[Bug target/122627] [16 Regression] RISC-V rv64gcvb: ICE at -O0 during RTL pass: reload

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122627

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

https://gcc.gnu.org/g:2ea9d663650fdcd7f8350e743047e72fe25d0a99

commit r16-5243-g2ea9d663650fdcd7f8350e743047e72fe25d0a99
Author: Jeff Law <jlaw@ventanamicro.com>
Date:   Thu Nov 13 08:51:40 2025 -0700

    [RISC-V][PR rtl-optimization/122627] Yet another fix in IRA equivalence
array handling

    Yup, yet another out of bounds access into the equivalence array.

    In this case we had an out of bounds write, which corrupted the heap
leading to
    the fault.

    Given this is the 3rd such issue in this space in recent history and the
second
    in this loop within LRA within a week or so, I looked for a solution that
would
    cover the whole loop rather than another spot fix.

    The good news is this loop runs after elimination, so we can just expand
the
    equivalence array after elimination and all the right things should happen.
    This also allows removal of the spot fix I did last week (which I did
    backtest).  I didn't have a testcase for the bug in this space I fixed a
couple
    months ago (and the artifacts from that build are certainly gone from my
tester
    by now).

    Bootstrapped and regression tested on x86.  Also verified the RISC-V
failures
    in this bz and bz122321 are fixed.

    Given this is a refinement & simplification of a prior fix, I'm going to
take
    some slight leeway to push the fix forward now.

            PR rtl-optimization/122627
    gcc/
            * lra-constraints.cc (update_equiv): Remove patch from last week
            related to pr122321.
            (lra_constraints): Expand the equivalence array after eliminations
            are complete.

    gcc/testsuite/

            * gcc.target/riscv/rvv/autovec/pr122627.c: New test.