aarch64: Remove B16B16, SVE2p1 and SME2p1

Support for these extensions is broken and incomplete in the 2.42
branch, with a number of syntax and opcode bugs.  This patch removes the
flags and documentation, to avoid any further suggestion that this
extension is fully and correctly supported.

(cherry picked from commit d816fda3cbd83ff5c2700bf5f001d59fcaf75985)

6 files changed, 9 insertions, 16 deletions

diff --git a/gas/NEWS b/gas/NEWS
index 67d806cbf89..dfccd9f1dc7 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -1,15 +1,14 @@
 -*- text -*-
 
-Changes in 2.42:
-
-* Added support for AMD znver5 processor (available from GNU Binutils 2.42 release).
+Changes in 2.42.1:
 
-* Add support for the AArch64 Scalable Vector Extension version 2.1 (SVE2.1).
+* The options to enable the AArch64 SVE2.1, SME2.1 and B16B16 extensions have
+  been disabled, because of a number of known issues with their implementation
+  in the 2.42 release.
 
-* Add support for the AArch64 Scalable Matrix Extension version 2.1 (SME2.1).
+Changes in 2.42:
 
-* Add support for the AArch64 BFloat16 to BFloat16 arithmetic for SVE2 and SME2
-  (B16B16).
+* Added support for AMD znver5 processor (available from GNU Binutils 2.42 release).
 
 * Add support for the AArch64 Reliability, Availability and Serviceability
   extension v2 (RASv2).
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 0c6de289408..a7c29d2f03f 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -10425,9 +10425,6 @@ static const struct aarch64_option_cpu_value_table aarch64_features[] = {
   {"ite",		AARCH64_FEATURE (ITE), AARCH64_NO_FEATURES},
   {"d128",		AARCH64_FEATURE (D128),
 			AARCH64_FEATURE (LSE128)},
-  {"b16b16",		AARCH64_FEATURE (B16B16), AARCH64_FEATURE (SVE2)},
-  {"sme2p1",		AARCH64_FEATURE (SME2p1), AARCH64_FEATURE (SME2)},
-  {"sve2p1",		AARCH64_FEATURE (SVE2p1), AARCH64_FEATURE (SVE2)},
   {"rcpc3",		AARCH64_FEATURE (RCPC3), AARCH64_FEATURE (RCPC2)},
   {NULL,		AARCH64_NO_FEATURES, AARCH64_NO_FEATURES},
 };
diff --git a/gas/doc/c-aarch64.texi b/gas/doc/c-aarch64.texi
index 4f97768206c..77226a07973 100644
--- a/gas/doc/c-aarch64.texi
+++ b/gas/doc/c-aarch64.texi
@@ -161,8 +161,6 @@ automatically cause those extensions to be disabled.
 @headitem Extension @tab Depends upon @tab Description
 @item @code{aes} @tab @code{simd}
  @tab Enable the AES and PMULL cryptographic extensions.
-@item @code{b16b16} @tab @code{sve2}
- @tab Enable BFloat16 to BFloat16 arithmetic for SVE2 and SME2.
 @item @code{bf16} @tab @code{fp}
  @tab Enable BFloat16 extension.
 @item @code{chk} @tab
@@ -263,8 +261,6 @@ automatically cause those extensions to be disabled.
  @tab Enable SME I16I64 Extension.
 @item @code{sme2} @tab @code{sme}
  @tab Enable SME2.
-@item @code{sme2p1} @tab @code{sme2}
- @tab Enable SME2.1.
 @item @code{ssbs} @tab
  @tab Enable Speculative Store Bypassing Safe state read and write.
 @item @code{sve} @tab @code{fcma}
@@ -279,8 +275,6 @@ automatically cause those extensions to be disabled.
  @tab Enable the SVE2 SHA3 Extension.
 @item @code{sve2-sm4} @tab @code{sve2}, @code{sm4}
  @tab Enable the SVE2 SM4 Extension.
-@item @code{sve2p1} @tab @code{sve2}
- @tab Enable SVE2.1.
 @item @code{the} @tab
  @tab Enable the Translation Hardening Extension.
 @item @code{tme} @tab
diff --git a/gas/testsuite/gas/aarch64/bfloat16-1.d b/gas/testsuite/gas/aarch64/bfloat16-1.d
index f0d436bec58..0f4ab764d24 100644
--- a/gas/testsuite/gas/aarch64/bfloat16-1.d
+++ b/gas/testsuite/gas/aarch64/bfloat16-1.d
@@ -1,6 +1,7 @@
 #name: Test of SVE2.1 and SME2.1 non-widening BFloat16 instructions.
 #as: -march=armv9.4-a+b16b16
 #objdump: -dr
+#xfail: *-*-*
 
 [^:]+:     file format .*
 
diff --git a/gas/testsuite/gas/aarch64/sme2p1-1.d b/gas/testsuite/gas/aarch64/sme2p1-1.d
index a6e7b766402..4b94cc9e4a0 100644
--- a/gas/testsuite/gas/aarch64/sme2p1-1.d
+++ b/gas/testsuite/gas/aarch64/sme2p1-1.d
@@ -1,6 +1,7 @@
 #name: Test of SME2.1 movaz instructions.
 #as: -march=armv9.4-a+sme2p1
 #objdump: -dr
+#xfail: *-*-*
 
 [^:]+:     file format .*
 
diff --git a/gas/testsuite/gas/aarch64/sve2p1-1.d b/gas/testsuite/gas/aarch64/sve2p1-1.d
index daece899b38..72fac004141 100644
--- a/gas/testsuite/gas/aarch64/sve2p1-1.d
+++ b/gas/testsuite/gas/aarch64/sve2p1-1.d
@@ -1,6 +1,7 @@
 #name: Test of SVE2.1 min max instructions.
 #as: -march=armv9.4-a+sve2p1
 #objdump: -dr
+#xfail: *-*-*
 
 [^:]+:     file format .*