EGCS-971016: i686 Linux vs. SparcULTRA Solaris

[Teemu Torma <tot at trema dot com>]

    From:  Fred Richardson <frichard@bbn.com>
    Date:  Thu, 16 Oct 1997 23:27:00 -0400

    The flags used for compiling on the Ultra were:
        -mcpu=ultrasparc -funsigned-char -fno-exceptions -O6
        -finline-functions -ffast-math -fomit-frame-pointer -funroll-loops 
    
This may be a bit off from the topic, but

It seems that -mcpu=ultrasparc generates sometimes slower code 
than -mcpu=supersparc, and gcc 2.7.2.1 is faster than egcs.

I ran some speed tests last week using Eric Young's libdes `speed'
program.  These were the results, without haifa, 
on Sun Enterprice 450 (248Mhz UltraSparc).  Of course this kind
of test is not a good general speed test, but still...

EGCS 971008 -O3 -mcpu=supersparc

set_key       per sec =    212606.48 (  4.7uS)
DES ecb bytes per sec =   2930562.93 (  2.7uS)
DES cbc bytes per sec =   2909686.20 (  2.7uS)
crypt         per sec =     12788.55 ( 78.2uS)

EGCS 971008 -O3 -mcpu=ultrasparc

set_key       per sec =    231505.91 (  4.3uS)
DES ecb bytes per sec =   3043186.47 (  2.6uS)
DES cbc bytes per sec =   3118386.32 (  2.6uS)
crypt         per sec =     12224.42 ( 81.8uS)

GCC 2.7.2.1 -O3 -msupersparc

set_key       per sec =    245225.03 (  4.1uS)
DES ecb bytes per sec =   3212060.54 (  2.5uS)
DES cbc bytes per sec =   3218404.89 (  2.5uS)
crypt         per sec =     13785.99 ( 72.5uS)

Quick analysis with quantify revealed that egcs spends more time
when doing shifting, or'ing, and'ing etc.  I guess something must
be broken in the optimizer.

Teemu