feat(lint): accept the wired extension mnemonics

Assisted-by: GLM 5.3 Flash

lint/lint.go

@@ -328,15 +328,23 @@ func lintText(t *ast.Text, tab *arch.Table, archKnown bool, cfg Config, macros m
 			}
 
 			if archKnown && !cfg.Disable[CodeUnknownInstr] && !pseudoOps[upper] && !isMacroInvocation(mnem, macros) {
+				// The extended-instruction layer is a mnemonic's second home:
+				// one registered there (arm64's SVE family today) is known,
+				// and it encodes through the extension registry rather than
+				// the encoder mirror the unencodable rule consults, so the
+				// wired extensions are never flagged as a gap of the table.
+				_, extended := asm.LookupExtension(cfg.Arch, mnem)
 				if _, ok := tab.Lookup(mnem); !ok {
-					out = append(out, Diagnostic{
-						Pos:      st.Mnemonic.Pos,
-						End:      st.Mnemonic.End,
-						Severity: Error,
-						Code:     CodeUnknownInstr,
-						Message:  fmt.Sprintf("unknown %s instruction %q", cfg.Arch, mnem),
-					})
-				} else if cfg.Arch == arch.AMD64 && !cfg.Disable[CodeUnencodable] && !asm.Encodable(upper) {
+					if !extended {
+						out = append(out, Diagnostic{
+							Pos:      st.Mnemonic.Pos,
+							End:      st.Mnemonic.End,
+							Severity: Error,
+							Code:     CodeUnknownInstr,
+							Message:  fmt.Sprintf("unknown %s instruction %q", cfg.Arch, mnem),
+						})
+					}
+				} else if cfg.Arch == arch.AMD64 && !extended && !cfg.Disable[CodeUnencodable] && !asm.Encodable(upper) {
 					// Known to the architecture table but missing from the
 					// encoder: the file parses everywhere and then fails at
 					// assembly time.  Flag it at lint so the gap is visible