[Bug tree-optimization/126876] [17 regression] ice in ssa_range_in_phi since r17-3298

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126876

--- Comment #14 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Aldy Hernandez <[email protected]>:

https://gcc.gnu.org/g:92a49b653b21fc8cf55c114e24a83d6f40d19f2b

commit r17-3356-g92a49b653b21fc8cf55c114e24a83d6f40d19f2b
Author: Aldy Hernandez <[email protected]>
Date:   Mon Aug 17 14:51:59 2026 +0000

    testsuite: reproducers for PR126876

    ICE-on-valid at -O2 in the thread pass since r17-3298: the path
    query becomes the current query during fold_using_range::fold_stmt,
    match.pd's gimple_match_range_of_expr then queries it with a context
    statement resolved via gimple_match_ctx to SSA_NAME_DEF_STMT of a
    capture -- a statement from an arbitrary block.  internal_range_of_expr
    feeds gimple_bb (stmt) to range_defined_in_block, and for a PHI,
    ssa_range_in_phi resolves the incoming edge positionally via
    prev_bb () -- valid only when the PHI's block is the current path
    position.  Out of position, find_edge (prev, bb) is NULL (here
    prev == bb: the PHI's block is m_path[m_pos + 1]) and the
    EDGE_ABNORMAL checking assert's e_in->flags dereference segfaults.
    No abnormal edges are involved; the assert line is merely the first
    dereference -- the pre-assert PHI_ARG_DEF_FROM_EDGE would have
    crashed identically.

            PR tree-optimization/126876
            * gcc.dg/tree-ssa/pr126876.c: New test.