Move gimplify_buildN API local to only remaining user

This moves the legacy gimplify_buildN API to tree-vect-generic.c,
its only user and elides the gimplification step, making it a wrapper
around gimple_build, adjusting tree_vec_extract for this.

I've noticed that vector CTOR expansion doesn't deal with unfolded
{} and thus this makes it more resilent.  I've also adjusted the
match.pd vector CTOR extraction code to make sure it doesn't
produce a CTOR when folding would make it a vector constant.

2021-04-15  Richard Biener  <rguenther@suse.de>

	* tree-cfg.h (gimplify_build1): Remove.
	(gimplify_build2): Likewise.
	(gimplify_build3): Likewise.
	* tree-cfg.c (gimplify_build1): Move to tree-vect-generic.c.
	(gimplify_build2): Likewise.
	(gimplify_build3): Likewise.
	* tree-vect-generic.c (gimplify_build1): Move from tree-cfg.c.
	Modernize.
	(gimplify_build2): Likewise.
	(gimplify_build3): Likewise.
	(tree_vec_extract): Use resimplify with following SSA edges.
	(expand_vector_parallel): Avoid passing NULL size/bitpos
	to tree_vec_extract.
	* expr.c (store_constructor): Deal with zero-element CTORs.
	* match.pd (bit_field_ref <vector CTOR>): Make sure to
	produce vector constants when possible.

gcc/expr.c

@@ -7019,7 +7019,9 @@ store_constructor (tree exp, rtx target, int cleared, poly_int64 size,
 	/* Compute the size of the elements in the CTOR.  It differs
 	   from the size of the vector type elements only when the
 	   CTOR elements are vectors themselves.  */
-	tree val_type = TREE_TYPE (CONSTRUCTOR_ELT (exp, 0)->value);
+	tree val_type = (CONSTRUCTOR_NELTS (exp) != 0
+			 ? TREE_TYPE (CONSTRUCTOR_ELT (exp, 0)->value)
+			 : elttype);
 	if (VECTOR_TYPE_P (val_type))
 	  bitsize = tree_to_uhwi (TYPE_SIZE (val_type));
 	else

gcc/match.pd

@@ -6203,7 +6203,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
       /* We keep an exact subset of the constructor elements.  */
       (if (multiple_p (idx, k, &elt) && multiple_p (n, k, &count))
        (if (CONSTRUCTOR_NELTS (ctor) == 0)
-        { build_constructor (type, NULL); }
+        { build_zero_cst (type); }
 	(if (count == 1)
 	 (if (elt < CONSTRUCTOR_NELTS (ctor))
 	  (view_convert { CONSTRUCTOR_ELT (ctor, elt)->value; })
@@ -6212,15 +6212,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	    ???  Eventually allow this if the CTOR ends up constant or
 	    uniform.  */
 	 (if (single_use (@0))
-	  {
-	    vec<constructor_elt, va_gc> *vals;
-	    vec_alloc (vals, count);
-	    for (unsigned i = 0;
-		 i < count && elt + i < CONSTRUCTOR_NELTS (ctor); ++i)
-	      CONSTRUCTOR_APPEND_ELT (vals, NULL_TREE,
-				      CONSTRUCTOR_ELT (ctor, elt + i)->value);
-	    build_constructor (type, vals);
-	  }))))
+	  (with
+	    {
+	      vec<constructor_elt, va_gc> *vals;
+	      vec_alloc (vals, count);
+	      bool constant_p = true;
+	      tree res;
+	      for (unsigned i = 0;
+		   i < count && elt + i < CONSTRUCTOR_NELTS (ctor); ++i)
+		{
+		  tree e = CONSTRUCTOR_ELT (ctor, elt + i)->value;
+		  CONSTRUCTOR_APPEND_ELT (vals, NULL_TREE, e);
+		  if (!CONSTANT_CLASS_P (e))
+		    constant_p = false;
+		}
+	      res = (constant_p ? build_vector_from_ctor (type, vals)
+		     : build_constructor (type, vals));
+	    }
+	    { res; })))))
       /* The bitfield references a single constructor element.  */
       (if (k.is_constant (&const_k)
 	   && idx + n <= (idx / const_k + 1) * const_k)

gcc/tree-cfg.c

@@ -9198,49 +9198,6 @@ insert_cond_bb (basic_block bb, gimple *stmt, gimple *cond,
   return new_bb;
 }
 
