[PATCH] vect: Vectorize via libfuncs

[Andrew Stubbs]

This patch allows vectorization when operators are available as 
libfuncs, rather that only as insns.

This will be useful for amdgcn where we plan to vectorize loops that 
contain integer division or modulus, but don't want to generate inline 
instructions for the division algorithm every time.

The change should have not affect architectures that do not define 
vector-mode libfuncs.

OK for mainline?

Andrewvect: vectorize via libfuncs

This patch allows vectorization when the libfuncs are defined.

gcc/ChangeLog:

        * tree-vect-generic.cc: Include optabs-libfuncs.h.
        (get_compute_type): Check optab_libfunc.
        * tree-vect-stmts.cc: Include optabs-libfuncs.h.
        (vectorizable_operation): Check optab_libfunc.

diff --git a/gcc/tree-vect-generic.cc b/gcc/tree-vect-generic.cc
index b7d4a919c55..4d784a70c0d 100644
--- a/gcc/tree-vect-generic.cc
+++ b/gcc/tree-vect-generic.cc
@@ -44,6 +44,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimple-fold.h"
 #include "gimple-match.h"
 #include "recog.h"             /* FIXME: for insn_data */
+#include "optabs-libfuncs.h"
 
 
 /* Build a ternary operation and gimplify it.  Emit code before GSI.
@@ -1714,7 +1715,8 @@ get_compute_type (enum tree_code code, optab op, tree 
type)
       machine_mode compute_mode = TYPE_MODE (compute_type);
       if (VECTOR_MODE_P (compute_mode))
        {
-         if (op && optab_handler (op, compute_mode) != CODE_FOR_nothing)
+         if (op && (optab_handler (op, compute_mode) != CODE_FOR_nothing
+                    || optab_libfunc (op, compute_mode)))
            return compute_type;
          if (code == MULT_HIGHPART_EXPR
              && can_mult_highpart_p (compute_mode,
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index a7acc032d47..71a8cf2c6d4 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -56,6 +56,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimple-fold.h"
 #include "regs.h"
 #include "attribs.h"
+#include "optabs-libfuncs.h"
 
 /* For lang_hooks.types.type_for_mode.  */
 #include "langhooks.h"
@@ -6528,8 +6529,8 @@ vectorizable_operation (vec_info *vinfo,
                              "no optab.\n");
          return false;
        }
-      target_support_p = (optab_handler (optab, vec_mode)
-                         != CODE_FOR_nothing);
+      target_support_p = (optab_handler (optab, vec_mode) != CODE_FOR_nothing
+                         || optab_libfunc (optab, vec_mode));
     }
 
   bool using_emulated_vectors_p = vect_emulated_vector_p (vectype);