hooks.c: New file.

* hooks.c: New file.
* hooks.h: New file.
* Makefile.in (HOOKS_H): New.
(TARGET_DEF_H): Added $(HOOKS_H).
(OBJS): Added hooks.o.
(cfgcleanup.o, bb-reorder.o): Added target.h.
(hooks.o): Added dependencies.
* target-def.h (TARGET_CANNOT_MODIFY_JUMPS_P): New, added to...
(TARGET_INITIALIZER): this.
* doc/tm.texi (TARGET_CANNOT_MODIFY_JUMPS_P): Document.
* target.h (struct gcc_target): Added cannot_modify_jumps_p.
* bb-reorder.c: Include target.h.
(reorder_basic_blocks): Skip if cannot modify jumps.
* cfgcleanup.c: Include target.h.
(try_optimize_cfg): Skip merge blocking if cannot modify jumps.

From-SVN: r49627

9 files changed, 245 insertions, 130 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7ce7496..7c2267c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,21 @@
+2002-02-09  Alexandre Oliva  <aoliva@redhat.com>
+
+	* hooks.c: New file.
+	* hooks.h: New file.
+	* Makefile.in (HOOKS_H): New.
+	(TARGET_DEF_H): Added $(HOOKS_H).
+	(OBJS): Added hooks.o.
+	(cfgcleanup.o, bb-reorder.o): Added target.h.
+	(hooks.o): Added dependencies.
+	* target-def.h (TARGET_CANNOT_MODIFY_JUMPS_P): New, added to...
+	(TARGET_INITIALIZER): this.
+	* doc/tm.texi (TARGET_CANNOT_MODIFY_JUMPS_P): Document.
+	* target.h (struct gcc_target): Added cannot_modify_jumps_p.
+	* bb-reorder.c: Include target.h.
+	(reorder_basic_blocks): Skip if cannot modify jumps.
+	* cfgcleanup.c: Include target.h.
+	(try_optimize_cfg): Skip merge blocking if cannot modify jumps.
+
 2002-02-08  Chris Demetriou  <cgd@broadcom.com>
 
         * config/mips/mips.md (casesi_internal, casesi_internal_di):
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index f21ed3d..59f1d3a 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -543,7 +543,8 @@ HCONFIG_H = hconfig.h $(build_xm_file_list)
 CONFIG_H = $(GCONFIG_H) insn-constants.h insn-flags.h
 TCONFIG_H = tconfig.h $(xm_file_list)
 TARGET_H = target.h
-TARGET_DEF_H = target-def.h
+HOOKS_H = hooks.h
+TARGET_DEF_H = target-def.h $(HOOKS_H)
 TM_P_H = tm_p.h $(tm_p_file_list) tm-preds.h
 
 MACHMODE_H = machmode.h machmode.def
@@ -718,7 +719,7 @@ OBJS = alias.o bb-reorder.o bitmap.o builtins.o caller-save.o calls.o	\
  df.o diagnostic.o doloop.o dominance.o dwarf2asm.o dwarf2out.o dwarfout.o \
  emit-rtl.o except.o explow.o expmed.o expr.o final.o flow.o 		\
  fold-const.o function.o gcse.o genrtl.o ggc-common.o global.o graph.o	\
- haifa-sched.o hash.o hashtable.o ifcvt.o insn-attrtab.o insn-emit.o	\
+ haifa-sched.o hash.o hashtable.o hooks.o ifcvt.o insn-attrtab.o insn-emit.o \
  insn-extract.o insn-opinit.o insn-output.o insn-peep.o insn-recog.o	\
  integrate.o intl.o jump.o  langhooks.o lcm.o lists.o local-alloc.o 	\
  loop.o mbchar.o optabs.o params.o predict.o print-rtl.o print-tree.o	\
@@ -1495,7 +1496,7 @@ cfgbuild.o : cfgbuild.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) flags.h insn-config.h \
    function.h except.h $(GGC_H) 
 cfgcleanup.o : cfgcleanup.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TIMEVAR_H)\
    $(BASIC_BLOCK_H) hard-reg-set.h output.h flags.h $(RECOG_H) toplev.h \
-   $(GGC_H) insn-config.h cselib.h $(TM_P_H)
+   $(GGC_H) insn-config.h cselib.h $(TARGET_H) $(TM_P_H)
 cfgloop.o : cfgloop.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) \
    $(BASIC_BLOCK_H) hard-reg-set.h
 dominance.o : dominance.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) hard-reg-set.h \
@@ -1564,8 +1565,8 @@ predict.o: predict.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TREE_H) flags.h \
    insn-config.h $(BASIC_BLOCK_H) $(REGS_H) hard-reg-set.h output.h toplev.h \
    $(RECOG_H) function.h except.h $(EXPR_H) $(TM_P_H) $(PREDICT_H)
 lists.o: lists.c $(CONFIG_H) $(SYSTEM_H) toplev.h $(RTL_H) $(GGC_H)
-bb-reorder.o : bb-reorder.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TREE_H) flags.h \
-   $(BASIC_BLOCK_H) hard-reg-set.h output.h cfglayout.h
+bb-reorder.o : bb-reorder.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TREE_H) \
+   flags.h $(BASIC_BLOCK_H) hard-reg-set.h output.h cfglayout.h $(TARGET_H)
 cfglayout.o : cfglayout.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TREE_H) \
    insn-config.h $(BASIC_BLOCK_H) hard-reg-set.h output.h function.h \
    cfglayout.h
@@ -1579,6 +1580,7 @@ ifcvt.o : ifcvt.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(REGS_H) toplev.h \
 dependence.o : dependence.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TREE_H) \
    $(C_COMMON_H) flags.h varray.h $(EXPR_H)
 params.o : params.c $(CONFIG_H) $(SYSTEM_H) $(PARAMS_H) toplev.h
+hooks.o: hooks.c $(CONFIG_H) $(SYSTEM_H) $(HOOKS_H)
 
