Daniel Berlin wrote:
> On Thu, 2005-05-12 at 10:01 -0600, Zan Lynx wrote:
> > I'm not subscribed to the list (please CC replies to me) and this isn't
> > a real bug report, just a sort of quick check to see if its a known
> > problem.
> >
> > When I compiled openssl-0.9.7g using -O3 and -ftree-loop-linear as
> > CFLAGS, openssl failed its self-tests for the MD2 code. Interestingly,
> > it succeeded at the tests for other algorithms.
> >
>
> -ftree-loop-linear uses the dependence analyzer which has a number of
> issues where it will claim things are legal that are not.
>
> You shouldn't expect -ftree-loop-linear to work on random code that you
> don't know anything about :)
> At least, not yet.
> Hopefully these should be fixed in 4.1
>
>
The loops that get interchanged are in the following function:
static void md2_block(MD2_CTX *c, const unsigned char *d)
{
register unsigned int t,*sp1,*sp2;
register int i,j;
unsigned int state[48];
sp1=c->state;
sp2=c->cksm;
j=sp2[16 -1];
for (i=0; i<16; i++)
{
state[i]=sp1[i];
state[i+16]=t=d[i];
state[i+32]=(t^sp1[i]);
j=sp2[i]^=S[t^j];
}
t=0;
for (i=0; i<18; i++)
{
for (j=0; j<48; j+=8)
{
t= state[j+ 0]^=S[t];
t= state[j+ 1]^=S[t];
t= state[j+ 2]^=S[t];
t= state[j+ 3]^=S[t];
t= state[j+ 4]^=S[t];
t= state[j+ 5]^=S[t];
t= state[j+ 6]^=S[t];
t= state[j+ 7]^=S[t];
}
t=(t+i)&0xff;
}
memcpy(sp1,state,16*sizeof(unsigned int));
OPENSSL_cleanse(state,48*sizeof(unsigned int));
}
It is failing on mainline with:
md2_dgst.c: In function 'md2_block':
md2_dgst.c:170: error: Definition in block 13 does not dominate use in block 9
for SSA_NAME: t_23 in statement:
t_143 = PHI <t_23(9), 0(3)>;
PHI argument
t_23
for PHI node
t_143 = PHI <t_23(9), 0(3)>;
md2_dgst.c:170: internal compiler error: verify_ssa failed.
after transformation in loop linear.
