \
+// RUN: --check-prefix=CHECK-CALL-SAVED-X18
+
+// CHECK-CALL-SAVED-X8: "-target-feature" "+call-saved-x8"
+// CHECK-CALL-SAVED-X9: "-target-feature" "+call-saved-x9"
+// CHECK-CALL-SAVED-X10: "-target-feature" "+call-saved-x10"
+// CHECK-CALL-SAVED-X11: "-target-feature" "+call-saved-x11"
+// CHECK-CALL-SAVED-X12: "-target-feature" "+call-saved-x12"
+// CHECK-CALL-SAVED-X13: "-target-feature" "+call-saved-x13"
+// CHECK-CALL-SAVED-X14: "-target-feature" "+call-saved-x14"
+// CHECK-CALL-SAVED-X15: "-target-feature" "+call-saved-x15"
+// CHECK-CALL-SAVED-X18: "-target-feature" "+call-saved-x18"
Index: test/Driver/aarch64-fixed-call-saved-x-register.c
===================================================================
--- test/Driver/aarch64-fixed-call-saved-x-register.c
+++ test/Driver/aarch64-fixed-call-saved-x-register.c
@@ -0,0 +1,8 @@
+// Check that -ffixed and -fcall-saved flags work correctly together.
+// RUN: %clang -target aarch64-none-gnu \
+// RUN: -ffixed-x18 \
+// RUN: -fcall-saved-x18 \
+// RUN: -### %s  2>&1 | FileCheck %s
+
+// CHECK: "-target-feature" "+reserve-x18"
+// CHECK: "-target-feature" "+call-saved-x18"