merge revision(s) 511b55bcefc81c036294dc9a544d14bd342acd3b: [Backport #17215]

	Enable arm64 optimizations that exist for power/x86 (#3393)

	* Enable unaligned accesses on arm64

	64-bit Arm platforms support unaligned accesses.

	Running the string benchmarks this change improves performance
	by an average of 1.04x, min .96x, max 1.21x, median 1.01x

	* arm64 enable gc optimizations

	Similar to x86 and powerpc optimizations.

	|       |compare-ruby|built-ruby|
	|:------|-----------:|---------:|
	|hash1  |       0.225|     0.237|
	|       |           -|     1.05x|
	|hash2  |       0.110|     0.110|
	|       |       1.00x|         -|

	* vm_exec.c: improve performance for arm64

	|                               |compare-ruby|built-ruby|
	|:------------------------------|-----------:|---------:|
	|vm_array                       |     26.501M|   27.959M|
	|                               |           -|     1.06x|
	|vm_attr_ivar                   |     21.606M|   31.429M|
	|                               |           -|     1.45x|
	|vm_attr_ivar_set               |     21.178M|   26.113M|
	|                               |           -|     1.23x|
	|vm_backtrace                   |       6.621|     6.668|
	|                               |           -|     1.01x|
	|vm_bigarray                    |     26.205M|   29.958M|
	|                               |           -|     1.14x|
	|vm_bighash                     |    504.155k|  479.306k|
	|                               |       1.05x|         -|
	|vm_block                       |     16.692M|   21.315M|
	|                               |           -|     1.28x|
	|block_handler_type_iseq        |       5.083|     7.004|
	|                               |           -|     1.38x|
	---
	 gc.c                           | 13 +++++++++++++
	 gc.h                           |  2 ++
	 include/ruby/internal/config.h |  2 ++
	 regint.h                       |  2 +-
	 siphash.c                      |  2 +-
	 st.c                           |  2 +-
	 vm_exec.c                      |  8 ++++++++
	 7 files changed, 28 insertions(+), 3 deletions(-)

8 files changed, 28 insertions, 4 deletions

diff --git a/gc.c b/gc.c
index 73faf46b12..b06fdc5b27 100644
--- a/gc.c
+++ b/gc.c
@@ -1153,6 +1153,19 @@ tick(void)
     return val;
 }
 
+#elif defined(__aarch64__) &&  defined(__GNUC__)
+typedef unsigned long tick_t;
+#define PRItick "lu"
+
+static __inline__ tick_t
+tick(void)
+{
+    unsigned long val;
+    __asm__ __volatile__ ("mrs %0, cntvct_el0", : "=r" (val));
+    return val;
+}
+
+
 #elif defined(_WIN32) && defined(_MSC_VER)
 #include <intrin.h>
 typedef unsigned __int64 tick_t;
diff --git a/gc.h b/gc.h
index cf794fa514..72e3935799 100644
--- a/gc.h
+++ b/gc.h
@@ -8,6 +8,8 @@
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("movl\t%%esp, %0" : "=r" (*(p)))
 #elif defined(__powerpc64__) && defined(__GNUC__)
 #define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("mr\t%0, %%r1" : "=r" (*(p)))
+#elif defined(__aarch64__) && defined(__GNUC__)
+#define SET_MACHINE_STACK_END(p) __asm__ __volatile__ ("mov\t%0, sp" : "=r" (*(p)))
 #else
 NOINLINE(void rb_gc_set_stack_end(VALUE **stack_end_p));
 #define SET_MACHINE_STACK_END(p) rb_gc_set_stack_end(p)
diff --git a/include/ruby/defines.h b/include/ruby/defines.h
index 5e03d49985..dc71d65100 100644
--- a/include/ruby/defines.h
+++ b/include/ruby/defines.h
@@ -486,6 +486,7 @@ void rb_sparc_flush_register_windows(void);
 # if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
      defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64) || \
      defined(__powerpc64__) || \
+     defined(__aarch64__) || \
      defined(__mc68020__)
 #   define UNALIGNED_WORD_ACCESS 1
 # else
diff --git a/regint.h b/regint.h
index a2f5bbba1d..0740429688 100644
--- a/regint.h
+++ b/regint.h
@@ -52,7 +52,7 @@
 #ifndef UNALIGNED_WORD_ACCESS
 # if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
      defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64) || \
-     defined(__powerpc64__) || \
+     defined(__powerpc64__) || defined(__aarch64__) || \
      defined(__mc68020__)
 #  define UNALIGNED_WORD_ACCESS 1
 # else
diff --git a/siphash.c b/siphash.c
index 153d2c690a..ddf8ee245d 100644
--- a/siphash.c
+++ b/siphash.c
@@ -30,7 +30,7 @@
 #ifndef UNALIGNED_WORD_ACCESS
 # if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
      defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64) || \
-     defined(__powerpc64__) || \
+     defined(__powerpc64__) || defined(__aarch64__) || \
      defined(__mc68020__)
 #   define UNALIGNED_WORD_ACCESS 1
 # endif
diff --git a/st.c b/st.c
index 2b973ea75d..4258f93ffc 100644
--- a/st.c
+++ b/st.c
@@ -1815,7 +1815,7 @@ st_values_check(st_table *tab, st_data_t *values, st_index_t size,
 #ifndef UNALIGNED_WORD_ACCESS
 # if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
      defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64) || \
-     defined(__powerpc64__) || \
+     defined(__powerpc64__) || defined(__aarch64__) || \
      defined(__mc68020__)
 #   define UNALIGNED_WORD_ACCESS 1
 # endif
diff --git a/version.h b/version.h
index f83a6fe673..b5c6533881 100644
--- a/version.h
+++ b/version.h
@@ -2,7 +2,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 3
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 167
+#define RUBY_PATCHLEVEL 168
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 3
diff --git a/vm_exec.c b/vm_exec.c
index 0adaa7b721..cb09738247 100644
--- a/vm_exec.c
+++ b/vm_exec.c
@@ -27,6 +27,9 @@ static void vm_analysis_insn(int insn);
 #elif defined(__GNUC__) && defined(__powerpc64__)
 #define DECL_SC_REG(type, r, reg) register type reg_##r __asm__("r" reg)
 
+#elif defined(__GNUC__) && defined(__aarch64__)
+#define DECL_SC_REG(type, r, reg) register type reg_##r __asm__("x" reg)
+
 #else
 #define DECL_SC_REG(type, r, reg) register type reg_##r
 #endif
@@ -74,6 +77,11 @@ vm_exec_core(rb_execution_context_t *ec, VALUE initial)
     DECL_SC_REG(rb_control_frame_t *, cfp, "15");
 #define USE_MACHINE_REGS 1
 
+#elif defined(__GNUC__) && defined(__aarch64__)
+    DECL_SC_REG(const VALUE *, pc, "19");
+    DECL_SC_REG(rb_control_frame_t *, cfp, "20");
+#define USE_MACHINE_REGS 1
+
 #else
     register rb_control_frame_t *reg_cfp;
     const VALUE *reg_pc;