[llvm] MC: X86 intel syntax: Support data32 and data16 better (PR #156287)

[Danny Milosavljevic via llvm-commits]

================
@@ -0,0 +1,28 @@
+// RUN: llvm-mc -triple i386-unknown-unknown --x86-asm-syntax=intel --show-encoding %s | FileCheck %s
+
+// CHECK: encoding: [0x66,0x6a,0x08]
+          data16 push 8
----------------
daym wrote:

Does it?

```
$ cat boot.asm
.intel_syntax noprefix
.code32
	data16 push 8
$ as boot.asm
$ objdump -S a.out
$ objdump -S a.out 

a.out:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <test_section>:
   0:	66 6a 08             	pushw  $0x8
$ as --version
GNU assembler (GNU Binutils) 2.44
Copyright (C) 2025 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or later.
This program has absolutely no warranty.
This assembler was configured for a target of `x86_64-unknown-linux-gnu'.
```


https://github.com/llvm/llvm-project/pull/156287