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Re: Performance booster patch (short patch, lengthly discussion)
- To: Richard Gorton <gorton at amt dot tay1 dot dec dot com>
- Subject: Re: Performance booster patch (short patch, lengthly discussion)
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Thu, 19 Mar 1998 21:18:03 -0700
- cc: egcs at cygnus dot com
- Reply-To: law at cygnus dot com
In message <9802171413.AA18589@liszt.amt.tay1.dec.com>you write:
>
> [Also posted in slightly different form to gcc2]
>
> Here's a small patch which improves performance on alpha and arm (the two
> architectures I tried this on) The diffs are based upon the
> egcs-980205 snapshot.
>
> diff -c fold-const.c fold-const.c.orig
> *** fold-const.c Mon Feb 16 15:29:58 1998
> --- fold-const.c.orig Sun Feb 1 06:47:57 1998
> ***************
> *** 1928,1936 ****
> primother = get_narrower (other, &unsignedpo);
>
> correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
> - /* Relax width constraint to permit mixing of unsigned/signed operation
> s */
> - correct_width += (TREE_UNSIGNED(arg0) | TREE_UNSIGNED(arg1)
> - | TREE_UNSIGNED(other));
> if (unsignedp1 == unsignedpo
> && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
> && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
> --- 1928,1933 ----
[ ... ]
We ended up picking up a patch which effectively does the same thing
from the gcc2 tree.
Thanks,
jeff