Re: [PATCH] Kill div64.h dupes, parenthesize do_div() macro params

From: Linus Torvalds (
Date: Wed Jul 02 2003 - 00:06:41 EST

On Wed, 2 Jul 2003, Bernardo Innocenti wrote:
> By the way, what do you think about getting rid of the do_div() macro
> altogether? I've noticed that gcc 3.3 is quite capable of guessing the
> optimal instruction pattern to use even for the generic do_div()
> written in C:

No thank you. 3.x is still broken enough that I don't want to force people
to use it.

> This code makes gcc select the "udivmodsi4" pattern on the m68k
> backend

Who cares about m68k? Does it do the right thing on x86? gcc 3.2.2 does
not, it does a "call __udivdi3" + "call __umoddi3", which is a 64/64->64
thing, which is totally inappropriate, and about a million times slower
than a single "udiv".

gcc is crap when it comes to long long. Always has been.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

This archive was generated by hypermail 2b29 : Mon Jul 07 2003 - 22:00:15 EST