[Bug target/80482] [7/8 Regression] vec_mul produces compilation error if 1 of its parms is const or volatile

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80482

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-04-22
                 CC|                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |7.0
            Summary|[7 Regression] vec_mul      |[7/8 Regression] vec_mul
                   |produces compilation error  |produces compilation error
                   |if 1 of its parms is const  |if 1 of its parms is const
                   |or volatile                 |or volatile
     Ever confirmed|0                           |1

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r237183.
I think best would be just to require that the types are compatible, like below
(swapped the TREE_CODE check because it is cheaper).
Or you can compare TYPE_MAIN_VARIANT (arg0_type) with TYPE_MAIN_VARIANT
(arg1_type), but that is less robust.

--- gcc/rs6000-c.c.jj   2017-03-29 07:11:23.000000000 +0200
+++ gcc/rs6000-c.c      2017-04-22 21:50:24.614009489 +0200
@@ -5596,10 +5596,10 @@ altivec_resolve_overloaded_builtin (loca
       tree arg1_type = TREE_TYPE (arg1);

       /* Both arguments must be vectors and the types must match.  */
-      if (arg0_type != arg1_type)
-       goto bad;
       if (TREE_CODE (arg0_type) != VECTOR_TYPE)
        goto bad;
+      if (!types_compatible_p (arg0_type, arg1_type))
+       goto bad;

       switch (TYPE_MODE (TREE_TYPE (arg0_type)))
        {
@@ -5610,8 +5610,8 @@ altivec_resolve_overloaded_builtin (loca
          case TImode:
            {
              /* For scalar types just use a multiply expression.  */
-             return fold_build2_loc (loc, MULT_EXPR, TREE_TYPE (arg0),
-                                       arg0, arg1);
+             return fold_build2_loc (loc, MULT_EXPR, TREE_TYPE (arg0), arg0,
+                                     fold_convert (TREE_TYPE (arg0), arg1));
            }
          case SFmode:
            {