On Wed, 17 Jul 2024, Jakub Jelinek wrote:
> Hi!
>
> Apparently there is a -Wsign-compare warning if ptrdiff_t has precision of
> int, then (t - s + 1 + 2) / 3 * 4 has int type while cnt unsigned int.
> This doesn't warn if ptrdiff_t has larger precision, say on x86_64
> it is 64-bit and so (t - s + 1 + 2) / 3 * 4 has long type and cnt unsigned
> int. And it doesn't warn when using older binutils (in my tests I've
> used new binutils on x86_64 and old binutils on i686).
> Anyway, earlier condition guarantees that t - s is at most 256-ish and
> t >= s by construction, so we can just cast it to (unsigned) to avoid
> the warning.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
> 2024-07-17 Jakub Jelinek <ja...@redhat.com>
>
> PR other/115958
> * varasm.cc (default_elf_asm_output_ascii): Cast t - s to unsigned
> to avoid -Wsign-compare warnings.
>
> --- gcc/varasm.cc.jj 2024-07-16 19:33:53.553501415 +0200
> +++ gcc/varasm.cc 2024-07-16 22:35:05.132495049 +0200
> @@ -8558,7 +8558,7 @@ default_elf_asm_output_ascii (FILE *f, c
> {
> if (t == p && t != s)
> {
> - if (cnt <= (t - s + 1 + 2) / 3 * 4
> + if (cnt <= ((unsigned) (t - s) + 1 + 2) / 3 * 4
> && (!prev_base64 || (t - s) >= 16)
> && ((t - s) > 1 || cnt <= 2))
> {
> @@ -8584,7 +8584,7 @@ default_elf_asm_output_ascii (FILE *f, c
> break;
> }
> }
> - if (cnt > (t - s + 2) / 3 * 4 && (t - s) >= 3)
> + if (cnt > ((unsigned) (t - s) + 2) / 3 * 4 && (t - s) >= 3)
> {
> if (bytes_in_chunk > 0)
> {
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
