[Bug tree-optimization/98221] [10 regression] Wrong unpack operation emitted in tree-ssa-forwprop.c

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98221

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
            Summary|[10/11 regression] Wrong    |[10 regression] Wrong
                   |unpack operation emitted in |unpack operation emitted in
                   |tree-ssa-forwprop.c         |tree-ssa-forwprop.c
      Known to work|                            |11.0
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-01-11
             Status|UNCONFIRMED                 |ASSIGNED

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

commit 300a3ce5c5695eb1a7c0476e9d1b45420a463248 (HEAD -> trunk, origin/master,
o
rigin/HEAD)
Author: Andreas Krebbel <krebbel@gcc.gnu.org>
Date:   Mon Jan 11 10:59:43 2021 +0100

    tree-optimization/98221 - fix wrong unpack operation used for big-endian

    The vec-abi-varargs-1.c testcase on IBM Z currently fails.

    While adding an SI mode vector to a DI mode vector the first is unpacked
using:

      _28 = BIT_INSERT_EXPR <{ 0, 0, 0, 0 }, _2, 0>;
      _34 = [vec_unpack_lo_expr] _28;

    However, on big endian targets lo refers to the right hand side of the
vector - in this case the zeroes.

    2021-01-11  Andreas Krebbel  <krebbel@linux.ibm.com>

            * tree-ssa-forwprop.c (simplify_vector_constructor): For
            big-endian, use UNPACK[_FLOAT]_HI.