Re: [PATCH] [2.5] asm-generic/atomic.h and changes to arm, parisc, mips, m68k, sh, cris to use it

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Thu Aug 08 2002 - 19:11:11 EST

On Thu, 2002-08-08 at 23:40, Luca Barbieri wrote:
> > The compiler can cache the value in a register
> It shouldn't since it is volatile and the machine has instructions with
> memory operands.

I'm curious what part of C99 guarantees that it must generate

        add 1 to memory

not

        load memory
        add 1
        store memory

It certainly guarantees not to cache it for use next statement, but does
it actually persuade the compiler to use direct operations on memory ?

I'm not a C99 language lawyer but genuinely curious

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