[PATCH] Make vector lowering use vectors of proper sign

[Richard Guenther]

I noticed when trying to fix PR52584 that vector lowering always
creates unsigned vector types.  The following fixes that, also
getting rid of the weird use of a langhook.

Bootstrapped and tested on x86_64-unknown-linux-gnu.

Richard.

2012-03-14  Richard Guenther  <rguent...@suse.de>

        PR middle-end/52584
        * tree-vect-generic.c (type_for_widest_vector_mode): Take
        element type instead of mode, use build_vector_type_for_mode
        instead of the langhook, build a vector of proper signedness.
        (expand_vector_operations_1): Adjust.

Index: gcc/tree-vect-generic.c
===================================================================
*** gcc/tree-vect-generic.c     (revision 185379)
--- gcc/tree-vect-generic.c     (working copy)
*************** expand_vector_operation (gimple_stmt_ite
*** 471,483 ****
                                    gimple_assign_rhs2 (assign), code);
  }
  
! /* Return a type for the widest vector mode whose components are of mode
!    INNER_MODE, or NULL_TREE if none is found.
!    SATP is true for saturating fixed-point types.  */
  
  static tree
! type_for_widest_vector_mode (enum machine_mode inner_mode, optab op, int satp)
  {
    enum machine_mode best_mode = VOIDmode, mode;
    int best_nunits = 0;
  
--- 471,483 ----
                                    gimple_assign_rhs2 (assign), code);
  }
  
! /* Return a type for the widest vector mode whose components are of type
!    TYPE, or NULL_TREE if none is found.  */
  
  static tree
! type_for_widest_vector_mode (tree type, optab op)
  {
+   enum machine_mode inner_mode = TYPE_MODE (type);
    enum machine_mode best_mode = VOIDmode, mode;
    int best_nunits = 0;
  
*************** type_for_widest_vector_mode (enum machin
*** 503,515 ****
    if (best_mode == VOIDmode)
      return NULL_TREE;
    else
!     {
!       /* For fixed-point modes, we need to pass satp as the 2nd parameter.  */
!       if (ALL_FIXED_POINT_MODE_P (best_mode))
!       return lang_hooks.types.type_for_mode (best_mode, satp);
! 
!       return lang_hooks.types.type_for_mode (best_mode, 1);
!     }
  }
  
  
--- 503,509 ----
    if (best_mode == VOIDmode)
      return NULL_TREE;
    else
!     return build_vector_type_for_mode (type, best_mode);
  }
  
  
*************** expand_vector_operations_1 (gimple_stmt_
*** 856,863 ****
    if (!VECTOR_MODE_P (TYPE_MODE (type)) && op)
      {
        tree vector_compute_type
!         = type_for_widest_vector_mode (TYPE_MODE (TREE_TYPE (type)), op,
!                                      TYPE_SATURATING (TREE_TYPE (type)));
        if (vector_compute_type != NULL_TREE
          && (TYPE_VECTOR_SUBPARTS (vector_compute_type)
              < TYPE_VECTOR_SUBPARTS (compute_type))
--- 850,856 ----
    if (!VECTOR_MODE_P (TYPE_MODE (type)) && op)
      {
        tree vector_compute_type
!         = type_for_widest_vector_mode (TREE_TYPE (type), op);
        if (vector_compute_type != NULL_TREE
          && (TYPE_VECTOR_SUBPARTS (vector_compute_type)
              < TYPE_VECTOR_SUBPARTS (compute_type))