[PATCH 2/3] bpf: md: fix "*movsi" to generate wN regs [PR124688]

[Vineet Gupta]

On 3/29/26 4:17 PM, Vineet Gupta wrote:
> From: Vineet Gupta <gvineet@fb.com>
>
> movsi currently only generates DImode rN regs, despite RTL being SImode.
>
> | (insn 14 5 11 (set (reg:SI 1 %r1 [23])
> |        (reg:SI 0 %r0))  {*movsi}
> |     (expr_list:REG_DEAD (reg:SI 0 %r0)
> |        (nil)))
>
> generates
>
> |  r1 = r0
>
> as opposed to
>
> | w1 = w0
>
> This is not just issue of taste or getting more wN regs. As
> illustrated by test, this can be a correctness issue where mov
> needs to zero out the upper bits.
>
> Again the issue is asm teplmate of pattern missing 'w' specifier,
> leading bpf_print_register() to only generate 64-bit rN regs.
> Using 'w' allows either wN/rN reg depending on the mode.
>
> 	PR target/124688
>
> gcc/ChangeLog:
>
> 	* config/bpf/bpf.md (*movsi): Add 'w' to asm template.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/bpf/ret-reuse-arg-1.c: New test.
>
> Signed-off-by: Vineet Gupta <vineet.gupta@linux.dev>

Oh just realized that this needs assembler update. So need to post that 
first and also gate this change based on configure time detection of 
updated gas.

-Vineet