https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114589
Andrew Macleod <amacleod at redhat dot com> changed:
What |Removed |Added
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CC| |aldyh at gcc dot gnu.org
--- Comment #11 from Andrew Macleod <amacleod at redhat dot com> ---
(In reply to Richard Biener from comment #10)
>
> from pointer to unsigned long. Possibly IVOPTs replacing the pointer
> IV with an integer IV (but nothing else really) is the issue here.
>
Yes, this would be my guess. with pointers we make an attempt to track the
symbolic base in VRP, whereas with integers there is not usually a need. So
when it comes to the loop there is no attempt to track that the lower bound of
the loop/PHI is o_3...
Instead, we see a non-zero integral range. PHI analysis can detect that it is
increasing, but it has no way to recognize a starting base range.
Its possible when prange has points to analysis implemented it might be able to
determine something (ie look at what the integer is derived from, looking for a
cast in the past to determine a base) , but moving back and forth to an integer
certainly complicated things.