 $(out_object_file): $(out_file) $(CONFIG_H) $(TREE_H) $(GGC_H) \
    $(RTL_H) $(REGS_H) hard-reg-set.h real.h insn-config.h conditions.h \
diff --git a/gcc/bb-reorder.c b/gcc/bb-reorder.c
index 97ad142..2578604 100644
--- a/gcc/bb-reorder.c
+++ b/gcc/bb-reorder.c
@@ -1,5 +1,5 @@
 /* Basic block reordering routines for the GNU compiler.
-   Copyright (C) 2000 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2002 Free Software Foundation, Inc.
 
    This file is part of GCC.
 
@@ -89,6 +89,7 @@
 #include "flags.h"
 #include "output.h"
 #include "cfglayout.h"
+#include "target.h"
 
 /* Local function prototypes.  */
 static void make_reorder_chain		PARAMS ((void));
@@ -260,6 +261,9 @@ reorder_basic_blocks ()
   if (n_basic_blocks <= 1)
     return;
 
+  if ((* targetm.cannot_modify_jumps_p) ())
+    return;
+
   cfg_layout_initialize ();
 
   make_reorder_chain ();
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 13c5a8e..d9f9cf2 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -44,6 +44,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "toplev.h"
 #include "cselib.h"
 #include "tm_p.h"
+#include "target.h"
 
 #include "obstack.h"
 
@@ -1531,149 +1532,158 @@ try_optimize_cfg (mode)
   for (i = 0; i < n_basic_blocks; i++)
     update_forwarder_flag (BASIC_BLOCK (i));
 
-  /* Attempt to merge blocks as made possible by edge removal.  If a block
-     has only one successor, and the successor has only one predecessor,
-     they may be combined.  */
-  do
+  if (! (* targetm.cannot_modify_jumps_p) ())
     {
-      changed = false;
-      iterations++;
-
-      if (rtl_dump_file)
-	fprintf (rtl_dump_file, "\n\ntry_optimize_cfg iteration %i\n\n",
-		 iterations);
-
-      for (i = 0; i < n_basic_blocks;)
+      /* Attempt to merge blocks as made possible by edge removal.  If
+	 a block has only one successor, and the successor has only
+	 one predecessor, they may be combined.  */
+      do
 	{
-	  basic_block c, b = BASIC_BLOCK (i);
-	  edge s;
-	  bool changed_here = false;
+	  changed = false;
+	  iterations++;
+
+	  if (rtl_dump_file)
+	    fprintf (rtl_dump_file,
+		     "\n\ntry_optimize_cfg iteration %i\n\n",
+		     iterations);
 
-	  /* Delete trivially dead basic blocks.  */
-	  while (b->pred == NULL)
+	  for (i = 0; i < n_basic_blocks;)
 	    {
-	      c = BASIC_BLOCK (b->index - 1);
-	      if (rtl_dump_file)
-		fprintf (rtl_dump_file, "Deleting block %i.\n", b->index);
+	      basic_block c, b = BASIC_BLOCK (i);
+	      edge s;
+	      bool changed_here = false;
 
