Makefile.in (flow.o): Depend on TREE_H.

	* Makefile.in (flow.o): Depend on TREE_H.
	* basic-block.h (REG_SET_EQUAL_P): New.
	(XOR_REG_SET): New.
	(n_edges): Declare.
	(free_regset_vector): Remove declaration.
	(flow_delete_insn_chain): Declare.
	(enum update_life_extent): New.
	(update_life_info, count_or_remove_death_notes): Declare.
	* combine.c (distribute_notes) [REG_DEAD]: Stop search at bb->head.
	Verify register live at bb->global_live_at_start before adding USE.
	* flow.c (HAVE_epilogue, HAVE_prologue): Provide default.
	(CLEAN_ALLOCA): New.
	(n_edges): New.
	(PROP_*): New flags.
	(find_basic_blocks_1): Use alloc_EXPR_LIST.
	(clear_edges): Zero n_edges.
	(make_edge): Increment n_edges.
	(split_edge): Don't allocate bb->local_set.  Increment n_edges.
	(flow_delete_insn_chain): Export.
	(delete_block): Decrement n_edges.
	(merge_blocks_nomove): Likewise.
	(life_analysis): Give life_analysis_1 PROP flags.
	(verify_wide_reg_1, verify_wide_reg): New.
	(verify_local_live_at_start): New.
	(update_life_info): Rewrite to call into propogate_block.
	(mark_reg): New.
	(mark_regs_live_at_end): After reload, if epilogue as rtl,
	always mark stack pointer.  Conditionally mark PIC register.
	After reload, mark call-saved registers, return regsiters.
	(life_analysis_1): Accept PROP flags not remove_dead_code.
	Call mark_regs_live_at_end before zeroing regs_ever_live.
	Use calculate_global_regs_live.  Copy global_live_at_end before
	calling final propagate_block.  Zero reg_next_use on exit.
	(calculate_global_regs_live): New.
	(allocate_bb_life_data): Don't allocate bb->local_set.
	(init_regset_vector, free_regset_vector): Remove.
	(propagate_block): Accept FLAGS not FINAL or REMOVE_DEAD_CODE.
	Test flags before every operation.  Warn if prologue/epilogue insn
	would have been deleted.
	(mark_set_regs, mark_set_1): Accept and use FLAGS.
	Use alloc_EXPR_LIST.
	(mark_used_regs): Accept and use FLAGS, not FINAL.
	Remove special handling for RETURN.
	(try_pre_increment): Use alloc_EXPR_LIST.
	(dump_flow_info): Dump n_edges.
	(unlink_insn_chain, split_hard_reg_notes): Remove.
	(maybe_add_dead_note, maybe_add_dead_note_use): Remove.
	(find_insn_with_note, new_insn_dead_notes): Remove.
	(update_n_sets, sets_reg_or_subreg_1, sets_reg_or_subreg): Remove.
	(maybe_remove_dead_notes, prepend_reg_notes): Remove.
	(replace_insns): Remove.
	(count_or_remove_death_notes): New.
	(verify_flow_info): Abort on error after all checks.
	(remove_edge): Decrement n_edges.
	(remove_fake_edges): Tweek format.
	* haifa-sched.c (schedule_insns): Use split_all_insns.
	* output.h (update_life_info): Remove declaration.
	* recog.c (split_all_insns): From the corpse of split_block_insns,
	do the whole function block by block.  Use update_life_info.
	(recog_last_allowed_insn): New.
	(recog_next_insn): Mind it.
	(peephole2_optimize): Set it.  Walk backwards through blocks.
	Use update_life_info.
	* rtl.h (update_flow_info, replace_insns): Remove declarations.
	(split_all_insns): Declare.
	* toplev.c (rest_of_compilation): Thread prologue before flow2.
	Use split_all_insns.

	* i386.md (or -1 peep2s): Disable.

