[Bug target/123097] [16 Regression] [RISCV] [Miscompile] GCC - riscv64 target, miscompiles at -O3 since r16-5979

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123097

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Robin Dapp <rdapp@gcc.gnu.org>:

https://gcc.gnu.org/g:e8937196b2bdb0c7c7f967a4ddca3520e2db9b6b

commit r16-6288-ge8937196b2bdb0c7c7f967a4ddca3520e2db9b6b
Author: Robin Dapp <rdapp@ventanamicro.com>
Date:   Fri Dec 12 09:52:16 2025 +0100

    vect: Use type precision in reduction epilogue [PR123097].

    In the PR we extract non-existent bits/elements from a vector.  This is
    because we use TYPE_SIZE (vectype) for a boolean vector which returns 8
    instead of 4 for RVV's vector (4) <signed-boolean:1>.

    The patch uses TYPE_VECTOR_SUBPARTS instead and multiplies its result
    with vector_element_bits to get the proper number of elements and size.

            PR tree-optimization/123097

    gcc/ChangeLog:

            * tree-vect-loop.cc (vect_create_epilog_for_reduction):
            Calculate vector size by number of elements * bit size per
            element.

    gcc/testsuite/ChangeLog:

            * gcc.target/riscv/rvv/autovec/pr123097-run.c: New test.
            * gcc.target/riscv/rvv/autovec/pr123097.c: New test.