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Re: ACATS c460008 and VRP (was: Bootstrap failure on trunk: x86_64-linux-gnu)
- From: Laurent GUERBY <laurent at guerby dot net>
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Cc: gcc at gcc dot gnu dot org
- Date: Thu, 02 Mar 2006 00:54:24 +0100
- Subject: Re: ACATS c460008 and VRP (was: Bootstrap failure on trunk: x86_64-linux-gnu)
- References: <10603012348.AA17328@vlsi1.ultra.nyu.edu>
On Wed, 2006-03-01 at 18:48 -0500, Richard Kenner wrote:
> It looks like this one needs overflow checking to pass (-gnato):
> ACATS should aways be run with -gnato since that's the only way to
> get the behavior mandated by RM. Why are we running it without it? Is
> this new? Certainly -gnato was used during validations.
On GCC we use -gnato on tests known to need it
(/gcc/testsuite/ada/acats/overflow.lst) since we want to test
flags the typical GCC/Ada user does use and not what official validation
requires (which is -gnato -gnatE IIRC).
VRP might now force us to update the overflow list but I'm not sure
about switching to a full -gnato everywhere.
> Richard, Arnaud, could you check amongst GNAT experts if for such
> types (non power of two modulus), it's not worth enabling overflow
> checks by default now that we have VRP doing non trivial
> optimisations? People using non power of two modulus are not caring
> for performance anyway, so having a compliant implementation by
> default won't harm.
> Hardly worth writing the code to bother with that given how rare
> such things are ...