* config/aarch64/aarch64.opt (-moutline-atomics): New.
        * config/aarch64/aarch64.c (aarch64_atomic_ool_func): New.
        (aarch64_ool_cas_names, aarch64_ool_swp_names): New.
        (aarch64_ool_ldadd_names, aarch64_ool_ldset_names): New.
        (aarch64_ool_ldclr_names, aarch64_ool_ldeor_names): New.
        (aarch64_expand_compare_and_swap): Honor TARGET_OUTLINE_ATOMICS.
        * config/aarch64/atomics.md (atomic_exchange<ALLI>): Likewise.
        (atomic_<atomic_op><ALLI>): Likewise.
        (atomic_fetch_<atomic_op><ALLI>): Likewise.
        (atomic_<atomic_op>_fetch<ALLI>): Likewise.
testsuite/
        * gcc.target/aarch64/atomic-op-acq_rel.c: Use -mno-outline-atomics.
        * gcc.target/aarch64/atomic-comp-swap-release-acquire.c: Likewise.
        * gcc.target/aarch64/atomic-op-acquire.c: Likewise.
        * gcc.target/aarch64/atomic-op-char.c: Likewise.
        * gcc.target/aarch64/atomic-op-consume.c: Likewise.
        * gcc.target/aarch64/atomic-op-imm.c: Likewise.
        * gcc.target/aarch64/atomic-op-int.c: Likewise.
        * gcc.target/aarch64/atomic-op-long.c: Likewise.
        * gcc.target/aarch64/atomic-op-relaxed.c: Likewise.
        * gcc.target/aarch64/atomic-op-release.c: Likewise.
        * gcc.target/aarch64/atomic-op-seq_cst.c: Likewise.
        * gcc.target/aarch64/atomic-op-short.c: Likewise.
        * gcc.target/aarch64/atomic_cmp_exchange_zero_reg_1.c: Likewise.
        * gcc.target/aarch64/atomic_cmp_exchange_zero_strong_1.c: Likewise.
        * gcc.target/aarch64/sync-comp-swap.c: Likewise.
        * gcc.target/aarch64/sync-op-acquire.c: Likewise.
        * gcc.target/aarch64/sync-op-full.c: Likewise.
---
 gcc/config/aarch64/aarch64-protos.h           | 13 +++
 gcc/config/aarch64/aarch64.c                  | 87 +++++++++++++++++
 .../atomic-comp-swap-release-acquire.c        |  2 +-
 .../gcc.target/aarch64/atomic-op-acq_rel.c    |  2 +-
 .../gcc.target/aarch64/atomic-op-acquire.c    |  2 +-
 .../gcc.target/aarch64/atomic-op-char.c       |  2 +-
 .../gcc.target/aarch64/atomic-op-consume.c    |  2 +-
 .../gcc.target/aarch64/atomic-op-imm.c        |  2 +-
 .../gcc.target/aarch64/atomic-op-int.c        |  2 +-
 .../gcc.target/aarch64/atomic-op-long.c       |  2 +-
 .../gcc.target/aarch64/atomic-op-relaxed.c    |  2 +-
 .../gcc.target/aarch64/atomic-op-release.c    |  2 +-
 .../gcc.target/aarch64/atomic-op-seq_cst.c    |  2 +-
 .../gcc.target/aarch64/atomic-op-short.c      |  2 +-
 .../aarch64/atomic_cmp_exchange_zero_reg_1.c  |  2 +-
 .../atomic_cmp_exchange_zero_strong_1.c       |  2 +-
 .../gcc.target/aarch64/sync-comp-swap.c       |  2 +-
 .../gcc.target/aarch64/sync-op-acquire.c      |  2 +-
 .../gcc.target/aarch64/sync-op-full.c         |  2 +-
 gcc/config/aarch64/aarch64.opt                |  3 +
 gcc/config/aarch64/atomics.md                 | 94 +++++++++++++++++--
 gcc/doc/invoke.texi                           | 16 +++-
 22 files changed, 221 insertions(+), 26 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-protos.h 
b/gcc/config/aarch64/aarch64-protos.h
index c4b73d26df6..1c1aac7201a 100644
--- a/gcc/config/aarch64/aarch64-protos.h
+++ b/gcc/config/aarch64/aarch64-protos.h
@@ -696,4 +696,17 @@ poly_uint64 aarch64_regmode_natural_size (machine_mode);
 
 bool aarch64_high_bits_all_ones_p (HOST_WIDE_INT);
 
+struct atomic_ool_names
+{
+    const char *str[5][4];
+};
+
+rtx aarch64_atomic_ool_func(machine_mode mode, rtx model_rtx,
+                           const atomic_ool_names *names);
+extern const atomic_ool_names aarch64_ool_swp_names;
+extern const atomic_ool_names aarch64_ool_ldadd_names;
+extern const atomic_ool_names aarch64_ool_ldset_names;
+extern const atomic_ool_names aarch64_ool_ldclr_names;
+extern const atomic_ool_names aarch64_ool_ldeor_names;
+
 #endif /* GCC_AARCH64_PROTOS_H */
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index b937514e6f8..56a4a47db73 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -16867,6 +16867,82 @@ aarch64_emit_unlikely_jump (rtx insn)
   add_reg_br_prob_note (jump, profile_probability::very_unlikely ());
 }
 
+/* We store the names of the various atomic helpers in a 5x4 array.
+   Return the libcall function given MODE, MODEL and NAMES.  */
+
+rtx
+aarch64_atomic_ool_func(machine_mode mode, rtx model_rtx,
+                       const atomic_ool_names *names)
+{
+  memmodel model = memmodel_base (INTVAL (model_rtx));
+  int mode_idx, model_idx;
+
+  switch (mode)
+    {
+    case E_QImode:
+      mode_idx = 0;
+      break;
+    case E_HImode:
+      mode_idx = 1;
+      break;
+    case E_SImode:
+      mode_idx = 2;
+      break;
+    case E_DImode:
+      mode_idx = 3;
+      break;
+    case E_TImode:
+      mode_idx = 4;
+      break;
+    default:
+      gcc_unreachable ();
+    }
+
+  switch (model)
+    {
+    case MEMMODEL_RELAXED:
+      model_idx = 0;
+      break;
+    case MEMMODEL_CONSUME:
+    case MEMMODEL_ACQUIRE:
+      model_idx = 1;
+      break;
+    case MEMMODEL_RELEASE:
+      model_idx = 2;
+      break;
+    case MEMMODEL_ACQ_REL:
+    case MEMMODEL_SEQ_CST:
+      model_idx = 3;
+      break;
+    default:
+      gcc_unreachable ();
+    }
+
+  return init_one_libfunc_visibility (names->str[mode_idx][model_idx],
+                                     VISIBILITY_HIDDEN);
+}
+
+#define DEF0(B, N) \
+  { "__aarch64_" #B #N "_relax", \
+    "__aarch64_" #B #N "_acq", \
+    "__aarch64_" #B #N "_rel", \
+    "__aarch64_" #B #N "_acq_rel" }
+
+#define DEF4(B)  DEF0(B, 1), DEF0(B, 2), DEF0(B, 4), DEF0(B, 8), \
+                { NULL, NULL, NULL, NULL }
+#define DEF5(B)  DEF0(B, 1), DEF0(B, 2), DEF0(B, 4), DEF0(B, 8), DEF0(B, 16)
+
+static const atomic_ool_names aarch64_ool_cas_names = { { DEF5(cas) } };
+const atomic_ool_names aarch64_ool_swp_names = { { DEF4(swp) } };
+const atomic_ool_names aarch64_ool_ldadd_names = { { DEF4(ldadd) } };
+const atomic_ool_names aarch64_ool_ldset_names = { { DEF4(ldset) } };
+const atomic_ool_names aarch64_ool_ldclr_names = { { DEF4(ldclr) } };
+const atomic_ool_names aarch64_ool_ldeor_names = { { DEF4(ldeor) } };
+
+#undef DEF0
+#undef DEF4
+#undef DEF5
+
 /* Expand a compare and swap pattern.  */
 
 void
@@ -16913,6 +16989,17 @@ aarch64_expand_compare_and_swap (rtx operands[])
                                                   newval, mod_s));
       cc_reg = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode);
     }
+  else if (TARGET_OUTLINE_ATOMICS)
+    {
+      /* Oldval must satisfy compare afterward.  */
+      if (!aarch64_plus_operand (oldval, mode))
+       oldval = force_reg (mode, oldval);
+      rtx func = aarch64_atomic_ool_func (mode, mod_s, &aarch64_ool_cas_names);
+      rval = emit_library_call_value (func, NULL_RTX, LCT_NORMAL, r_mode,
+                                     oldval, mode, newval, mode,
+                                     XEXP (mem, 0), Pmode);
+      cc_reg = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode);
+    }
   else
     {
       /* The oldval predicate varies by mode.  Test it and force to reg.  */
diff --git 
a/gcc/testsuite/gcc.target/aarch64/atomic-comp-swap-release-acquire.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-comp-swap-release-acquire.c
index 49ca5d0d09c..a828a72aa75 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-comp-swap-release-acquire.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-comp-swap-release-acquire.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2 -fno-ipa-icf" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -fno-ipa-icf -mno-outline-atomics" } 
*/
 
 #include "atomic-comp-swap-release-acquire.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-acq_rel.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-acq_rel.c
index 74f26348e42..6823ce381b2 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-acq_rel.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-acq_rel.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-acq_rel.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-acquire.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-acquire.c
index 66c1b1efe20..87937de378a 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-acquire.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-acquire.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-acquire.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-char.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-char.c
index c09d0434ecf..60955e57da3 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-char.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-char.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-char.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-consume.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-consume.c
index 5783ab84f5c..16cb11aeeaf 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-consume.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-consume.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-consume.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-imm.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-imm.c
index 18b8f0b04e9..bcab4e481e3 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-imm.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-imm.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 int v = 0;
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-int.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-int.c
index 8520f0839ba..040e4a8d168 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-int.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-int.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-int.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-long.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-long.c
index d011f8c5ce2..fc88b92cd3e 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-long.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-long.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 long v = 0;
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-relaxed.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-relaxed.c
index ed96bfdb978..503d62b0280 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-relaxed.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-relaxed.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-relaxed.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-release.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-release.c
index fc4be17de89..efe14aea7e4 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-release.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-release.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-release.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-seq_cst.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-seq_cst.c
index 613000fe490..09973bf82ba 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-seq_cst.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-seq_cst.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-seq_cst.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-op-short.c 
b/gcc/testsuite/gcc.target/aarch64/atomic-op-short.c
index e82c8118ece..e1dcebb0f89 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-op-short.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-op-short.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "atomic-op-short.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_reg_1.c 
b/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_reg_1.c
index f2a21ddf2e1..29246979bfb 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_reg_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_reg_1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -march=armv8-a+nolse" } */
+/* { dg-options "-O2 -march=armv8-a+nolse -mno-outline-atomics" } */
 /* { dg-skip-if "" { *-*-* } { "-mcpu=*" } { "" } } */
 
 int
diff --git 
a/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_strong_1.c 
b/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_strong_1.c
index 8d2ae67dfbe..6daf9b08f5a 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_strong_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic_cmp_exchange_zero_strong_1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -march=armv8-a+nolse" } */
+/* { dg-options "-O2 -march=armv8-a+nolse -mno-outline-atomics" } */
 /* { dg-skip-if "" { *-*-* } { "-mcpu=*" } { "" } } */
 
 int
diff --git a/gcc/testsuite/gcc.target/aarch64/sync-comp-swap.c 
b/gcc/testsuite/gcc.target/aarch64/sync-comp-swap.c
index e571b2f13b3..f56415f3354 100644
--- a/gcc/testsuite/gcc.target/aarch64/sync-comp-swap.c
+++ b/gcc/testsuite/gcc.target/aarch64/sync-comp-swap.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2 -fno-ipa-icf" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -fno-ipa-icf -mno-outline-atomics" } 
*/
 
