[Bug tree-optimization/123776] [16 Regression] ICE in execute_todo in gfortran.dg/assumed_rank_bounds_3.f90 with -O3 -march=armv9-a+sve2 -msve-vector-bits=128 -mmax-vectorization -mautovec-preference=sve-only

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123776

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:

https://gcc.gnu.org/g:716127795d95f96af7b19ef7d3ca8cfd80f32686

commit r16-6998-g716127795d95f96af7b19ef7d3ca8cfd80f32686
Author: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
Date:   Thu Jan 22 22:04:59 2026 -0800

    gimple-fold: Fix handling of vdefs for MASK_LOAD_LANES replacement
[PR123776]

    This was found when I was running the gcc testsuite with some SVE options
to
    enable SVE only vectorization and enable it always.
    After r16-5984-gcee0a9dd2700b9 and r16-6918-g46a3355c7f1656, we would fold:
      # .MEM_696 = VDEF <.MEM_695>
      vect_array.781 = .MASK_LOAD_LANES (vectp_this.772_515, 64B,
loop_mask_511, { 0, 0 });
    into:
      vect_array.781 = {};

    But since this was originally a "load" we don't copy the vdef. Some passes
    like fre will not cause a TODO_update_ssa to happen so we hit an assert
    which basically says the we should have done an update_ssa.
    While we could do an update_ssa, the better fix is to copy the vdef from
    the old statement to the new one before doing the gsi_replace. When we
    know this will be a store (in the !is_gimple_reg case). And then we have
    kept the vop up to date and don't need to do an update_ssa.

    Pushed as obvious after a build and test on aarch64-linux-gnu.

            PR tree-optimization/123776

    gcc/ChangeLog:

            * gimple-fold.cc (gimple_fold_partial_load_store): Copy
            the vdef from the old statement to the new statement of a
            load that is also a store to non gimple_reg.

    Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>