Subject: Pentium gcc patch
To: None <port-i386@NetBSD.ORG>
From: Jeff Thieleke <>
List: port-i386
Date: 04/20/1996 04:52:59
I am interesting to see if anyone else has tried the Pentium Compiler 
Group's <> patch (pl9) for gcc 

Out of curiosity, I applied the patch to the NetBSD 1.1B's gcc, and was 
pleasantly surprised that it applied fairly easily, except for the 
configure stuff and the slightly rearranged NetBSD version of gcc (fixed 
by a few symlinks).  

If you believe the PCG, pgcc will generate much faster code - they 
estimate 5-35%.  My tests with gzip are a bit less optimistic, though.  
Using statically linked versions of gzip, one compiled with gcc and -O2 
-m486, and the other compiled with pgcc and -O2 -mpentium, I got a speed 
improvement of 2.4% for compressing (-9), and 11.4% for decompressing.  
(my data set was the port-i386 mailing list archives 0-150, and the timing 
was taking from /usr/bin/time). 

The real surprise was the file sizes.  I got adventurous and compiled a 
kernel...  Using the same configuration file and -O2, the gcc -m486 kernel 
was 947,986 bytes, while the pgcc -mpentium kernel was only 857,874!  
Overall, I've seen about a 5%-10% file size reduction, which is inline 
with the PCG's results.

I have been using the pgcc kernel for about a day now, and so far so good.  
pgcc is pretty flakely at -O6 (doesn't seem improve speed anyway), but it 
built itself to stage 3 at -O2, so I'm fairly confident at that 
optimization level. 

Jeff Thieleke