 #include "sync-comp-swap.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sync-op-acquire.c 
b/gcc/testsuite/gcc.target/aarch64/sync-op-acquire.c
index 357bf1be3b2..39b3144aa36 100644
--- a/gcc/testsuite/gcc.target/aarch64/sync-op-acquire.c
+++ b/gcc/testsuite/gcc.target/aarch64/sync-op-acquire.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "sync-op-acquire.x"
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sync-op-full.c 
b/gcc/testsuite/gcc.target/aarch64/sync-op-full.c
index c6ba1629965..6b8b2043f40 100644
--- a/gcc/testsuite/gcc.target/aarch64/sync-op-full.c
+++ b/gcc/testsuite/gcc.target/aarch64/sync-op-full.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=armv8-a+nolse -O2" } */
+/* { dg-options "-march=armv8-a+nolse -O2 -mno-outline-atomics" } */
 
 #include "sync-op-full.x"
 
diff --git a/gcc/config/aarch64/aarch64.opt b/gcc/config/aarch64/aarch64.opt
index 55d466068b8..865b6a6d8ca 100644
--- a/gcc/config/aarch64/aarch64.opt
+++ b/gcc/config/aarch64/aarch64.opt
@@ -255,3 +255,6 @@ user-land code.
 TargetVariable
 long aarch64_stack_protector_guard_offset = 0
 
+moutline-atomics
+Target Report Mask(OUTLINE_ATOMICS) Save
+Generate local calls to out-of-line atomic operations.
diff --git a/gcc/config/aarch64/atomics.md b/gcc/config/aarch64/atomics.md
index f8bdd048b37..2e59b868420 100644
--- a/gcc/config/aarch64/atomics.md
+++ b/gcc/config/aarch64/atomics.md
@@ -186,16 +186,27 @@
   (match_operand:SI 3 "const_int_operand")]
   ""
   {
-    rtx (*gen) (rtx, rtx, rtx, rtx);
-
     /* Use an atomic SWP when available.  */
     if (TARGET_LSE)
-      gen = gen_aarch64_atomic_exchange<mode>_lse;
+      {
+       emit_insn (gen_aarch64_atomic_exchange<mode>_lse
+                  (operands[0], operands[1], operands[2], operands[3]));
+      }
+    else if (TARGET_OUTLINE_ATOMICS)
+      {
+       machine_mode mode = <MODE>mode;
+       rtx func = aarch64_atomic_ool_func (mode, operands[3],
+                                           &aarch64_ool_swp_names);
+       rtx rval = emit_library_call_value (func, operands[0], LCT_NORMAL,
+                                           mode, operands[2], mode,
+                                           XEXP (operands[1], 0), Pmode);
+        emit_move_insn (operands[0], rval);
+      }
     else
-      gen = gen_aarch64_atomic_exchange<mode>;
-
-    emit_insn (gen (operands[0], operands[1], operands[2], operands[3]));
-
+      {
+       emit_insn (gen_aarch64_atomic_exchange<mode>
+                  (operands[0], operands[1], operands[2], operands[3]));
+      }
     DONE;
   }
 )
@@ -280,6 +291,39 @@
          }
        operands[1] = force_reg (<MODE>mode, operands[1]);
       }
+    else if (TARGET_OUTLINE_ATOMICS)
+      {
+        const atomic_ool_names *names;
+       switch (<CODE>)
+         {
+         case MINUS:
+           operands[1] = expand_simple_unop (<MODE>mode, NEG, operands[1],
+                                             NULL, 1);
+           /* fallthru */
+         case PLUS:
+           names = &aarch64_ool_ldadd_names;
+           break;
+         case IOR:
+           names = &aarch64_ool_ldset_names;
+           break;
+         case XOR:
+           names = &aarch64_ool_ldeor_names;
+           break;
+         case AND:
+           operands[1] = expand_simple_unop (<MODE>mode, NOT, operands[1],
+                                             NULL, 1);
+           names = &aarch64_ool_ldclr_names;
+           break;
+         default:
+           gcc_unreachable ();
+         }
+        machine_mode mode = <MODE>mode;
+       rtx func = aarch64_atomic_ool_func (mode, operands[2], names);
+       emit_library_call_value (func, NULL_RTX, LCT_NORMAL, mode,
+                                operands[1], mode,
+                                XEXP (operands[0], 0), Pmode);
+        DONE;
+      }
     else
       gen = gen_aarch64_atomic_<atomic_optab><mode>;
 
