[Bug tree-optimization/44885] [4.6 regression] miscompilation of gnat.dg/aliasing3.adb after mem-ref2

["ebotcazou at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #2 from ebotcazou at gcc dot gnu dot org  2010-07-09 13:05 -------
> Can you elaborate?  The relevant type for the MEM_REF is always that of the
> base object, which is either a dereference (thus, of sth addressable) or
> a decl (which can't be non-aliased as well, no?).

In 144t.optimized there is:

  aliasing3_pkg__pointer.18_1->a[1]{lb: 1 sz: 4} = 5;
  D.2290_6 = MEM[(integer *)&aliasing3_pkg__block].a[1]{lb: 1 sz: 4};

and the type (integer *) is wrong.  But you're right, it's probably wrong
before since there is in 014t.veclower:

  aliasing3_pkg__pointer.18 = aliasing3_pkg__pointer;
  aliasing3_pkg__pointer.18->a[1]{lb: 1 sz: 4} = 5;
  aliasing3_pkg.test (&aliasing3_pkg__block.a);

and in 022t.cleanup_cfg:

  aliasing3_pkg__pointer.18 = aliasing3_pkg__pointer;
  aliasing3_pkg__pointer.18->a[1]{lb: 1 sz: 4} = 5;
  aliasing3_pkg.test.isra (&aliasing3_pkg__block.a[1]{lb: 1 sz: 4});

So it looks like IPA-SRA breaks TYPE_NONALIASED_COMPONENT here because it takes
the address of a non-aliased component.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |tree-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44885