From-SVN: r29877

gcc/ChangeLog

+Sat Oct  9 12:18:16 1999  Richard Henderson  <rth@cygnus.com>
+
+	* Makefile.in (flow.o): Depend on TREE_H.
+	* basic-block.h (REG_SET_EQUAL_P): New.
+	(XOR_REG_SET): New.
+	(n_edges): Declare.
+	(free_regset_vector): Remove declaration.
+	(flow_delete_insn_chain): Declare.
+	(enum update_life_extent): New.
+	(update_life_info, count_or_remove_death_notes): Declare.
+	* combine.c (distribute_notes) [REG_DEAD]: Stop search at bb->head.
+	Verify register live at bb->global_live_at_start before adding USE.
+	* flow.c (HAVE_epilogue, HAVE_prologue): Provide default.
+	(CLEAN_ALLOCA): New.
+	(n_edges): New.	
+	(PROP_*): New flags.
+	(find_basic_blocks_1): Use alloc_EXPR_LIST.
+	(clear_edges): Zero n_edges.
+	(make_edge): Increment n_edges.
+	(split_edge): Don't allocate bb->local_set.  Increment n_edges.
+	(flow_delete_insn_chain): Export.
+	(delete_block): Decrement n_edges.
+	(merge_blocks_nomove): Likewise.
+	(life_analysis): Give life_analysis_1 PROP flags.
+	(verify_wide_reg_1, verify_wide_reg): New.
+	(verify_local_live_at_start): New.
+	(update_life_info): Rewrite to call into propogate_block.
+	(mark_reg): New.
+	(mark_regs_live_at_end): After reload, if epilogue as rtl, 
+	always mark stack pointer.  Conditionally mark PIC register.
+	After reload, mark call-saved registers, return regsiters.
+	(life_analysis_1): Accept PROP flags not remove_dead_code.
+	Call mark_regs_live_at_end before zeroing regs_ever_live.
+	Use calculate_global_regs_live.  Copy global_live_at_end before
+	calling final propagate_block.  Zero reg_next_use on exit.
+	(calculate_global_regs_live): New.
+	(allocate_bb_life_data): Don't allocate bb->local_set.
+	(init_regset_vector, free_regset_vector): Remove.
+	(propagate_block): Accept FLAGS not FINAL or REMOVE_DEAD_CODE.
+	Test flags before every operation.  Warn if prologue/epilogue insn
+	would have been deleted.
+	(mark_set_regs, mark_set_1): Accept and use FLAGS. 
+	Use alloc_EXPR_LIST.
+	(mark_used_regs): Accept and use FLAGS, not FINAL.
+	Remove special handling for RETURN.
+	(try_pre_increment): Use alloc_EXPR_LIST.
+	(dump_flow_info): Dump n_edges.
+	(unlink_insn_chain, split_hard_reg_notes): Remove.
+	(maybe_add_dead_note, maybe_add_dead_note_use): Remove.
+	(find_insn_with_note, new_insn_dead_notes): Remove.
+	(update_n_sets, sets_reg_or_subreg_1, sets_reg_or_subreg): Remove.
+	(maybe_remove_dead_notes, prepend_reg_notes): Remove.
+	(replace_insns): Remove.
+	(count_or_remove_death_notes): New.
+	(verify_flow_info): Abort on error after all checks.
+	(remove_edge): Decrement n_edges.
+	(remove_fake_edges): Tweek format.
+	* haifa-sched.c (schedule_insns): Use split_all_insns.
+	* output.h (update_life_info): Remove declaration.
+	* recog.c (split_all_insns): From the corpse of split_block_insns,
+	do the whole function block by block.  Use update_life_info.
+	(recog_last_allowed_insn): New.
+	(recog_next_insn): Mind it.
+	(peephole2_optimize): Set it.  Walk backwards through blocks.
+	Use update_life_info.
+	* rtl.h (update_flow_info, replace_insns): Remove declarations.
+	(split_all_insns): Declare.
+	* toplev.c (rest_of_compilation): Thread prologue before flow2.
+	Use split_all_insns.
+
+	* i386.md (or -1 peep2s): Disable.
+
 Fri Oct  8 17:49:08 1999  Richard Henderson  <rth@cygnus.com>
 
 	* config/mips/mips.md (movstrsi+[123]) : Combine these into

gcc/Makefile.in

@@ -1549,7 +1549,7 @@ loop.o : loop.c $(CONFIG_H) system.h $(RTL_H) flags.h loop.h insn-config.h \
    function.h toplev.h varray.h
 unroll.o : unroll.c $(CONFIG_H) system.h $(RTL_H) insn-config.h function.h \
    integrate.h $(REGS_H) $(RECOG_H) flags.h $(EXPR_H) loop.h toplev.h varray.h
-flow.o : flow.c $(CONFIG_H) system.h $(RTL_H) flags.h insn-config.h \
+flow.o : flow.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 \
    insn-flags.h function.h
 combine.o : combine.c $(CONFIG_H) system.h $(RTL_H) flags.h function.h \

gcc/basic-block.h

@@ -31,6 +31,9 @@ typedef bitmap regset;		/* Head of register set linked list.  */
 /* Copy a register set to another register set.  */
 #define COPY_REG_SET(TO, FROM) bitmap_copy (TO, FROM)
 
+/* Compare two register sets.  */
+#define REG_SET_EQUAL_P(A, B) bitmap_equal_p (A, B)
+
 /* `and' a register set with a second register set.  */
 #define AND_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_AND)
 
@@ -41,6 +44,9 @@ typedef bitmap regset;		/* Head of register set linked list.  */
 /* Inclusive or a register set with a second register set.  */
 #define IOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_IOR)
 
