bootstrap/8146: gcc 3.2 miscompiles gcc 2.95.3

[prj at po dot cwru dot edu]

>Number:         8146
>Category:       bootstrap
>Synopsis:       gcc 3.2 miscompiles gcc 2.95.3
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Fri Oct 04 10:46:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Paul Jarc
>Release:        3.2
>Organization:
>Environment:
System: Linux multivac.cwru.edu 2.4.19 #1 SMP Mon Aug 5 11:15:13 EDT 2002 i686 unknown
Architecture: i686

	
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ../gcc-3.2/configure --prefix=/package/host/localhost/gcc-3.2 --with-as=/package/host/localhost/gcc-3.2/conf/as --with-ld=/package/host/localhost/gcc-3.2/conf/ld --enable-threads --enable-libgcj --disable-nls
glibc 2.2.5
binutils 2.13
>Description:
	If I start with gcc 3.2 and try to bootstrap gcc 2.95.3, I get
	a bootstrap comparison failure.  The documentation says that this
	usually indicates that the host compiler (gcc 3.2 here) miscompiled
	gcc (2.95.3).
	Bootstrap comparison failure!
	cccp.o differs
	f/data.o differs
	f/target.o differs
	make[1]: *** [compare-lean] Error 1
	3.1 and 3.1.1 also fail to bootstrap 2.95.3.  IIRC, 3.1 had
	differences only in cccp.o.
	I suggest adding bootstrapping old versions to the pre-release
	testing procedure.  Having a buggy compiler is bad; having one
	that is buggy in such a way as to complicate downgrading to a
	not-known-to-me-to-be-buggy version is worse.
	(I was able to downgrade by doing "make install" after the failing
	"make bootstrap", and then using that incomplete 2.95.3 to do a
	successful bootstrap of a new 2.95.3.)
>How-To-Repeat:
	Build 2.95.3 using 3.2.  I think you already have the relevant
	source files. :)  Files from my build or installation
	directories of 3.2 or 2.95.3 are available on request.
>Fix:
	
>Release-Note:
>Audit-Trail:
>Unformatted: