[Bug target/41751] New: bad code with arrays as local vars and no optimization

["sezeroz at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

static void R_EdgeDrawing (qboolean Translucent)
{
 edge_t ledges[NUMSTACKEDGES + ((CACHE_SIZE - 1) / sizeof(edge_t)) + 1];
 surf_t lsurfs[NUMSTACKSURFACES + ((CACHE_SIZE - 1) / sizeof(surf_t)) + 1];
..

(see attached r_main-1.i and r_main-1.s) is incorrectly compiled when
optimizations are turned off (no -O) with gcc-4.x series compilers on
x86_64. -O1, -O2, -O3 and -Os are fine with gcc-4.x, whereas gcc-3.4.6
(as shipped with fedora 10) is fine with or without optimizations.

If those vars are moved to the top of file as static (attached files
r_main-3.i and r_main-3.s), gcc-4.x up to gcc-4.4.3 behave correctly
without optimizations and the compiled program runs expectedly. gcc-3.4
is fine as before. gcc-4.5 is not tested.


-- 
           Summary: bad code with arrays as local vars and no optimization
           Product: gcc
           Version: 4.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sezeroz at gmail dot com
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41751