-	      flow_delete_block (b);
-	      changed = true;
-	      b = c;
-	    }
+	      /* Delete trivially dead basic blocks.  */
+	      while (b->pred == NULL)
+		{
+		  c = BASIC_BLOCK (b->index - 1);
+		  if (rtl_dump_file)
+		    fprintf (rtl_dump_file, "Deleting block %i.\n",
+			     b->index);
+
+		  flow_delete_block (b);
+		  changed = true;
+		  b = c;
+		}
 
-	  /* Remove code labels no longer used.  Don't do this before
-	     CALL_PLACEHOLDER is removed, as some branches may be hidden
-	     within.  */
-	  if (b->pred->pred_next == NULL
-	      && (b->pred->flags & EDGE_FALLTHRU)
-	      && !(b->pred->flags & EDGE_COMPLEX)
-	      && GET_CODE (b->head) == CODE_LABEL
-	      && (!(mode & CLEANUP_PRE_SIBCALL)
-		  || !tail_recursion_label_p (b->head))
-	      /* If the previous block ends with a branch to this block,
-		 we can't delete the label.  Normally this is a condjump
-		 that is yet to be simplified, but if CASE_DROPS_THRU,
-		 this can be a tablejump with some element going to the
-		 same place as the default (fallthru).  */
-	      && (b->pred->src == ENTRY_BLOCK_PTR
-		  || GET_CODE (b->pred->src->end) != JUMP_INSN
-		  || ! label_is_jump_target_p (b->head, b->pred->src->end)))
-	    {
-	      rtx label = b->head;
+	      /* Remove code labels no longer used.  Don't do this
+		 before CALL_PLACEHOLDER is removed, as some branches
+		 may be hidden within.  */
+	      if (b->pred->pred_next == NULL
+		  && (b->pred->flags & EDGE_FALLTHRU)
+		  && !(b->pred->flags & EDGE_COMPLEX)
+		  && GET_CODE (b->head) == CODE_LABEL
+		  && (!(mode & CLEANUP_PRE_SIBCALL)
+		      || !tail_recursion_label_p (b->head))
+		  /* If the previous block ends with a branch to this
+		     block, we can't delete the label.  Normally this
+		     is a condjump that is yet to be simplified, but
+		     if CASE_DROPS_THRU, this can be a tablejump with
+		     some element going to the same place as the
+		     default (fallthru).  */
+		  && (b->pred->src == ENTRY_BLOCK_PTR
+		      || GET_CODE (b->pred->src->end) != JUMP_INSN
+		      || ! label_is_jump_target_p (b->head,
+						   b->pred->src->end)))
+		{
+		  rtx label = b->head;
 
-	      b->head = NEXT_INSN (b->head);
-	      delete_insn_chain (label, label);
-	      if (rtl_dump_file)
-		fprintf (rtl_dump_file, "Deleted label in block %i.\n",
-			 b->index);
-	    }
+		  b->head = NEXT_INSN (b->head);
+		  delete_insn_chain (label, label);
+		  if (rtl_dump_file)
+		    fprintf (rtl_dump_file, "Deleted label in block %i.\n",
+			     b->index);
+		}
 
-	  /* If we fall through an empty block, we can remove it.  */
-	  if (b->pred->pred_next == NULL
-	      && (b->pred->flags & EDGE_FALLTHRU)
-	      && GET_CODE (b->head) != CODE_LABEL
-	      && FORWARDER_BLOCK_P (b)
-	      /* Note that forwarder_block_p true ensures that there
-		 is a successor for this block.  */
-	      && (b->succ->flags & EDGE_FALLTHRU)
-	      && n_basic_blocks > 1)
-	    {
-	      if (rtl_dump_file)
-		fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
-			 b->index);
+	      /* If we fall through an empty block, we can remove it.  */
+	      if (b->pred->pred_next == NULL
+		  && (b->pred->flags & EDGE_FALLTHRU)
+		  && GET_CODE (b->head) != CODE_LABEL
+		  && FORWARDER_BLOCK_P (b)
+		  /* Note that forwarder_block_p true ensures that
+		     there is a successor for this block.  */
+		  && (b->succ->flags & EDGE_FALLTHRU)
+		  && n_basic_blocks > 1)
+		{
+		  if (rtl_dump_file)
+		    fprintf (rtl_dump_file,
+			     "Deleting fallthru block %i.\n",
+			     b->index);
+
+		  c = BASIC_BLOCK (b->index ? b->index - 1 : 1);
+		  redirect_edge_succ_nodup (b->pred, b->succ->dest);
+		  flow_delete_block (b);
+		  changed = true;
+		  b = c;
+		}
 
