From jin@adv-pc-1.lbl.gov  Thu Feb 20 15:57:51 1997
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Date: Thu, 20 Feb 1997 15:34:34 -0800 (PST)
From: "Jin Guojun[ITG]" <jin@adv-pc-1.lbl.gov>
Reply-To: jin@adv-pc-1.lbl.gov
To: FreeBSD-gnats-submit@freebsd.org, iss-prog@adv-pc-1.lbl.gov
Subject: gcc version 2.7.2.1 C compiler slows down integer performance
X-Send-Pr-Version: 3.2

>Number:         2786
>Category:       gnu
>Synopsis:       gcc version 2.7.2.1 C compiler slows down integer performance
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Feb 20 16:00:01 PST 1997
>Closed-Date:    Mon Jan 10 06:25:50 PST 2000
>Last-Modified:  Mon Jan 10 06:26:53 PST 2000
>Originator:     Jin Guojun[ITG]
>Release:        FreeBSD 2.2-970215-GAMMA i386
>Organization:
>Environment:

	gcc version 2.7.2.1 under FreeBSD 2.2-GAMMA

>Description:

	gcc version 2.7.2.1 slows down the integer instruction performance
	by 1/3 (33%).
	For details, please read ftp://george.lbl.gov/pub/ccs/performance.ps
	table-6 on page 7. Compare MIPS on column 4-5,6, and 7-8.
	Column 4 is a pure 2.1.7 system (same hardware for column 5-6).
	Column 5 is a pure 2.2-GAMMA system.
	Column 6 is a 2.2-GAMMA system using 2.1.6 compiler (gcc version 2.6.3)

	Column 7 is a 2.2-GAMMA system using 2.1.6 compiler (gcc version 2.6.3)
	Column 8 is a pure 2.2-GAMMA system (same hardware for column 7).

>How-To-Repeat:

	I believe to wirte some integer arithmetic code can prove this.

>Fix:
	
	to use gcc version 2.6.3 for a temporary solution.

>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: phantom 
State-Changed-When: Mon Jan 10 06:25:50 PST 2000 
State-Changed-Why:  
Default compiler is upgraded to gcc 2.95.2 
>Unformatted:
