------- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni
dot cz 2004-12-31 01:29 -------
Subject: Re: [4.0 Regression] not using do-loop for some loops
> (In reply to comment #3)
> What I don't understand is why this was fine in 3.3.2 and not in 4.0.0 by the
> new do-loop.
Because the analysis in 3.3.2 is buggy. Doloop pattern is used even in the
following case (in that there is no problem with undefined behavior):
void
f (unsigned n)
{
unsigned k;
for(k = 3;k <= n;k++)
{
}
}
Which is a misscompilation in case n == ~0.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19210
