Re: [avr-gcc-list] avr-gcc bug 18251 not resolved (ice-on-valid-code)

[E. Weddington]

Stephan Eisvogel wrote:

> Greetings,
>
> Bug 18251 as discussed in
>
>  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18251
>
> is  afaict  not fully resolved in gcc HEAD as of today. It compiles on
> 3.4.3 with no problems so this appears to be a 4.x regression.
>
> I  have  not filed a bug report with gcc bugzilla as I have never done
> this  and  I don't want to bug the developers with stupid errors on my
> part.  
It won't bother the developers, in fact, any reports at all help 
tremendously. You don't need to worry about it.

I would suggest that you go to that bug report and take all the 
information below and put it into the "Additional Comments" box and then 
save it. If you don't have a login name/password you'll have to create 
one; don't worry it's easy because the login is based on an email address.

It's *very* important to get this information in the bug report itself, 
otherwise stuff like this gets lost in all the email traffic.

Thanks
Eric



> The  code  snippet used to be part of an MD5 transform function
> but  I  have  stripped  it down to the point where it is still valid C
> code  but does not do anything useful any more. In this state removing
> any  of  the  remaining lines usually prevents the ICE from occurring,
> most notably the LPM macro (taken from avr-libc HEAD).
>
> Shall  I file this with bugzilla? And more importantly, what's causing
> it and how can I fix this?
>
> Cheers,
> Stephan
>
>
> The code snippet below yields the following ICE:
>
> $ avr-gcc -Os -mmcu=atmega162 -c test.c
> test.c: In function 'test':
> test.c:46: error: unable to find a register to spill in class 'POINTER_REGS'
> test.c:46: error: this is the insn:
> (insn 18 115 20 0 (set (reg/v:SI 56 [ a ])
>        (mem:SI (post_inc:HI (reg/f:HI 22 r22 [orig:59 D.1226 ] [59])) [2 S4 
> A8])) 14 {*movsi} (insn_list:REG_DEP_TRUE 115 (nil))
>    (expr_list:REG_INC (reg/f:HI 22 r22 [orig:59 D.1226 ] [59])
>        (nil)))
> test.c:46: internal compiler error: in spill_failure, at reload1.c:1897
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <URL:http://gcc.gnu.org/bugs.html> for instructions.
>
> Compiler version:
>
> $ avr-gcc -v
> Using built-in specs.
> Target: avr
> Configured with: ../configure --target=avr --prefix=/home/eisvogel/avr 
> --enable-languages=c,c++ --disable-nls
> Thread model: single
> gcc version 4.1.0 20050422 (experimental)
>
> --- TEST CASE START ---
>
> #define __LPM_enhanced__(addr)  \
> ({                              \
>    unsigned int __addr16 = (unsigned int)(addr); \
>    unsigned char __result;           \
>    __asm__                     \
>    (                           \
>        "lpm %0, Z" "\n\t"      \
>        : "=r" (__result)       \
>        : "z" (__addr16)        \
>    );                          \
>    __result;                   \
> })
>
>
> void test ( unsigned long *state )
> {
>        unsigned long a, b, c, d, temp;
>        unsigned char i;
>
>        a = state[0];
>        b = state[1];
>        c = state[2];
>        d = state[3];
>        
>        for ( i=0 ; i<2 ; i++ ) {
>
>                temp = a;
>                
>                switch ( i ) {
>                        case 1: temp += (((b) & (d)) | ((c) & (~d)));
>                }
>
>                temp += __LPM_enhanced__( 0 ); 
>
>                a = d;
>                d = c;
>                c = b;
>                b = temp;
>        }
>
>        state[0] += a;
>        state[1] += b;
>        state[2] += c;
>        state[3] += d;
> }
>
> --- TEST CASE END ---
>
>
>
>
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