This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: GCC optimizes integer overflow: bug or feature?
Andrew Pinski wrote:
I don't have the number of times this shows up or how much it helps but
it does help out on being able to vectorize this loop.
Just to be clear, when I ask for quantitative data, it is precisely
data about "how much it helps". It is always easy enough to show
cases where the optimization does help the code.
All of these do show up in real code, and since loops are now more
important to optimize than anything else, well knowing the number of
iterations is very important.
Using "very" is usually a substitute for actual data, and that appears
to be the case here. What would make me confident that this optimization
is worth while is a message that says"
This test (hopefully one from a realistic example, or at least from a
real benchmark suite, and not just cooked up for demonstration) runs
in X seconds with the optimization and X+Y seconds without on bla
architecture.
That does not seem too much to ask :-)
Thanks,
Andrew Pinski