Optimization failure
Jeffrey A Law
law@hurl.cygnus.com
Sun Feb 28 23:30:00 GMT 1999
In message < 01ef01be6367$8da402f0$237196c0@seaspace.com >you write:
> >I believe the way to fix this is to
> >
>
> So, you just gonna leave us hanging???? :)
Did it get cut off?
Hmmm, apparently so.
I believe the way to fix this problem is to perform reassociations on the
tree of comparisons.
ie, given:
((A || (c == 0x7f)) || (c == 0x80))
That can be reassociated into
(A) || ((c == 0x7f)) || (c == 0x80))
Which then turns into
(A) || (c >= 0x7f || c <= 0x80)
And so on for the entire comparison.
I believe it would need to be structured similar to simplify_plus_minus,
except that it would work on trees instead of rtl and would have to hook
into the range checking code.
jeff
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