-	      c = BASIC_BLOCK (b->index ? b->index - 1 : 1);
-	      redirect_edge_succ_nodup (b->pred, b->succ->dest);
-	      flow_delete_block (b);
-	      changed = true;
-	      b = c;
-	    }
+	      /* Merge blocks.  Loop because chains of blocks might be
+		 combineable.  */
+	      while ((s = b->succ) != NULL
+		     && s->succ_next == NULL
+		     && !(s->flags & EDGE_COMPLEX)
+		     && (c = s->dest) != EXIT_BLOCK_PTR
+		     && c->pred->pred_next == NULL
+		     /* If the jump insn has side effects,
+			we can't kill the edge.  */
+		     && (GET_CODE (b->end) != JUMP_INSN
+			 || onlyjump_p (b->end))
+		     && merge_blocks (s, b, c, mode))
+		changed_here = true;
+
+	      /* Simplify branch over branch.  */
+	      if ((mode & CLEANUP_EXPENSIVE) && try_simplify_condjump (b))
+		{
+		  BB_SET_FLAG (b, BB_UPDATE_LIFE);
+		  changed_here = true;
+		}
 
-	  /* Merge blocks.  Loop because chains of blocks might be
-	     combineable.  */
-	  while ((s = b->succ) != NULL
-		 && s->succ_next == NULL
-	         && !(s->flags & EDGE_COMPLEX)
-		 && (c = s->dest) != EXIT_BLOCK_PTR
-		 && c->pred->pred_next == NULL
-		 /* If the jump insn has side effects,
-		    we can't kill the edge.  */
-		 && (GET_CODE (b->end) != JUMP_INSN
-		     || onlyjump_p (b->end))
-		 && merge_blocks (s, b, c, mode))
-	    changed_here = true;
-
-	  /* Simplify branch over branch.  */
-	  if ((mode & CLEANUP_EXPENSIVE) && try_simplify_condjump (b))
-	    {
-	      BB_SET_FLAG (b, BB_UPDATE_LIFE);
-	      changed_here = true;
-	    }
+	      /* If B has a single outgoing edge, but uses a
+		 non-trivial jump instruction without side-effects, we
+		 can either delete the jump entirely, or replace it
+		 with a simple unconditional jump.  Use
+		 redirect_edge_and_branch to do the dirty work.  */
+	      if (b->succ
+		  && ! b->succ->succ_next
+		  && b->succ->dest != EXIT_BLOCK_PTR
+		  && onlyjump_p (b->end)
+		  && redirect_edge_and_branch (b->succ, b->succ->dest))
+		{
+		  BB_SET_FLAG (b, BB_UPDATE_LIFE);
+		  update_forwarder_flag (b);
+		  changed_here = true;
+		}
 
-	  /* If B has a single outgoing edge, but uses a non-trivial jump
-	     instruction without side-effects, we can either delete the
-	     jump entirely, or replace it with a simple unconditional jump.
-	     Use redirect_edge_and_branch to do the dirty work.  */
-	  if (b->succ
-	      && ! b->succ->succ_next
-	      && b->succ->dest != EXIT_BLOCK_PTR
-	      && onlyjump_p (b->end)
-	      && redirect_edge_and_branch (b->succ, b->succ->dest))
-	    {
-	      BB_SET_FLAG (b, BB_UPDATE_LIFE);
-	      update_forwarder_flag (b);
-	      changed_here = true;
-	    }
+	      /* Simplify branch to branch.  */
+	      if (try_forward_edges (mode, b))
+		changed_here = true;
 
-	  /* Simplify branch to branch.  */
-	  if (try_forward_edges (mode, b))
-	    changed_here = true;
+	      /* Look for shared code between blocks.  */
+	      if ((mode & CLEANUP_CROSSJUMP)
+		  && try_crossjump_bb (mode, b))
+		changed_here = true;
 
-	  /* Look for shared code between blocks.  */
-	  if ((mode & CLEANUP_CROSSJUMP)
-	      && try_crossjump_bb (mode, b))
-	    changed_here = true;
+	      /* Don't get confused by the index shift caused by
+		 deleting blocks.  */
+	      if (!changed_here)
+		i = b->index + 1;
+	      else
+		changed = true;
+	    }
 
