[Bug c++/92745] [9 Regression] Initializing array with vec4 results in compile error

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92745

--- Comment #12 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jason Merrill
<ja...@gcc.gnu.org>:

https://gcc.gnu.org/g:c890c9650f3c4b1be1f39eabb74b438c033a8c08

commit r9-8294-gc890c9650f3c4b1be1f39eabb74b438c033a8c08
Author: Marek Polacek <pola...@redhat.com>
Date:   Fri Dec 20 23:30:04 2019 +0000

    PR c++/92745 - bogus error when initializing array of vectors.

    In r268428 I changed reshape_init_r in such a way that when it sees
    a nested { } in a CONSTRUCTOR with missing braces, it just returns
    the initializer:
    +     else if (COMPOUND_LITERAL_P (stripped_init)
    ...
    +         ++d->cur;
    +         gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (stripped_init));
    +         return init;

    But as this test shows, that's incorrect: if TYPE is an array, we need
    to proceed to reshape_init_array_1 which will iterate over the array
    initializers:
     6006   /* Loop until there are no more initializers.  */
     6007   for (index = 0;
     6008        d->cur != d->end && (!sized_array_p || index <=
max_index_cst);
     6009        ++index)
     6010     {
    and update d.cur accordingly.  In other words, when reshape_init gets

    {{col[0][0], col[1][0], col[2][0], col[3][0]},
     {col[0][1], col[1][1], col[2][1], col[3][1]},
     {col[0][2], col[1][2], col[2][2], col[3][2]},
     {col[0][3], col[1][3], col[2][3], col[3][3]}}

    we recurse on the first element:
      {col[0][0], col[1][0], col[2][0], col[3][0]}
    and we can't just move d.cur to point to
      {col[0][1], col[1][1], col[2][1], col[3][1]}
    and return; we need to iterate, so that d.cur ends up being properly
    updated, and after all initializers have been seen, points to d.end.
    Currently we skip the loop, wherefore we hit this:

     6502   /* Make sure all the element of the constructor were used.
Otherwise,
     6503      issue an error about exceeding initializers.  */
     6504   if (d.cur != d.end)
     6505     {
     6506       if (complain & tf_error)
     6507         error ("too many initializers for %qT", type);
     6508       return error_mark_node;
     6509     }

    gcc/cp/ChangeLog
    2019-12-19  Marek Polacek  <pola...@redhat.com>

        PR c++/92745 - bogus error when initializing array of vectors.
        * decl.c (reshape_init_r): For a nested compound literal, do
        call reshape_init_{class,array,vector}.

    gcc/testsuite/ChangeLog
    2019-12-19  Marek Polacek  <pola...@redhat.com>
            Jakub Jelinek  <ja...@redhat.com>

        PR c++/92745 - bogus error when initializing array of vectors.
        * g++.dg/cpp0x/initlist118.C: New test.
        * g++.dg/cpp0x/initlist118.C: Add -Wno-psabi -w to dg-options.