Re: [PATCH 1/24] make atomic_read() behave consistently on alpha
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2007-08-11 00:44:22
Also in:
linux-arch, lkml
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2007-08-11 00:44:22
Also in:
linux-arch, lkml
On Sat, Aug 11, 2007 at 02:38:40AM +0200, Segher Boessenkool wrote:
quoted
quoted
That means GCC cannot compile Linux; it already optimises some accesses to scalars to smaller accesses when it knows it is allowed to. Not often though, since it hardly ever helps in the cost model it employs.Please give an example code snippet + gcc version + arch to back this up.unsigned char f(unsigned long *p) { return *p & 1; }
This doesn't really matter since we only care about the LSB. Do you have an example where gcc reads it non-atmoically and we care about all parts? Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} [off-list ref] Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt