[Bug tree-optimization/113120] during GIMPLE pass: bitintlower ICE: SIGSEGV with _BitInt() at -O2

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113120

--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:efef8d7ff43c6c489fd6e7c52d71494d21324c87

commit r14-7001-gefef8d7ff43c6c489fd6e7c52d71494d21324c87
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Jan 8 13:58:28 2024 +0100

    lower-bitint: Fix up lowering of huge _BitInt 0 PHI args [PR113120]

    The PHI argument expansion of INTEGER_CSTs where bitint_min_cst_precision
    returns significantly smaller precision than the PHI result precision is
    optimized by loading the much smaller constant (if any) from memory and
    then either setting the remaining limbs to {} or calling memset with -1.
    The case where no constant is loaded (i.e. c == NULL) is when the
    INTEGER_CST is 0 or all_ones - in that case we can just set all the limbs
    to {} or call memset with -1 on everything.
    While for the all ones extension case that is what the code was already
    doing, I missed one spot in the zero extension case, where constricting
    the offset of the MEM_REF lhs of the = {} store it was using
unconditionally
    the byte size of c, which obviously doesn't work if c is NULL.  In that
case
    we want to use zero offset.

    2024-01-08  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/113120
            * gimple-lower-bitint.cc (gimple_lower_bitint): Fix handling of
very
            large _BitInt zero INTEGER_CST PHI argument.

            * gcc.dg/bitint-62.c: New test.