[Bug c++/53094] constexpr vector subscripting

[vincenzo.innocente at cern dot ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53094

--- Comment #9 from vincenzo Innocente <vincenzo.innocente at cern dot ch> 
2012-12-03 19:15:09 UTC ---
adding  it "helps"
   t = build_constructor (TREE_TYPE (t), n);
+  if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
+    t = fold (t);
   TREE_CONSTANT (t) = true;

unfortunately generates ICE for the class constructor at cp/tree.c:2712


struct Rot3 {
  typedef float T;
  typedef V4 Vec;
  Vec  axis[3];
  constexpr Rot3( V4 ix,  V4 iy,  V4 iz) :
    axis{ix,iy,iz}{}

  constexpr Rot3(T xx, T xy, T xz, T yx, T yy, T yz, T zx, T zy, T zz) :
    Rot3( (Vec){xx,xy,xz,0},
      (Vec){yx,yy,yz,0},
      (Vec){zx,zy,zz,0}
      ){}

};

constexpr Rot3 r2( (V4){0, 1 ,0,0}, (V4){0, 0, 1,0},(V4){1, 0, 0,0});
constexpr Rot3 r1( 0, 1 ,0, 0, 0, 1,  1, 0, 0);

ceVec.cc:26:46:   in constexpr expansion of ‘((Rot3*)(& r1))->Rot3::Rot3(0.0,
1.0e+0, 0.0, 0.0, 0.0, 1.0e+0, 1.0e+0, 0.0, 0.0)’
ceVec.cc:21:4:   in constexpr expansion of
‘((Rot3*)this)->Rot3::Rot3(Rot3::Vec{xx, xy, xz, 0.0f}, Rot3::Vec{yx, yy, yz,
0.0f}, Rot3::Vec{zx, zy, zz, 0.0f})’
ceVec.cc:26:46: internal compiler error: in cp_tree_equal, at cp/tree.c:2712
 constexpr Rot3 r1( 0, 1 ,0, 0, 0, 1,  1, 0, 0);