[gcc r13-3129] aarch64: Add test for LDAR generation from __atomic_load_n

[Kyrylo Tkachov <ktkachov@gcc.gnu.org>]

https://gcc.gnu.org/g:badd1ac23d24664b2258b1db4d49f37a3f60ccca

commit r13-3129-gbadd1ac23d24664b2258b1db4d49f37a3f60ccca
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date:   Thu Oct 6 12:08:40 2022 +0100

    aarch64: Add test for LDAR generation from __atomic_load_n
    
    I'd like a test to check the generation of LDAR for atomic_load_n.
    No new functionality added.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/aarch64/ldar_1.c: New test.

Diff:
---
 gcc/testsuite/gcc.target/aarch64/ldar_1.c | 66 +++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/gcc/testsuite/gcc.target/aarch64/ldar_1.c b/gcc/testsuite/gcc.target/aarch64/ldar_1.c
new file mode 100644
index 00000000000..d968a72b30f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/ldar_1.c
@@ -0,0 +1,66 @@
+/* Test the LDAR instruction generation from atomic acquire loads.  */
+/* { dg-do assemble } */
+/* { dg-additional-options "--save-temps -O1" } */
+/* { dg-final { check-function-bodies "**" "" "" } } */
+
+#include <stdint.h>
+
+#pragma GCC target "+norcpc"
+
+uint8_t v_uint8_t;
+uint16_t v_uint16_t;
+uint32_t v_uint32_t;
+uint64_t v_uint64_t;
+
+/*
+** load_uint8_t:
+**      ...
+**      ldarb	w0, \[x[0-9]+\]
+**      ret
+*/
+
+uint8_t
+load_uint8_t (void)
+{
+  return __atomic_load_n (&v_uint8_t, __ATOMIC_ACQUIRE);
+}
+
+/*
+** load_uint16_t:
+**      ...
+**      ldarh	w0, \[x[0-9]+\]
+**      ret
+*/
+
+uint16_t
+load_uint16_t (void)
+{
+  return __atomic_load_n (&v_uint16_t, __ATOMIC_ACQUIRE);
+}
+
+/*
+** load_uint32_t:
+**      ...
+**      ldar	w0, \[x[0-9]+\]
+**      ret
+*/
+
+uint32_t
+load_uint32_t (void)
+{
+  return __atomic_load_n (&v_uint32_t, __ATOMIC_ACQUIRE);
+}
+
+/*
+** load_uint64_t:
+**      ...
+**      ldar	x0, \[x[0-9]+\]
+**      ret
+*/
+
+uint64_t
+load_uint64_t (void)
+{
+  return __atomic_load_n (&v_uint64_t, __ATOMIC_ACQUIRE);
+}
+