Division Optimization in match and simplify

Richard Biener richard.guenther@gmail.com
Thu Nov 5 17:24:00 GMT 2015


On November 5, 2015 2:40:30 PM GMT+01:00, Michael Matz <matz@suse.de> wrote:
>Hi,
>
>On Wed, 4 Nov 2015, Richard Biener wrote:
>
>> Ah, it was _left_ shift of negative values that ubsan complains
>about.
>
>Note that this is only for the frontend definition of shifts.  I don't
>see 
>why gimple shouldn't define it to the only sensible definition there
>is, 
>which also happens to be the one that all CPUs in the world implement 
>(well, those using two-complement representation at least).

Yeah, but front ends and back end are not separated enough to have both.

Richard.

>
>Ciao,
>Michael.




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