https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113301
Andrew Macleod <amacleod at redhat dot com> changed:
What |Removed |Added
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CC| |amacleod at redhat dot com
--- Comment #5 from Andrew Macleod <amacleod at redhat dot com> ---
(In reply to Jakub Jelinek from comment #4)
> Even then, I wonder why ranger doesn't figure this out.
> (x+1u) <= 2 ? x : 0
> must have a range [-1, 1] and [-1, 1] / [2, 2] range should be [0, 0], no?
its because there is no branch which is what drives ranger. At this point, we
aren't quite smart enough to completely evaluate the 2 operands of a
conditional as if they were actual branches.
ie
_1 = x_4(D) + 1;
_10 = (unsigned int) x_4(D);
_6 = _10 + 2;
_7 = _6 <= 2;
_2 = _7 ? _1 : 0;
if that were:
if (_6 <= 2)
_2 = _1
we'd recalculate _1 with the condition being (_6 <= 2) and we come upwith [-1,
1] for _1 instead of varying.
I'll have to look at whats involved in enhancing the fold code to invoke GORI
to reevaluate _1 if _7 is [1,1]. in theory is not too difficult... :-)
