>Number:         6795
>Category:       bin
>Synopsis:       egcs 1.1.1 doesn't compile freelip with optimisation
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people (Utility Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jan 12 14:05:00 1999
>Last-Modified:
>Originator:     Simon Burge
>Organization:
	IBM Global Services Australia
>Release:        NetBSD-current January 8, 1999.
>Environment:
System: NetBSD simonpc 1.3I NetBSD 1.3I (SIMONPC) #0: Thu Jan 7 16:09:49 EST 1999 root@simonpc:/tmp/SIMONPC i386
gcc version egcs-2.91.60 19981201 (egcs-1.1.1 release)


>Description:
	Trying to compile freelip (a large integer package) with egcs
	results in a program that seems to contain extremely inefficent
	code in some sections.  This occurs on both an i386 and a pmax
	both running -current and using "gcc version egcs-2.91.60
	19981201 (egcs-1.1.1 release)"

	Compiling on both a pmax and an i386 running 1.3.3 with "gcc
	version 2.7.2.2+myc2" result in a working program.

>How-To-Repeat:
	Try to compile freelip (available at
	ftp://ftp.ox.ac.uk/pub/math/freelip/freelip_1.1.tar.gz) with
	ecgs with either -O or -O2.  Here's some results:

	gcc 2.7.2.2+myc2 on -current i386:

		...

		timing SINGLE_MUL = 1, PLAIN = 0, KARAT = 0

				59bit   179bit  299bit  419bit  539bit
				------- ------- ------- ------- -------
		59bit:           0.020   0.040   0.080   0.110   0.130
		179bit:                  0.030   0.070   0.110   0.160
		299bit:                          0.030   0.100   0.150
		419bit:                                  0.040   0.100
		539bit:                                          0.050

		...
		23.121u 0.049s 0:23.23 99.6%    0+0k 0+1io 0pf+0w


	gcc version egcs-2.91.60 19981201 (egcs-1.1.1 release) on -current i386:

		...

		timing SINGLE_MUL = 1, PLAIN = 0, KARAT = 0

				59bit   179bit  299bit  419bit  539bit
				------- ------- ------- ------- -------
		59bit:          62.780  210.670 374.800 443.660 853.460
		179bit:                  0.030   0.080   0.130   0.170
		299bit:                          0.360   0.790   2.290
		419bit:                                 16315.920^C
		50459.436u 5.499s 14:01:16.02 14.8%     0+0k 0+0io 30pf+0w

	The timing for each element is the time taken in seconds.  This
	is the seventh test out of nine - the previous six tests seem to
	complete ok.  Similar results (but with larger numbers :-) occur
	for the pmax too.

>Fix:
	None given - "Don't use -O or -O2" doesn't quite cut it,
	especially for numberical programs.  I will try to narrow down
	to a chunck of code that shows the problem, but freelip is a
	large package (the library is one 11829 line .c file and the
	driver program whose results are shown above is 5290 lines).
>Audit-Trail:
>Unformatted: