[fixup] Bring internal instruction names into compliance with the naming convention

... and tweak a test a bit.

Author: momchil-velikov

llvm/lib/Target/AArch64/SMEInstrFormats.td

@@ -5361,14 +5361,14 @@ class sme2_bf16_fp16_quarter_tile_outer_product<bit M, bit N, bit S, string mnem
 
 multiclass sme2_bfmop4as_non_widening<bit S, string mnemonic> {
   // Single vectors
-  def _ZZ_H : sme2_bf16_fp16_quarter_tile_outer_product<0, 0, S, mnemonic, ZPR16Mul2_Lo, ZPR16Mul2_Hi>;
+  def _MZZ_H : sme2_bf16_fp16_quarter_tile_outer_product<0, 0, S, mnemonic, ZPR16Mul2_Lo, ZPR16Mul2_Hi>;
 
   // Multiple and single vectors
-  def _2ZZ_H : sme2_bf16_fp16_quarter_tile_outer_product<0, 1, S, mnemonic, ZZ_h_mul_r_Lo, ZPR16Mul2_Hi>;
+  def _M2ZZ_H : sme2_bf16_fp16_quarter_tile_outer_product<0, 1, S, mnemonic, ZZ_h_mul_r_Lo, ZPR16Mul2_Hi>;
 
   // Single and multiple vectors
-  def _Z2Z_H : sme2_bf16_fp16_quarter_tile_outer_product<1, 0, S, mnemonic, ZPR16Mul2_Lo, ZZ_h_mul_r_Hi>;
+  def _MZ2Z_H : sme2_bf16_fp16_quarter_tile_outer_product<1, 0, S, mnemonic, ZPR16Mul2_Lo, ZZ_h_mul_r_Hi>;
 
   // Multiple vectors
-  def _2Z2Z_H : sme2_bf16_fp16_quarter_tile_outer_product<1, 1, S, mnemonic, ZZ_h_mul_r_Lo, ZZ_h_mul_r_Hi>;
+  def _M2Z2Z_H : sme2_bf16_fp16_quarter_tile_outer_product<1, 1, S, mnemonic, ZZ_h_mul_r_Lo, ZZ_h_mul_r_Hi>;
 }

llvm/test/MC/AArch64/SME2p2/bfmop4as-non-widening.s

@@ -5,7 +5,7 @@
 // RUN: llvm-mc -triple=aarch64 -filetype=obj -mattr=+sme2p2,+sme-b16b16 < %s \
 // RUN:        | llvm-objdump -d --mattr=+sme2p2,+sme-b16b16 - | FileCheck %s --check-prefix=CHECK-INST
 // RUN: llvm-mc -triple=aarch64 -filetype=obj -mattr=+sme2p2,+sme-b16b16 < %s \
-// RUN:        | llvm-objdump -d --mattr=-sme2 - | FileCheck %s --check-prefix=CHECK-UNKNOWN
+// RUN:        | llvm-objdump -d --mattr=-sme2p2 - | FileCheck %s --check-prefix=CHECK-UNKNOWN
 // Disassemble encoding and check the re-encoding (-show-encoding) matches.
 // RUN: llvm-mc -triple=aarch64 -show-encoding -mattr=+sme2p2,+sme-b16b16 < %s \
 // RUN:        | sed '/.text/d' | sed 's/.*encoding: //g' \