This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: DImode speedup on i386
- To: Jeffrey A Law <law at cygnus dot com>
- Subject: Re: DImode speedup on i386
- From: Bernd Schmidt <crux at pool dot informatik dot rwth-aachen dot de>
- Date: Fri, 20 Feb 1998 11:35:43 +0100 (MET)
- cc: egcs at cygnus dot com, scox at cygnus dot com
> One general note -- you have to be *extremely* careful defining DImode
> patterns on the x86 due to the bad interactions with register
> reloading.
When the patch was written, I simply used the constraints from the addi3/subdi3
patterns to avoid problems.
Since it's about a year old (I've tried a couple of times to get it into
gcc2, without success), it's quite possible that things have changed. I'll
check that and implement Richard Henderson's suggestion, and send an updated
patch.
Bernd