-/* Build a ternary operation and gimplify it.  Emit code before GSI.
-   Return the gimple_val holding the result.  */
-
-tree
-gimplify_build3 (gimple_stmt_iterator *gsi, enum tree_code code,
-		 tree type, tree a, tree b, tree c)
-{
-  tree ret;
-  location_t loc = gimple_location (gsi_stmt (*gsi));
-
-  ret = fold_build3_loc (loc, code, type, a, b, c);
-  return force_gimple_operand_gsi (gsi, ret, true, NULL, true,
-                                   GSI_SAME_STMT);
-}
-
-/* Build a binary operation and gimplify it.  Emit code before GSI.
-   Return the gimple_val holding the result.  */
-
-tree
-gimplify_build2 (gimple_stmt_iterator *gsi, enum tree_code code,
-		 tree type, tree a, tree b)
-{
-  tree ret;
-
-  ret = fold_build2_loc (gimple_location (gsi_stmt (*gsi)), code, type, a, b);
-  return force_gimple_operand_gsi (gsi, ret, true, NULL, true,
-                                   GSI_SAME_STMT);
-}
-
-/* Build a unary operation and gimplify it.  Emit code before GSI.
-   Return the gimple_val holding the result.  */
-
-tree
-gimplify_build1 (gimple_stmt_iterator *gsi, enum tree_code code, tree type,
-		 tree a)
-{
-  tree ret;
-
-  ret = fold_build1_loc (gimple_location (gsi_stmt (*gsi)), code, type, a);
-  return force_gimple_operand_gsi (gsi, ret, true, NULL, true,
-                                   GSI_SAME_STMT);
-}
-
 
 
 /* Given a basic block B which ends with a conditional and has

gcc/tree-cfg.h

@@ -95,12 +95,6 @@ extern bool gimple_purge_dead_eh_edges (basic_block);
 extern bool gimple_purge_all_dead_eh_edges (const_bitmap);
 extern bool gimple_purge_dead_abnormal_call_edges (basic_block);
 extern bool gimple_purge_all_dead_abnormal_call_edges (const_bitmap);
-extern tree gimplify_build3 (gimple_stmt_iterator *, enum tree_code,
-			     tree, tree, tree, tree);
-extern tree gimplify_build2 (gimple_stmt_iterator *, enum tree_code,
-			     tree, tree, tree);
-extern tree gimplify_build1 (gimple_stmt_iterator *, enum tree_code,
-			     tree, tree);
 extern void extract_true_false_edges_from_block (basic_block, edge *, edge *);
 extern tree find_case_label_for_value (const gswitch *switch_stmt, tree val);
 extern edge find_taken_edge_switch_expr (const gswitch *switch_stmt, tree val);

gcc/tree-vect-generic.c

@@ -41,9 +41,54 @@ along with GCC; see the file COPYING3.  If not see
 #include "vec-perm-indices.h"
 #include "insn-config.h"
 #include "tree-ssa-dce.h"
+#include "gimple-fold.h"
+#include "gimple-match.h"
 #include "recog.h"		/* FIXME: for insn_data */
 
