Do not ignore UNDEFINED ranges when determining PHI equivalences.
Do not ignore UNDEFINED name arguments when registering two-way equivalences
from PHIs.
PR tree-optimization/109564
gcc/
* gimple-range-fold.cc (fold_using_range::range_of_phi): Do no ignore
UNDEFINED range names when deciding if all PHI arguments are the same,
gcc/testsuite/
* gcc.dg/torture/pr109564-1.c: New testcase.
* gcc.dg/torture/pr109564-2.c: Likewise.
* gcc.dg/tree-ssa/evrp-ignore.c: XFAIL.
* gcc.dg/tree-ssa/vrp06.c: Likewise.
(cherry picked from commit
17aa9ddb34581855dd013745c8be27dda024de4a)