inliner: Remove unused transform_lang_insert_block hook

This struct copy_body_data's hook is always NULL since merge
of the tuples branch, before that it has been shortly used by the C++
FE during ctor/dtor cloning to chain the remapped blocks, but only
very shortly, before transform_lang_insert_block was a bool and
the call to insert_block was done through a langhook.
I'd say that for something that hasn't been used since 4.4 there is
zero chance we'll want to use it again in the near future.

2021-11-23  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* tree-inline.h (struct copy_body_data): Remove
	transform_lang_insert_block member.
	* tree-inline.c (remap_block): Don't call
	id->transform_lang_insert_block.
	(optimize_inline_calls, copy_gimple_seq_and_replace_locals,
	tree_function_versioning, maybe_inline_call_in_expr,
	copy_fn): Don't initialize id.transform_lang_insert_block.
	* gimplify.c (gimplify_omp_loop): Likewise.
gcc/c/
	* c-typeck.c (c_clone_omp_udr): Don't initialize
	id.transform_lang_insert_block.
gcc/cp/
	* semantics.c (clone_omp_udr): Don't initialize
	id.transform_lang_insert_block.
	* optimize.c (clone_body): Likewise.

gcc/c/c-typeck.c

@@ -13848,7 +13848,6 @@ c_clone_omp_udr (tree stmt, tree omp_decl1, tree omp_decl2,
   id.transform_call_graph_edges = CB_CGE_DUPLICATE;
   id.transform_new_cfg = true;
   id.transform_return_to_modify = false;
-  id.transform_lang_insert_block = NULL;
   id.eh_lp_nr = 0;
   walk_tree (&stmt, copy_tree_body_r, &id, NULL);
   return stmt;

gcc/cp/optimize.c

@@ -103,7 +103,6 @@ clone_body (tree clone, tree fn, void *arg_map)
   id.transform_call_graph_edges = CB_CGE_DUPLICATE;
   id.transform_new_cfg = true;
   id.transform_return_to_modify = false;
-  id.transform_lang_insert_block = NULL;
 
   /* We're not inside any EH region.  */
   id.eh_lp_nr = 0;

gcc/cp/semantics.c

@@ -6066,7 +6066,6 @@ clone_omp_udr (tree stmt, tree omp_decl1, tree omp_decl2,
   id.transform_call_graph_edges = CB_CGE_DUPLICATE;
   id.transform_new_cfg = true;
   id.transform_return_to_modify = false;
-  id.transform_lang_insert_block = NULL;
   id.eh_lp_nr = 0;
   walk_tree (&stmt, copy_tree_body_r, &id, NULL);
   return stmt;

gcc/gimplify.c

@@ -13413,7 +13413,6 @@ gimplify_omp_loop (tree *expr_p, gimple_seq *pre_p)
 		id.transform_call_graph_edges = CB_CGE_DUPLICATE;
 		id.transform_new_cfg = true;
 		id.transform_return_to_modify = false;
-		id.transform_lang_insert_block = NULL;
 		id.eh_lp_nr = 0;
 		walk_tree (&OMP_CLAUSE_REDUCTION_INIT (*pc), copy_tree_body_r,
 			   &id, NULL);

gcc/tree-inline.c

@@ -823,9 +823,6 @@ remap_block (tree *block, copy_body_data *id)
   					&BLOCK_NONLOCALIZED_VARS (new_block),
 					id);
 
-  if (id->transform_lang_insert_block)
-    id->transform_lang_insert_block (new_block);
-
   /* Remember the remapped block.  */
   insert_decl_map (id, old_block, new_block);
 }
@@ -5473,7 +5470,6 @@ optimize_inline_calls (tree fn)
   id.transform_new_cfg = false;
   id.transform_return_to_modify = true;
   id.transform_parameter = true;
-  id.transform_lang_insert_block = NULL;
   id.statements_to_fold = new hash_set<gimple *>;
 
   push_gimplify_context ();
@@ -5857,7 +5853,6 @@ copy_gimple_seq_and_replace_locals (gimple_seq seq)
   id.transform_new_cfg = false;
   id.transform_return_to_modify = false;
   id.transform_parameter = false;
-  id.transform_lang_insert_block = NULL;
 
   /* Walk the tree once to find local labels.  */
   memset (&wi, 0, sizeof (wi));
@@ -6252,7 +6247,6 @@ tree_function_versioning (tree old_decl, tree new_decl,
   id.transform_new_cfg = true;
   id.transform_return_to_modify = false;
   id.transform_parameter = false;
-  id.transform_lang_insert_block = NULL;
 
   old_entry_block = ENTRY_BLOCK_PTR_FOR_FN
     (DECL_STRUCT_FUNCTION (old_decl));
@@ -6541,7 +6535,6 @@ maybe_inline_call_in_expr (tree exp)
       id.transform_new_cfg = false;
       id.transform_return_to_modify = true;
       id.transform_parameter = true;
-      id.transform_lang_insert_block = NULL;
 
       /* Make sure not to unshare trees behind the front-end's back
 	 since front-end specific mechanisms may rely on sharing.  */
@@ -6613,7 +6606,6 @@ copy_fn (tree fn, tree& parms, tree& result)
   id.transform_new_cfg = false;
   id.transform_return_to_modify = false;
   id.transform_parameter = true;
-  id.transform_lang_insert_block = NULL;
 
   /* Make sure not to unshare trees behind the front-end's back
      since front-end specific mechanisms may rely on sharing.  */

gcc/tree-inline.h

@@ -133,9 +133,6 @@ struct copy_body_data
      and only in that case will actually remap the type.  */
   bool dont_remap_vla_if_no_change;
 
-  /* A function to be called when duplicating BLOCK nodes.  */
-  void (*transform_lang_insert_block) (tree);
-
   /* Statements that might be possibly folded.  */
   hash_set<gimple *> *statements_to_fold;