RFA: Use target-insns.def for casesi and tablejump

[Richard Sandiford <richard dot sandiford at arm dot com>]

This patch uses target-insns.def to define casesi and tablejump.
It's the first point in the series at which we need access to the
instruction code, so the patch adds that to targetm as well.

Bootstrapped & regression-tested on x86_64-linux-gnu and aarch64-linux-gnu.
Also tested via config-list.mk.  OK to install?

Thanks,
Richard


gcc/
	* target.def: Add code_for_* hooks.
	* gentarget-def.c (def_target_insn): Add TARGET_CODE_FOR_* macros.
	* defaults.h (HAVE_tablejump, gen_tablejump): Delete.
	* target-insns.def (casesi, tablejump): New targetm instruction
	patterns.
	* expr.c (try_casesi): Use them instead of HAVE_*/gen_* interface.
	(do_tablejump): Likewise.
	* stmt.c (expand_switch_as_decision_tree_p): Likewise.
	(expand_sjlj_dispatch_table): Likewise.
	* targhooks.c (default_case_values_threshold): Likewise.

Index: gcc/target.def
===================================================================
--- gcc/target.def	2015-06-30 21:57:42.678281095 +0100
+++ gcc/target.def	2015-06-30 21:57:42.674281140 +0100
@@ -5877,6 +5877,11 @@ HOOK_VECTOR_END (mode_switching)
 #include "target-insns.def"
 #undef DEF_TARGET_INSN
 
+#define DEF_TARGET_INSN(NAME, PROTO) \
+  DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
+#include "target-insns.def"
+#undef DEF_TARGET_INSN
+
 /* Close the 'struct gcc_target' definition.  */
 HOOK_VECTOR_END (C90_EMPTY_HACK)
 
Index: gcc/gentarget-def.c
===================================================================
--- gcc/gentarget-def.c	2015-06-30 21:57:42.678281095 +0100
+++ gcc/gentarget-def.c	2015-06-30 21:57:42.674281140 +0100
@@ -189,6 +189,13 @@ def_target_insn (const char *name, const
     printf ("invalid_%s\n", suffix);
   else
     printf ("target_gen_%s\n", name);
+
+  printf ("#undef TARGET_CODE_FOR_%s\n", upper_name);
+  printf ("#define TARGET_CODE_FOR_%s ", upper_name);
+  if (truth == 0)
+    printf ("CODE_FOR_nothing\n");
+  else
+    printf ("CODE_FOR_%s\n", name);
 }
 
 int
Index: gcc/defaults.h
===================================================================
--- gcc/defaults.h	2015-06-30 21:57:42.678281095 +0100
+++ gcc/defaults.h	2015-06-30 21:57:42.670281186 +0100
@@ -1426,16 +1426,6 @@ #define STACK_CHECK_MAX_VAR_SIZE (STACK_
 #define TARGET_VTABLE_USES_DESCRIPTORS 0
 #endif
 
-#ifndef HAVE_tablejump
-#define HAVE_tablejump 0
-static inline rtx
-gen_tablejump (rtx, rtx)
-{
-  gcc_unreachable ();
-  return NULL;
-}
-#endif
-
 #endif /* GCC_INSN_FLAGS_H  */
 
 #endif  /* ! GCC_DEFAULTS_H */
Index: gcc/target-insns.def
===================================================================
--- gcc/target-insns.def	2015-06-30 21:57:42.678281095 +0100
+++ gcc/target-insns.def	2015-06-30 21:57:42.674281140 +0100
@@ -31,6 +31,7 @@
 
    Instructions should be documented in md.texi rather than here.  */
 DEF_TARGET_INSN (canonicalize_funcptr_for_compare, (rtx x0, rtx x1))
+DEF_TARGET_INSN (casesi, (rtx x0, rtx x1, rtx x2, rtx x3, rtx x4))
 DEF_TARGET_INSN (epilogue, (void))
 DEF_TARGET_INSN (jump, (rtx x0))
 DEF_TARGET_INSN (load_multiple, (rtx x0, rtx x1, rtx x2))
@@ -42,3 +43,4 @@ DEF_TARGET_INSN (return, (void))
 DEF_TARGET_INSN (sibcall_epilogue, (void))
 DEF_TARGET_INSN (simple_return, (void))
 DEF_TARGET_INSN (store_multiple, (rtx x0, rtx x1, rtx x2))
+DEF_TARGET_INSN (tablejump, (rtx x0, rtx x1))
Index: gcc/expr.c
===================================================================
--- gcc/expr.c	2015-06-30 21:57:42.678281095 +0100
+++ gcc/expr.c	2015-06-30 21:57:42.670281186 +0100
@@ -11058,14 +11058,6 @@ do_store_flag (sepops ops, rtx target, m
 				 && !TYPE_UNSIGNED (ops->type)) ? -1 : 1);
 }
 
