[Bug c++/92745] [8/9/10 Regression] Initializing array with vec4 results in compile error

[mpolacek at gcc dot gnu.org]

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

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Author: mpolacek
Date: Fri Dec 20 23:30:04 2019
New Revision: 279686

URL: https://gcc.gnu.org/viewcvs?rev=279686&root=gcc&view=rev
Log:
        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     }

        * decl.c (reshape_init_r): For a nested compound literal, do
        call reshape_init_{class,array,vector}.

        * g++.dg/cpp0x/initlist118.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/initlist118.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl.c
    trunk/gcc/testsuite/ChangeLog