RISC-V: Add SiFive cease extension v1.0

Add SiFive cease extension,
https://sifive.cdn.prismic.io/sifive/767804da-53b2-4893-97d5-b7c030ae0a94_s76mc_core_complex_manual_21G3.pdf

This aligns LLVM:
* https://llvm.org/docs/RISCVUsage.html
* https://github.com/llvm/llvm-project/pull/83896

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_supported_vendor_x_ext): Add support for
	'xsfcease'.
	(riscv_multi_subset_supports): Handle INSN_CLASS_XSFCEASE.
	(riscv_multi_subset_supports_ext): Handle INSN_CLASS_XSFCEASE.

gas/ChangeLog:

	* doc/c-riscv.texi: Updated.
	* testsuite/gas/riscv/march-help.l: Updated.
	* testsuite/gas/riscv/sifive-insns.d: Add test case for 'sf.cease'.
	* testsuite/gas/riscv/sifive-insns.s: Likewise.

include/ChangeLog:

	* opcode/riscv-opc.h (MATCH_SF_CEASE, MASK_SF_CEASE): Define match and
	mask encoding for 'sf.cease'.
	* opcode/riscv.h (INSN_CLASS_XSFCEASE): Add new instruction class for
	'xsfcease'.

opcodes/ChangeLog:

    * riscv-opc.c (riscv_opcodes): Add opcode entry for 'sf.cease'.

1 files changed, 6 insertions, 1 deletions

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 6dc7193..275b2ef 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1485,7 +1485,8 @@ static struct riscv_supported_ext riscv_supported_vendor_x_ext[] =
   {"xtheadvector",	ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
   {"xtheadzvamo",	ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
   {"xventanacondops",	ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
-  {"xsfvcp",		ISA_SPEC_CLASS_DRAFT,	1, 0, 0},
+  {"xsfvcp",		ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
+  {"xsfcease",		ISA_SPEC_CLASS_DRAFT,	1, 0, 0 },
   {NULL, 0, 0, 0, 0}
 };
 
@@ -2736,6 +2737,8 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
       return riscv_subset_supports (rps, "xventanacondops");
     case INSN_CLASS_XSFVCP:
       return riscv_subset_supports (rps, "xsfvcp");
+    case INSN_CLASS_XSFCEASE:
+      return riscv_subset_supports (rps, "xsfcease");
     default:
       rps->error_handler
         (_("internal: unreachable INSN_CLASS_*"));
@@ -3004,6 +3007,8 @@ riscv_multi_subset_supports_ext (riscv_parse_subset_t *rps,
       return "xtheadvector";
     case INSN_CLASS_XTHEADZVAMO:
       return "xtheadzvamo";
+    case INSN_CLASS_XSFCEASE:
+      return "xsfcease";
     default:
       rps->error_handler
         (_("internal: unreachable INSN_CLASS_*"));