Array reuse failure: threat or menace?

Bugzilla Link	360
Created on	May 10, 2007 20:50
Resolution	REMIND
Resolved on	May 15, 2007 11:52
Version	1.00beta
OS	Linux
Architecture	PC

Extended Description

The following function has the interesting property that, when compiled
with -DFAST, it runs about 100X faster. Visual inspection at -b11 suggests 
that the problem appears to be, at least
in part, a failure of the "r = r + val" code to see that it could work in place
on r, rather than allocating a new array.
--------------cut here------------
use Array: all;
use String: {tochar,to_string,strtod,sprintf};
use StdIO: all;
int main()
{
 n = 1000000;
 r=[0];
 vec = iota( n) ;
lim  = (shape(vec)[[0]])-1;
for(i=0; i <= lim; i++){
 val = vec[i];
#ifdef  FAST
 r = modarray(r, [0], r[0] + val);
#else
 r = r + val;
#endif
 }
print(sum(r));
return(0);
}