[Bug tree-optimization/93781] Optimizer produces suboptimal code related to -ftree-vrp

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93781

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aldyh at gcc dot gnu.org,
                   |                            |amacleod at redhat dot com,
                   |                            |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
For the second testcase, I think we could in undefined_shift_range_check or its
2 callers intersect the value range of the last [lr]shift operand with the
range of [0, prec-1], and if that yields empty range, do what we use right now,
but if it narrows the op2 range to something smaller, use that in the
range_operator::fold_range call instead of op2.