-
-/* Stubs in case we haven't got a casesi insn.  */
-#ifndef HAVE_casesi
-# define HAVE_casesi 0
-# define gen_casesi(a, b, c, d, e) (0)
-# define CODE_FOR_casesi CODE_FOR_nothing
-#endif
-
 /* Attempt to generate a casesi instruction.  Returns 1 if successful,
    0 otherwise (i.e. if there is no casesi instruction).
 
@@ -11080,7 +11072,7 @@ try_casesi (tree index_type, tree index_
   machine_mode index_mode = SImode;
   rtx op1, op2, index;
 
-  if (! HAVE_casesi)
+  if (! targetm.have_casesi ())
     return 0;
 
   /* Convert the index to SImode.  */
@@ -11124,7 +11116,7 @@ try_casesi (tree index_type, tree index_
   create_fixed_operand (&ops[4], (default_label
 				  ? default_label
 				  : fallback_label));
-  expand_jump_insn (CODE_FOR_casesi, 5, ops);
+  expand_jump_insn (targetm.code_for_casesi, 5, ops);
   return 1;
 }
 
@@ -11197,7 +11189,7 @@ do_tablejump (rtx index, machine_mode mo
   vector = gen_const_mem (CASE_VECTOR_MODE, index);
   convert_move (temp, vector, 0);
 
-  emit_jump_insn (gen_tablejump (temp, table_label));
+  emit_jump_insn (targetm.gen_tablejump (temp, table_label));
 
   /* If we are generating PIC code or if the table is PC-relative, the
      table and JUMP_INSN must be adjacent, so don't output a BARRIER.  */
@@ -11211,7 +11203,7 @@ try_tablejump (tree index_type, tree ind
 {
   rtx index;
 
-  if (! HAVE_tablejump)
+  if (! targetm.have_tablejump ())
     return 0;
 
   index_expr = fold_build2 (MINUS_EXPR, index_type,
Index: gcc/stmt.c
===================================================================
--- gcc/stmt.c	2015-06-30 21:57:42.678281095 +0100
+++ gcc/stmt.c	2015-06-30 21:57:42.670281186 +0100
@@ -780,10 +780,6 @@ dump_case_nodes (FILE *f, struct case_no
   dump_case_nodes (f, root->right, indent_step, indent_level);
 }
 
-#ifndef HAVE_casesi
-#define HAVE_casesi 0
-#endif
-
 /* Return the smallest number of different values for which it is best to use a
    jump-table instead of a tree of conditional branches.  */
 
@@ -812,7 +808,7 @@ expand_switch_as_decision_tree_p (tree r
 
   /* If neither casesi or tablejump is available, or flag_jump_tables
      over-ruled us, we really have no choice.  */
-  if (!HAVE_casesi && !HAVE_tablejump)
+  if (!targetm.have_casesi () && !targetm.have_tablejump ())
     return true;
   if (!flag_jump_tables)
     return true;
@@ -1291,7 +1287,7 @@ expand_sjlj_dispatch_table (rtx dispatch
      of expanding as a decision tree or dispatch table vs. the "new
      way" with decrement chain or dispatch table.  */
   if (dispatch_table.length () <= 5
-      || (!HAVE_casesi && !HAVE_tablejump)
+      || (!targetm.have_casesi () && !targetm.have_tablejump ())
       || !flag_jump_tables)
     {
       /* Expand the dispatch as a decrement chain:
Index: gcc/targhooks.c
===================================================================
--- gcc/targhooks.c	2015-06-30 21:57:42.678281095 +0100
+++ gcc/targhooks.c	2015-06-30 21:57:42.674281140 +0100
@@ -1339,10 +1339,6 @@ default_target_can_inline_p (tree caller
   return ret;
 }
 
-#ifndef HAVE_casesi
-# define HAVE_casesi 0
-#endif
-
 /* If the machine does not have a case insn that compares the bounds,
    this means extra overhead for dispatch tables, which raises the
    threshold for using them.  */
@@ -1350,7 +1346,7 @@ default_target_can_inline_p (tree caller
 unsigned int
 default_case_values_threshold (void)
 {
-  return (HAVE_casesi ? 4 : 5);
+  return (targetm.have_casesi () ? 4 : 5);
 }
 
 bool