[Bug tree-optimization/126536] [13/14/15/16/17 Regression] ICE with -funswitch-loops

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126536

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Andrew Macleod <[email protected]>:

https://gcc.gnu.org/g:977fd87bade47e7624d803ba0cc549d819c03fe1

commit r17-3206-g977fd87bade47e7624d803ba0cc549d819c03fe1
Author: Andrew MacLeod <[email protected]>
Date:   Fri Aug 7 13:23:40 2026 -0400

    Allow range invert to fail.

    Return a boolean from range invert() to handle cases where an inversion
    cannot be represented.

            PR tree-optimization/126536
            gcc/
            * gimple-range-edge.cc (calc_switch_ranges): Check that invert
worked.
            * gimple-range-op.cc (cfn_toupper_tolower::fold_range): Likewise.
            * range-op-ptr.cc (operator_equal::op1_range): Likewise.
            (operator_not_equal::op1_range): Likewise.
            * range-op.cc (operator_equal::op1_range): Likewise.
            (operator_not_equal::op1_range): Likewise.
            (operator_rshift::op1_range): Likewise.
            (operator_logical_not::fold_range): Likewise.
            * tree-ssa-loop-unswitch.cc (unswitch_predicate): Likewise.
            * value-range.cc (irange_bitmask::range_from_mask): Likewise.
            (prange::invert): Return bool for success/fail.
            (irange::invert): Likewise.
            (irange::snap_subranges): Check that invert worked.
            (range_tests_int_range_max): Confirm failed invert works.
            (range_tests_misc): Check invert return value.
            * value-range.h (irange::invert): Add boolean return value.
            (prange::invert): Add boolean return value.
            * vr-values.cc (simplify_switch_using_ranges): Check invert result.

            gcc/testsuite/
            * gcc.dg/pr126536-1.c: New.
            * gcc.dg/pr126536-2.c: New.