[Bug c/16563] New: The compiler doesnt the necessary push/restore of r18/r19

["baphomed at lycos dot de" <gcc-bugzilla@gcc.gnu.org>]

void  testfunc32(unsigned long);
void  testfunc16(int);
void testfunc8(char);

void testfunc(unsigned int a,char b,char c,unsigned long d)
{
        testfunc16(a);
        testfunc8(10);
        testfunc8(b);
        testfunc16(11);
        testfunc8(c);
        testfunc8(6);
        testfunc32(d);
}


void test()
{
testfunc(0xabcd,10,11,0xabacadae);
}


Compile the code with :

avr-gcc -c -Os file.c

Now we may look at the produced assembler directives.
This is the call to testfunc32():

mov     r25, r19
mov     r24, r18
mov     r23, r17
mov     r22, r16
rcall   testfunc32

All the other functions called before are free to change the content of 
r18/r19 wich contain the MSW of argument d.
The possibly modified value of d ist passed to testfunc32().

The gcc is configured with:
 --prefix=/usr/local/ --target=avr --enable-languages=c,c++ --disable-nls

-- 
           Summary: The compiler doesnt the necessary push/restore of
                    r18/r19
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: baphomed at lycos dot de
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux
GCC target triplet: avr


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16563