aarch64: Add support for Armv8.8-A

This patch adds skeleton support for -march=armv8.8-a, testing only
that it correctly inherits from armv8.7-a.

include/
	* opcode/aarch64.h (AARCH64_FEATURE_V8_8): New macro.
	(AARCH64_ARCH_V8_8): Likewise.

gas/
	* doc/c-aarch64.texi: Document armv8.8-a.
	* config/tc-aarch64.c (aarch64_archs): Add armv8-8-a
	* testsuite/gas/aarch64/v8-8-a.s,
	* testsuite/gas/aarch64/v8-8-a.d: New test.

gas/config/tc-aarch64.c

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 497c126..2181fa1 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -9820,6 +9820,7 @@
   {"armv8.5-a", AARCH64_ARCH_V8_5},
   {"armv8.6-a", AARCH64_ARCH_V8_6},
   {"armv8.7-a", AARCH64_ARCH_V8_7},
+  {"armv8.8-a", AARCH64_ARCH_V8_8},
   {"armv8-r",	AARCH64_ARCH_V8_R},
   {"armv9-a",	AARCH64_ARCH_V9},
   {NULL, AARCH64_ARCH_NONE}

gas/doc/c-aarch64.texi

diff --git a/gas/doc/c-aarch64.texi b/gas/doc/c-aarch64.texi
index 6c39963..3051b6f 100644
--- a/gas/doc/c-aarch64.texi
+++ b/gas/doc/c-aarch64.texi
@@ -110,8 +110,8 @@
 instruction which will not execute on the target architecture.  The
 following architecture names are recognized: @code{armv8-a},
 @code{armv8.1-a}, @code{armv8.2-a}, @code{armv8.3-a}, @code{armv8.4-a}
-@code{armv8.5-a}, @code{armv8.6-a}, @code{armv8.7-a}, @code{armv8-r}, and
-@code{armv9-a}.
+@code{armv8.5-a}, @code{armv8.6-a}, @code{armv8.7-a}, @code{armv8.8-a},
+@code{armv8-r}, and @code{armv9-a}.
 
 If both @option{-mcpu} and @option{-march} are specified, the
 assembler will use the setting for @option{-mcpu}.  If neither are

gas/testsuite/gas/aarch64/v8-8-a.d

diff --git a/gas/testsuite/gas/aarch64/v8-8-a.d b/gas/testsuite/gas/aarch64/v8-8-a.d
new file mode 100644
index 0000000..50fb822
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/v8-8-a.d
@@ -0,0 +1,2 @@
+# objdump: -dr
+#...

gas/testsuite/gas/aarch64/v8-8-a.s

diff --git a/gas/testsuite/gas/aarch64/v8-8-a.s b/gas/testsuite/gas/aarch64/v8-8-a.s
new file mode 100644
index 0000000..f2568ef
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/v8-8-a.s
@@ -0,0 +1,5 @@
+	.arch armv8.8-a
+
+	ld64b x0, [x1]
+	dsb oshnxs
+	msr hcrx_el2, x0

include/opcode/aarch64.h

diff --git a/include/opcode/aarch64.h b/include/opcode/aarch64.h
index fa79aa9..493b797 100644
--- a/include/opcode/aarch64.h
+++ b/include/opcode/aarch64.h
@@ -94,6 +94,7 @@
 #define AARCH64_FEATURE_V9	     (1ULL << 56) /* Armv9.0-A processors.  */
 #define AARCH64_FEATURE_SME_F64	     (1ULL << 57) /* SME F64.  */
 #define AARCH64_FEATURE_SME_I64	     (1ULL << 58) /* SME I64.  */
+#define AARCH64_FEATURE_V8_8	     (1ULL << 59) /* Armv8.8 processors.  */
 
 /* Crypto instructions are the combination of AES and SHA2.  */
 #define AARCH64_FEATURE_CRYPTO	(AARCH64_FEATURE_SHA2 | AARCH64_FEATURE_AES)
@@ -141,6 +142,8 @@
 #define AARCH64_ARCH_V8_7	AARCH64_FEATURE (AARCH64_ARCH_V8_6,	\
 						 AARCH64_FEATURE_V8_7	\
 						 | AARCH64_FEATURE_LS64)
+#define AARCH64_ARCH_V8_8	AARCH64_FEATURE (AARCH64_ARCH_V8_7,	\
+						 AARCH64_FEATURE_V8_8)
 #define AARCH64_ARCH_V8_R	(AARCH64_FEATURE (AARCH64_ARCH_V8_4,	\
 						 AARCH64_FEATURE_V8_R)	\
 			      & ~(AARCH64_FEATURE_V8_A | AARCH64_FEATURE_LOR))