[Bug c++/12856] New: Wrong code with -O1: register %sil

["nkoch at demig dot de" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12856

           Summary: Wrong code with -O1: register %sil
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: nkoch at demig dot de
                CC: gcc-bugs at gcc dot gnu dot org

FreeBSD entw-pr.demig 4.8-STABLE FreeBSD 4.8-STABLE #2: Mon Aug 4 12:45:05 CEST 
2003 root@entw-pr.demig:/usr/obj/usr/src/sys/ENTW-PR i386

Reading specs from /usr/local/lib/gcc-lib/i386-portbld-freebsd4.8/3.3.2/specs 
Configured with: ./..//gcc-3.3.2/configure --disable-nls 
--with-gxx-include-dir=/usr/local/lib/gcc-lib/i386-portbld-freebsd4.8/3.3.
2/include/c++/ --with-system-zlib --disable-shared --prefix=/usr/local 
i386-portbld-freebsd4.8 Thread model: posix gcc version 3.3.2 [FreeBSD]

g++33 -pipe -march=pentium -fwritable-strings -I. -I.. -I/usr/local/lib 
-D_REENTRANT -D_THREAD_SAFE -pthread -O1 -c -S -Wa,-L limit_c.cpp

In the generated assembly code I find the following line:
	cmp $0, %sil   

No problem if using -O0.

If wanted, I could send preprocessed source and assembly output
with -O0 and -O1.