begin Gabriel Rosa <[EMAIL PROTECTED]> > On Wed, 27 Feb 2002, Peter Jay Salzman wrote: > > > another optimization question: > > > > int n = 5; > > for (i=0; i<n; ++i) > > > > can gcc unroll this loop the way it can (for instance) > > > > #define N 5 > > for (i=0; i<N; ++i) > > Refer to previous answer. > if you use -funroll-all-loops, yes. i realized that i wrote that email rather stupidly.
just to be clear, i know that you can unroll a loop when testing the iterator against a macro. i was asking about a simple variable assignment like int n=2; for (i=0; i<n; ++i) so i assume your answer would be "no" for -funroll-loops. the reason why i'm asking is that this is completely deterministic, and a compiler can know, with certainty, that this loop will iterate over 0 and 1. that is, you can know this at compile time, before executing any code. clearly, this ISN'T deterministic: int n=2; MyFunction(&n); for (i=0; i<n; ++i) but certainly, this is: int n=2; for (i=0; i<n; ++i) pete _______________________________________________ vox-tech mailing list [EMAIL PROTECTED] http://lists.lugod.org/mailman/listinfo/vox-tech