-	  /* Don't get confused by the index shift caused by deleting
-	     blocks.  */
-	  if (!changed_here)
-	    i = b->index + 1;
-	  else
+	  if ((mode & CLEANUP_CROSSJUMP)
+	      && try_crossjump_bb (mode, EXIT_BLOCK_PTR))
 	    changed = true;
-	}
-
-      if ((mode & CLEANUP_CROSSJUMP)
-	  && try_crossjump_bb (mode, EXIT_BLOCK_PTR))
-	changed = true;
 
 #ifdef ENABLE_CHECKING
-      if (changed)
-	verify_flow_info ();
+	  if (changed)
+	    verify_flow_info ();
 #endif
 
-      changed_overall |= changed;
+	  changed_overall |= changed;
+	}
+      while (changed);
     }
-  while (changed);
 
   if (mode & CLEANUP_CROSSJUMP)
     remove_fake_edges ();
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index ff25523..3cb5c68 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -8616,3 +8616,18 @@ object files that are not referenced from @code{main} and uses export
 lists.
 
 @end table
+
+@deftypefn {Target Hook} bool TARGET_CANNOT_MODIFY_JUMPS_P (void)
+This target hook returns @code{true} past the point in which new jump
+instructions could be created.  On machines that require a register for
+every jump such as the SHmedia ISA of SH5, this point would typically be
+reload, so this target hook should be defined to a function such as:
+
+@smallexample
+static bool
+cannot_modify_jumps_past_reload_p ()
+@{
+  return (reload_completed || reload_in_progress);
+@}
+@end smallexample
+@end deftypefn
diff --git a/gcc/hooks.c b/gcc/hooks.c
new file mode 100644
index 0000000..387f4db
--- /dev/null
+++ b/gcc/hooks.c
@@ -0,0 +1,34 @@
+/* General-purpose hooks.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+
+This program is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+ In other words, you are welcome to use, share and improve this program.
+ You are forbidden to forbid anyone else to use, share and improve
+ what you give them.   Help stamp out software-hoarding!  */
+
+/* This file contains generic hooks that can be used as defaults for
+   target or language-dependent hook initializers.  */
+
+#include "config.h"
+#include "system.h"
+#include "hooks.h"
+
+/* Generic hook that takes no arguments and returns false.  */
+bool
+hook_void_bool_false ()
+{
+  return false;
+}
diff --git a/gcc/hooks.h b/gcc/hooks.h
new file mode 100644
index 0000000..7a8daa5
--- /dev/null
+++ b/gcc/hooks.h
@@ -0,0 +1,22 @@
+/* General-purpose hooks.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+
+This program is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+ In other words, you are welcome to use, share and improve this program.
+ You are forbidden to forbid anyone else to use, share and improve
+ what you give them.   Help stamp out software-hoarding!  */
+
+bool hook_void_bool_false PARAMS ((void));
diff --git a/gcc/target-def.h b/gcc/target-def.h
index bc93b50..71987f5 100644
--- a/gcc/target-def.h
+++ b/gcc/target-def.h
@@ -175,6 +175,9 @@ Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #define TARGET_SECTION_TYPE_FLAGS default_section_type_flags
 #endif
 
+/* In hook.c.  */
+#define TARGET_CANNOT_MODIFY_JUMPS_P hook_void_bool_false
+
 /* The whole shebang.  */
 #define TARGET_INITIALIZER			\
 {						\
@@ -192,5 +195,8 @@ Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   TARGET_EXPAND_BUILTIN,			\
   TARGET_SECTION_TYPE_FLAGS,			\
   TARGET_HAVE_NAMED_SECTIONS,			\
-  TARGET_HAVE_CTORS_DTORS			\
+  TARGET_HAVE_CTORS_DTORS,			\
+  TARGET_CANNOT_MODIFY_JUMPS_P			\
 }
+
+#include "hooks.h"
diff --git a/gcc/target.h b/gcc/target.h
index 38ce359..5ee9aa6 100644
--- a/gcc/target.h
+++ b/gcc/target.h
@@ -184,6 +184,10 @@ struct gcc_target
   /* True if "native" constructors and destructors are supported,
      false if we're using collect2 for the job.  */
   bool have_ctors_dtors;
+
+  /* True if new jumps cannot be created, to replace existing ones or
+     not, at the current point in the compilation.  */
+  bool (* cannot_modify_jumps_p) PARAMS ((void));
 };
 
 extern struct gcc_target targetm;