Re: shift/extract SHIFT_COUNT_TRUNCATED combine bug

[Segher Boessenkool]

On Tue, Jan 13, 2015 at 10:51:27AM +0100, Richard Biener wrote:
> IMHO SHIFT_COUNT_TRUNCATED should be removed and instead
> backends should provide shift patterns with a (and:QI ...) for the
> shift amount which simply will omit that operation if suitable.

Note that that catches less though, e.g. in

int f(int x, int n) { return x << ((2*n) & 31); }

without SHIFT_COUNT_TRUNCATED it will try to match an AND with 30,
not with 31.


Segher