@@ -405,6 +449,40 @@
        }
       operands[2] = force_reg (<MODE>mode, operands[2]);
     }
+  else if (TARGET_OUTLINE_ATOMICS)
+    {
+      const atomic_ool_names *names;
+      switch (<CODE>)
+       {
+       case MINUS:
+         operands[2] = expand_simple_unop (<MODE>mode, NEG, operands[2],
+                                           NULL, 1);
+         /* fallthru */
+       case PLUS:
+         names = &aarch64_ool_ldadd_names;
+         break;
+       case IOR:
+         names = &aarch64_ool_ldset_names;
+         break;
+       case XOR:
+         names = &aarch64_ool_ldeor_names;
+         break;
+       case AND:
+         operands[2] = expand_simple_unop (<MODE>mode, NOT, operands[2],
+                                           NULL, 1);
+         names = &aarch64_ool_ldclr_names;
+         break;
+       default:
+         gcc_unreachable ();
+       }
+      machine_mode mode = <MODE>mode;
+      rtx func = aarch64_atomic_ool_func (mode, operands[3], names);
+      rtx rval = emit_library_call_value (func, operands[0], LCT_NORMAL, mode,
+                                         operands[2], mode,
+                                         XEXP (operands[1], 0), Pmode);
+      emit_move_insn (operands[0], rval);
+      DONE;
+    }
   else
     gen = gen_aarch64_atomic_fetch_<atomic_optab><mode>;
 
@@ -494,7 +572,7 @@
 {
   /* Use an atomic load-operate instruction when possible.  In this case
      we will re-compute the result from the original mem value. */
-  if (TARGET_LSE)
+  if (TARGET_LSE || TARGET_OUTLINE_ATOMICS)
     {
       rtx tmp = gen_reg_rtx (<MODE>mode);
       operands[2] = force_reg (<MODE>mode, operands[2]);
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 0e3693598e7..900fda1efb2 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -643,7 +643,8 @@ Objective-C and Objective-C++ Dialects}.
 -march=@var{name}  -mcpu=@var{name}  -mtune=@var{name}  @gol
 -moverride=@var{string}  -mverbose-cost-dump @gol
 -mstack-protector-guard=@var{guard} -mstack-protector-guard-reg=@var{sysreg} 
@gol
--mstack-protector-guard-offset=@var{offset} -mtrack-speculation }
+-mstack-protector-guard-offset=@var{offset} -mtrack-speculation @gol
+-moutline-atomics }
 
 @emph{Adapteva Epiphany Options}
 @gccoptlist{-mhalf-reg-file  -mprefer-short-insn-regs @gol
@@ -15874,6 +15875,19 @@ be used by the compiler when expanding calls to
 @code{__builtin_speculation_safe_copy} to permit a more efficient code
 sequence to be generated.
 
+@item -moutline-atomics
+@itemx -mno-outline-atomics
+Enable or disable calls to out-of-line helpers to implement atomic operations.
+These helpers will, at runtime, determine if ARMv8.1-Atomics instructions
+should be used; if not, they will use the load/store-exclusive instructions
+that are present in the base ARMv8.0 ISA.
+
+This option is only applicable when compiling for the base ARMv8.0
+instruction set.  If using a later revision, e.g. @option{-march=armv8.1-a}
+or @option{-march=armv8-a+lse}, the ARMv8.1-Atomics instructions will be
+used directly.  The same applies when using @option{-mcpu=} when the
+selected cpu supports the @samp{lse} feature.
+
 @item -march=@var{name}
 @opindex march
 Specify the name of the target architecture and, optionally, one or
-- 
2.17.1

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