This is the mail archive of the
libc-ports@sources.redhat.com
mailing list for the libc-ports project.
Re: Make fma use of Dekker and Knuth algorithms use round-to-nearest (bug 14796)
- From: Richard Henderson <rth at twiddle dot net>
- To: "Joseph S. Myers" <joseph at codesourcery dot com>
- Cc: libc-alpha at sourceware dot org, David Miller <davem at davemloft dot net>, libc-ports at sourceware dot org
- Date: Tue, 06 Nov 2012 11:26:09 -0800
- Subject: Re: Make fma use of Dekker and Knuth algorithms use round-to-nearest (bug 14796)
- References: <Pine.LNX.4.64.1211020212060.13462@digraph.polyomino.org.uk>
On 2012-11-01 19:14, Joseph S. Myers wrote:
> + libc_feupdateenv (&env);
> + /* Ensure that round-to-nearest value of z + m1 is not
> + reused. */
> + asm volatile ("" : "=m" (z) : "m" (z));
We have math_opt_barrier and math_force_eval.
We should use them and not spread more raw asms.
I know there are plenty of other existing instances
that should also be fixed, but we shouldn't add more.
Otherwise the actual logic looks ok.
r~