[avr-gcc-list] case statement broken in 4.1.2?

[Henning Paul]

Hi mailing list,

I have discovered a strange bug while trying to compile the firmware for the 
AVR-Doper from http://www.obdev.at/products/avrusb/avrdoper.html (an USB 
STK500 compatible HV and LV programmer). Using an if construction

#define SWITCH_START        if(0){
#define SWITCH_CASE(value)  }else if(cmd == (value)){
#define SWITCH_CASE2(v1,v2) }else if(cmd == (v1) || cmd == (v2)){
#define SWITCH_CASE3(v1,v2,v3) }else if(cmd == (v1) || cmd == (v2) || (cmd == 
v3)){
#define SWITCH_CASE4(v1,v2,v3,v4) }else if(cmd == (v1) || cmd == (v2) || cmd 
== (v3) || cmd == (v4)){
#define SWITCH_DEFAULT      }else{
#define SWITCH_END          }

the firmware works perfectly and no warning is produced:

address@hidden:~/Download/AVR-Doper.2006-10-23/firmware> make stk500protocol.o
avr-gcc -Wall -Os -Iusbdrv -I. -mmcu=atmega8 -DDEBUG_LEVEL=0 -c 
stk500protocol.c -o stk500protocol.o
stk500protocol.c: In function 'stkEvaluateRxMessage':
stk500protocol.c:137: warning: pointer targets in passing argument 1 
of 'strcpy_P' differ in signedness
stk500protocol.c:137: warning: pointer targets in passing argument 2 
of 'strcpy_P' differ in signedness

but if I use a case construction

#define SWITCH_START        switch(cmd){{
#define SWITCH_CASE(value)  }break; case (value):{
#define SWITCH_CASE2(v1,v2) }break; case (v1): case(v2):{
#define SWITCH_CASE3(v1,v2,v3) }break; case (v1): case(v2): case(v3):{
#define SWITCH_CASE4(v1,v2,v3,v4) }break; case (v1): case(v2): case(v3): 
case(v4):{
#define SWITCH_DEFAULT      }break; default:{
#define SWITCH_END          }}

the assembler throws a warning:

address@hidden:~/Download/AVR-Doper.2006-10-23/firmware> make stk500protocol.o
avr-gcc -Wall -Os -Iusbdrv -I. -mmcu=atmega8 -DDEBUG_LEVEL=0 -c 
stk500protocol.c -o stk500protocol.o
stk500protocol.c: In function 'stkEvaluateRxMessage':
stk500protocol.c:137: warning: pointer targets in passing argument 1 
of 'strcpy_P' differ in signedness
stk500protocol.c:137: warning: pointer targets in passing argument 2 
of 'strcpy_P' differ in signedness
/tmp/ccDpgAHu.s: Assembler messages:
/tmp/ccDpgAHu.s:147: Warning: expression dangerous with linker stubs
/tmp/ccDpgAHu.s:148: Warning: expression dangerous with linker stubs

and the firmware isn't working. I have contacted the programmer from obdev.at 
and he told me he didn't have these problems with GCC 3.4.x and considers 
this a bug of GCC 4.x.

The versions of GCC and as used by me are:

address@hidden:~/Download/AVR-Doper.2006-10-23/firmware> avr-gcc -v
Using built-in specs.
Target: avr
Configured 
with: ../configure --prefix=/opt/cross --with-local-prefix=/usr/local 
--infodir=/opt/cross/share/info --mandir=/opt/cross/share/man 
--libdir=/opt/cross/lib --libexecdir=/opt/cross/lib --enable-languages=c,c++ 
--enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.1.2 
--enable-ssp --disable-libssp --disable-libgcj --with-slibdir=/lib 
--with-system-zlib --enable-shared --enable-__cxa_atexit 
--enable-libstdcxx-allocator=new --disable-nls --disable-shared --target=avr 
--host=i586-suse-linux
Thread model: single
gcc version 4.1.2 20061115 (prerelease) (SUSE Linux)

address@hidden:~/Download/AVR-Doper.2006-10-23/firmware> avr-as --version
GNU assembler 2.17.50.0.5 20060927 (SUSE Linux)
Copyright 2005 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.
This assembler was configured for a target of `avr'.

Sources and assembler output for both cases are attached.

Thank you.

regards
Henning

stk500protocol.c
Description: Text Data

stk500protocol.s.if
Description: Text Data

stk500protocol.s.case
Description: Text Data