Add gimple_build_vector* helpers

This patch adds gimple-fold.h equivalents of build_vector and
build_vector_from_val.  Like the other gimple-fold.h routines
they always return a valid gimple value and add any new
statements to a given gimple_seq.  In combination with later
patches this reduces the number of force_gimple_operands.

2017-09-14  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* gimple-fold.h (gimple_build_vector_from_val): Declare, and provide
	an inline wrapper that provides a location.
	(gimple_build_vector): Likewise.
	* gimple-fold.c (gimple_build_vector_from_val): New function.
	(gimple_build_vector): Likewise.
	* tree-vect-loop.c (get_initial_def_for_reduction): Use the new
	functions to build the initial value.  Always return a gimple value.
	(get_initial_defs_for_reduction): Likewise.  Only compute
	neutral_vec once.
	(vect_create_epilog_for_reduction): Don't call force_gimple_operand or
	vect_init_vector on the results from get_initial_def(s)_for_reduction.
	(vectorizable_induction): Use gimple_build_vector rather than
	vect_init_vector.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r252762

gcc/ChangeLog

@@ -2,6 +2,24 @@
 	    Alan Hayward  <alan.hayward@arm.com>
 	    David Sherwood  <david.sherwood@arm.com>
 
+	* gimple-fold.h (gimple_build_vector_from_val): Declare, and provide
+	an inline wrapper that provides a location.
+	(gimple_build_vector): Likewise.
+	* gimple-fold.c (gimple_build_vector_from_val): New function.
+	(gimple_build_vector): Likewise.
+	* tree-vect-loop.c (get_initial_def_for_reduction): Use the new
+	functions to build the initial value.  Always return a gimple value.
+	(get_initial_defs_for_reduction): Likewise.  Only compute
+	neutral_vec once.
+	(vect_create_epilog_for_reduction): Don't call force_gimple_operand or
+	vect_init_vector on the results from get_initial_def(s)_for_reduction.
+	(vectorizable_induction): Use gimple_build_vector rather than
+	vect_init_vector.
+
+2017-09-14  Richard Sandiford  <richard.sandiford@linaro.org>
+	    Alan Hayward  <alan.hayward@arm.com>
+	    David Sherwood  <david.sherwood@arm.com>
+
 	* target.h (vec_perm_indices): New typedef.
 	(auto_vec_perm_indices): Likewise.
 	* optabs-query.h: Include target.h

gcc/gimple-fold.c

@@ -7058,6 +7058,58 @@ gimple_convert_to_ptrofftype (gimple_seq *seq, location_t loc, tree op)
   return gimple_convert (seq, loc, sizetype, op);
 }
 
+/* Build a vector of type TYPE in which each element has the value OP.
+   Return a gimple value for the result, appending any new statements
+   to SEQ.  */
+
+tree
+gimple_build_vector_from_val (gimple_seq *seq, location_t loc, tree type,
+			      tree op)
+{
+  tree res, vec = build_vector_from_val (type, op);
+  if (is_gimple_val (vec))
+    return vec;
+  if (gimple_in_ssa_p (cfun))
+    res = make_ssa_name (type);
+  else
+    res = create_tmp_reg (type);
+  gimple *stmt = gimple_build_assign (res, vec);
+  gimple_set_location (stmt, loc);
+  gimple_seq_add_stmt_without_update (seq, stmt);
+  return res;
+}
+
+/* Build a vector of type TYPE in which the elements have the values
+   given by ELTS.  Return a gimple value for the result, appending any
+   new instructions to SEQ.  */
+
+tree
+gimple_build_vector (gimple_seq *seq, location_t loc, tree type,
+		     vec<tree> elts)
+{
+  unsigned int nelts = elts.length ();
+  gcc_assert (nelts == TYPE_VECTOR_SUBPARTS (type));
+  for (unsigned int i = 0; i < nelts; ++i)
+    if (!TREE_CONSTANT (elts[i]))
+      {
+	vec<constructor_elt, va_gc> *v;
+	vec_alloc (v, nelts);
+	for (i = 0; i < nelts; ++i)
+	  CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, elts[i]);
+
+	tree res;
+	if (gimple_in_ssa_p (cfun))
+	  res = make_ssa_name (type);
+	else
+	  res = create_tmp_reg (type);
+	gimple *stmt = gimple_build_assign (res, build_constructor (type, v));
+	gimple_set_location (stmt, loc);
+	gimple_seq_add_stmt_without_update (seq, stmt);
+	return res;
+      }
+  return build_vector (type, elts);
+}
+
 /* Return true if the result of assignment STMT is known to be non-negative.
    If the return value is based on the assumption that signed overflow is
    undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change

gcc/gimple-fold.h

@@ -127,6 +127,21 @@ gimple_convert_to_ptrofftype (gimple_seq *seq, tree op)
   return gimple_convert_to_ptrofftype (seq, UNKNOWN_LOCATION, op);
 }
 
+extern tree gimple_build_vector_from_val (gimple_seq *, location_t, tree,
+					  tree);
+inline tree
+gimple_build_vector_from_val (gimple_seq *seq, tree type, tree op)
+{
+  return gimple_build_vector_from_val (seq, UNKNOWN_LOCATION, type, op);
+}
+
+extern tree gimple_build_vector (gimple_seq *, location_t, tree, vec<tree>);
+inline tree
+gimple_build_vector (gimple_seq *seq, tree type, vec<tree> elts)
+{
+  return gimple_build_vector (seq, UNKNOWN_LOCATION, type, elts);
+}
+
 extern bool gimple_stmt_nonnegative_warnv_p (gimple *, bool *, int = 0);
 extern bool gimple_stmt_integer_valued_real_p (gimple *, int = 0);