tree-optimization/107672 - avoid vector mode type_for_mode call

The following avoids using type_for_mode on vector modes which might
not work for all frontends.  Instead we look for the inner mode
type and use build_vector_type_for_mode instead.

	PR tree-optimization/107672
	* tree-vect-stmts.cc (supportable_widening_operation): Avoid
	type_for_mode on vector modes.
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index bc0ef13..b35b986 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -12195,9 +12195,15 @@
 	intermediate_type
 	  = vect_halve_mask_nunits (prev_type, intermediate_mode);
       else
-	intermediate_type
-	  = lang_hooks.types.type_for_mode (intermediate_mode,
-					    TYPE_UNSIGNED (prev_type));
+	{
+	  gcc_assert (VECTOR_MODE_P (intermediate_mode));
+	  tree intermediate_element_type
+	    = lang_hooks.types.type_for_mode (GET_MODE_INNER (intermediate_mode),
+					      TYPE_UNSIGNED (prev_type));
+	  intermediate_type
+	    = build_vector_type_for_mode (intermediate_element_type,
+					  intermediate_mode);
+	}
 
       if (VECTOR_BOOLEAN_TYPE_P (intermediate_type)
 	  && VECTOR_BOOLEAN_TYPE_P (prev_type)