 
+/* Build a ternary operation and gimplify it.  Emit code before GSI.
+   Return the gimple_val holding the result.  */
+
+static tree
+gimplify_build3 (gimple_stmt_iterator *gsi, enum tree_code code,
+		 tree type, tree a, tree b, tree c)
+{
+  location_t loc = gimple_location (gsi_stmt (*gsi));
+  gimple_seq stmts = NULL;
+  tree ret = gimple_build (&stmts, loc, code, type, a, b, c);
+  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+  return ret;
+}
+
+/* Build a binary operation and gimplify it.  Emit code before GSI.
+   Return the gimple_val holding the result.  */
+
+static tree
+gimplify_build2 (gimple_stmt_iterator *gsi, enum tree_code code,
+		 tree type, tree a, tree b)
+{
+  location_t loc = gimple_location (gsi_stmt (*gsi));
+  gimple_seq stmts = NULL;
+  tree ret = gimple_build (&stmts, loc, code, type, a, b);
+  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+  return ret;
+}
+
+/* Build a unary operation and gimplify it.  Emit code before GSI.
+   Return the gimple_val holding the result.  */
+
+static tree
+gimplify_build1 (gimple_stmt_iterator *gsi, enum tree_code code, tree type,
+		 tree a)
+{
+  location_t loc = gimple_location (gsi_stmt (*gsi));
+  gimple_seq stmts = NULL;
+  tree ret = gimple_build (&stmts, loc, code, type, a);
+  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+  return ret;
+}
+
+
 static void expand_vector_operations_1 (gimple_stmt_iterator *, bitmap);
 
 /* Return the number of elements in a vector type TYPE that we have
@@ -122,23 +167,25 @@ typedef tree (*elem_op_func) (gimple_stmt_iterator *,
 			      tree, tree, tree, tree, tree, enum tree_code,
 			      tree);
 
+/* Extract the vector element of type TYPE at BITPOS with BITSIZE from T
+   and return it.  */
+
 tree
 tree_vec_extract (gimple_stmt_iterator *gsi, tree type,
 		  tree t, tree bitsize, tree bitpos)
 {
-  if (TREE_CODE (t) == SSA_NAME)
-    {
-      gimple *def_stmt = SSA_NAME_DEF_STMT (t);
-      if (is_gimple_assign (def_stmt)
-	  && (gimple_assign_rhs_code (def_stmt) == VECTOR_CST
-	      || (bitpos
-		  && gimple_assign_rhs_code (def_stmt) == CONSTRUCTOR)))
-	t = gimple_assign_rhs1 (def_stmt);
-    }
-  if (bitpos)
-    return gimplify_build3 (gsi, BIT_FIELD_REF, type, t, bitsize, bitpos);
-  else
-    return gimplify_build1 (gsi, VIEW_CONVERT_EXPR, type, t);
+  /* We're using the resimplify API and maybe_push_res_to_seq to
+     simplify the BIT_FIELD_REF but restrict the simplification to
+     a single stmt while at the same time following SSA edges for
+     simplification with already emitted CTORs.  */
+  gimple_match_op opr;
+  opr.set_op (BIT_FIELD_REF, type, t, bitsize, bitpos);
+  opr.resimplify (NULL, follow_all_ssa_edges);
+  gimple_seq stmts = NULL;
+  tree res = maybe_push_res_to_seq (&opr, &stmts);
+  gcc_assert (res);
+  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
+  return res;
 }
 
 static tree
@@ -327,7 +374,8 @@ expand_vector_parallel (gimple_stmt_iterator *gsi, elem_op_func f, tree type,
       scalar_int_mode mode
 	= int_mode_for_size (tree_to_uhwi (TYPE_SIZE (type)), 0).require ();
       compute_type = lang_hooks.types.type_for_mode (mode, 1);
-      result = f (gsi, compute_type, a, b, NULL_TREE, NULL_TREE, code, type);
+      result = f (gsi, compute_type, a, b, bitsize_zero_node,
+		  TYPE_SIZE (compute_type), code, type);
       warning_at (loc, OPT_Wvector_operation_performance,
 	          "vector operation will be expanded with a "
 		  "single scalar operation");