[Bug c++/69756] Passing a multidimensional variable-length array into a lambda (by reference) causes an error

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69756

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code,
                   |                            |wrong-code
      Known to fail|                            |4.7.4, 6.0

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Ok, it's that way already during into-SSA.

It seems that we gimplify type sizes and end up using the main()s type size
in the lambda which is uninitialized there:

main()::<lambda()> (const struct __lambda0 * const __closure)
{
  sizetype D.2424;
  sizetype D.2425;
  int[0:D.2357][0:D.2347] * D.2426;
  int[0:(sizetype) __closure->__array.max][0:D.2357][0:D.2347] & array
[value-expr: (int[0:(sizetype) __closure->__array.max][0:D.2357][0:D.2347] &)
__closure->__array.ptr];

  {
    int i4;
    int i5;
    int i6;
    int output;
    typedef struct ._0 ._0;

    i4 = 1;
    i5 = 2;
    i6 = 3;
    D.2424 = D.2371 /[ex] 4;

D.2371 is defined in main().

This hits at invalid tree (type) sharing between functions and/or invalid
gimplification or un-nesting.  Not sure how lambdas are exactly implemented.