optimization/4081: "-O2 -march=k6" cflags are broken with gcc 3.0.1

[Jorn Baayen]

>Number:         4081
>Category:       optimization
>Synopsis:       "-O2 -march=k6" cflags are broken with gcc 3.0.1
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          ice-on-legal-code
>Submitter-Id:   net
>Arrival-Date:   Wed Aug 22 06:26:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     
>Release:        3.0.1
>Organization:
>Environment:
System: Linux orthanc 2.4.8-ac1 #3 Sun Aug 12 00:11:33 CDT 2001 i586 unknown
Architecture: i586
CPU: AMD K6-2 400
Libc: GNU libc 2.2.3
host: i586-pc-linux-gnu
build: i586-pc-linux-gnu
target: i586-pc-linux-gnu
configured with: ../gcc-3.0.1/configure --prefix=/usr --with-gxx-include-dir=/usr/include/g++ --enable-shared --enable-languages=c,c++,f77
>Description:
	GCC gives an ice on certain pieces of code when compiled with 
	"-O2 -march=k6", it doesn't with "-march=k6" alone.
>How-To-Repeat:
	Compile texinfo 4.0 with CFLAGS set to "-O2 -march=k6", gives the
	following ice:

	...
	gcc -DINFODIR=\"/usr/info\" -DLOCALEDIR=\"/usr/share/locale\" -DHAVE_CONFIG_H -I. -I../lib -I../intl -I.. -I.    -O2 -march=k6 -c info-utils.c
	info-utils.c: In function `printed_representation':
	info-utils.c:489: Unrecognizable insn:
	(insn 360 342 344 (parallel[ 
	            (set (reg:SI 1 edx [86])
        	        (const_int 0 [0x0]))
	            (clobber (reg:CC 17 flags))
        	] ) -1 (nil)
	    (expr_list:REG_UNUSED (reg:CC 17 flags)
        	(nil)))
	info-utils.c:489: Internal compiler error in insn_default_length, at insn-attrtab.c:223
	Please submit a full bug report,
	with preprocessed source if appropriate.
	See <URL: http://www.gnu.org/software/gcc/bugs.html > for instructions.
	make[2]: *** [info-utils.o] Error 1
	make[2]: Leaving directory `/home/jorn/texinfo-4.0/info'
	make[1]: *** [all-recursive] Error 1
	make[1]: Leaving directory `/home/jorn/texinfo-4.0'
	make: *** [all-recursive-am] Error 2
	[jorn@orthanc texinfo-4.0]$  

>Fix:
	Workaround is ofcourse to optimize with "-O2 -march=i586", as this
	works properly.
>Release-Note:
>Audit-Trail:
>Unformatted: