fix(asm): enforce the arm64 TLBI, RPRFM, FCVT and integer-pair arities

Assisted-by: GLM 5.3

asm/arm64_errorparity_test.go

@@ -15,28 +15,15 @@ import (
 // arm64AcceptedErrorShapes lists the toolchain's arm64error.s spellings gasm
 // still accepts, each an acceptance superset with a known shape.  The list
 // only shrinks: every tightening of the encoder moves spellings out of it,
-// and a spelling reappearing here means a regression.
-var arm64AcceptedErrorShapes = []string{
-	// spelling, the .P immediate against the aggregate register size, the
-	// REGTMP (R27) as an explicit operand the toolchain refuses, the pair
-	// split paths included.
-	// TLBI operand arity and the range-prefetch operand shapes.
-	"TLBI VMALLE1IS, R0",
-	"TLBI ALLE3OS, ZR",
-	"TLBI VAE1IS",
-	"TLBI RVALE3",
-	"RPRFM (R1), RSP, PLDKEEP",
-	// The GP register pairs on the FP mnemonics, the other way round.
-	"LDP (R0), (F0, F1)",
-	"STP (F2, F3), (R0)",
-	// FCVTL exists for the S to D pair alone.
-	"VFCVTL V1.H4, V2.S4",
-}
+// and a spelling reappearing here means a regression.  The catalogue is
+// empty as of Go 1.27: every line the toolchain's corpus rejects, gasm
+// rejects too.
+var arm64AcceptedErrorShapes = []string{}
 
 // TestArm64ToolchainErrorParity walks the toolchain's arm64error.s (Go
-// 1.27, arm64) and requires gasm to reject every case the toolchain rejects,
-// the documented acceptance supersets above excepted.  A live Go toolchain
-// is needed for the source file; the test skips without one or in -short.
+// 1.27, arm64) and requires gasm to reject every case the toolchain rejects.
+// A live Go toolchain is needed for the source file; the test skips without
+// one or in -short.
 func TestArm64ToolchainErrorParity(t *testing.T) {
 	if testing.Short() {
 		t.Skip("live arm64error.s corpus: skipped in -short mode")
@@ -65,12 +52,6 @@ func TestArm64ToolchainErrorParity(t *testing.T) {
 		}
 		body = strings.ReplaceAll(body, "\t", " ")
 		body = strings.Join(strings.Fields(body), " ")
-		// Label-relative and non-operand lines need their function context.
-		if strings.Contains(body, "(PC)") || strings.Contains(body, "(SB)") || strings.Contains(body, "PCALIGN") ||
-			strings.HasPrefix(body, "RET") || strings.HasPrefix(body, "NOP") || strings.HasPrefix(body, "BRK") ||
-			strings.Contains(body, "again") || strings.Contains(body, "next") || strings.Contains(body, "loop") {
-			continue
-		}
 		src := "#include \"textflag.h\"\n\nTEXT ·f(SB), NOSPLIT, $0-0\n\t" + body + "\n\tRET\n"
 		f, perr := parser.Parse("errorparity.s", src)
 		if len(perr) > 0 {