+/* Exclusive or a register set with a second register set.  */
+#define XOR_REG_SET(TO, FROM) bitmap_operation (TO, TO, FROM, BITMAP_XOR)
+
 /* Or into TO the register set FROM1 `and'ed with the complement of FROM2.  */
 #define IOR_AND_COMPL_REG_SET(TO, FROM1, FROM2) \
   bitmap_ior_and_compl (TO, FROM1, FROM2)
@@ -153,6 +159,10 @@ typedef struct basic_block_def {
 
 extern int n_basic_blocks;
 
+/* Number of edges in the current function.  */
+
+extern int n_edges;
+
 /* Index by basic block number, get basic block struct info.  */
 
 extern varray_type basic_block_info;
@@ -229,9 +239,6 @@ extern struct basic_block_def entry_exit_blocks[2];
 #define ENTRY_BLOCK_PTR	(&entry_exit_blocks[0])
 #define EXIT_BLOCK_PTR	(&entry_exit_blocks[1])
 
-/* from flow.c */
-extern void free_regset_vector		PROTO ((regset *, int nelts));
-
 extern varray_type basic_block_for_insn;
 #define BLOCK_FOR_INSN(INSN)  VARRAY_BB (basic_block_for_insn, INSN_UID (INSN))
 #define BLOCK_NUM(INSN)	      (BLOCK_FOR_INSN (INSN)->index + 0)
@@ -249,6 +256,7 @@ extern void insert_insn_on_edge		PROTO ((rtx, edge));
 extern void commit_edge_insertions	PROTO ((void));
 extern void remove_fake_edges		PROTO ((void));
 extern void add_noreturn_fake_exit_edges	PROTO ((void));
+extern void flow_delete_insn_chain	PROTO((rtx, rtx));
 
 /* This structure maintains an edge list vector.  */
 struct edge_list 
@@ -291,6 +299,15 @@ extern void compute_dominators		PROTO ((sbitmap *, sbitmap *,
 extern void compute_flow_dominators	PROTO ((sbitmap *, sbitmap *));
 extern void compute_immediate_dominators	PROTO ((int *, sbitmap *));
 
+enum update_life_extent
+{
+  UPDATE_LIFE_GLOBAL = 0,
+  UPDATE_LIFE_LOCAL = 1
+};
+
+extern void update_life_info	PROTO ((sbitmap, enum update_life_extent));
+extern int count_or_remove_death_notes	PROTO ((sbitmap, int));
+
 /* In lcm.c */
 extern void pre_lcm 			PROTO ((int, int, int_list_ptr *,
 						int_list_ptr *,

gcc/combine.c

@@ -11721,11 +11721,17 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 
 	  if (place == 0)
 	    {
-	      for (tem = prev_nonnote_insn (i3);
-		   place == 0 && tem
-		   && (GET_CODE (tem) == INSN || GET_CODE (tem) == CALL_INSN);
-		   tem = prev_nonnote_insn (tem))
+	      basic_block bb = BASIC_BLOCK (this_basic_block);
+
+	      for (tem = PREV_INSN (i3); place == 0; tem = PREV_INSN (tem))
+		{
+		  if (GET_RTX_CLASS (GET_CODE (tem)) != 'i')
 		    {
+		      if (tem == bb->head)
+			break;
+		      continue;
+		    }
+
 		  /* If the register is being set at TEM, see if that is all
 		     TEM is doing.  If so, delete TEM.  Otherwise, make this
 		     into a REG_UNUSED note instead.  */
@@ -11789,7 +11795,8 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 			      distribute_links (LOG_LINKS (cc0_setter));
 
 			      PUT_CODE (cc0_setter, NOTE);
-			      NOTE_LINE_NUMBER (cc0_setter) = NOTE_INSN_DELETED;
+			      NOTE_LINE_NUMBER (cc0_setter)
+				= NOTE_INSN_DELETED;
 			      NOTE_SOURCE_FILE (cc0_setter) = 0;
 			    }
 #endif
@@ -11843,23 +11850,39 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 			}
 		      break;
 		    }
+
+		  if (tem == bb->head)
+		    break;
 		}
 	      
-	      /* If we haven't found an insn for the death note and it
-		 is still a REG_DEAD note, but we have hit a CODE_LABEL,
-		 insert a USE insn for the register at that label and
-		 put the death node there.  This prevents problems with
-		 call-state tracking in caller-save.c.  */
-	      if (REG_NOTE_KIND (note) == REG_DEAD && place == 0 && tem != 0)
+	      /* We haven't found an insn for the death note and it
+		 is still a REG_DEAD note, but we have hit the beginning
+		 of the block.  If the existing life info says the reg
+		 was dead, there's nothing left to do.
+
+		 ??? If the register was live, we ought to mark for later
+		 global life update.  Cop out like the previous code and
+		 just add a hook for the death note to live on.  */
+	      if (REG_NOTE_KIND (note) == REG_DEAD && place == 0)
 		{
-		  place
-		    = emit_insn_after (gen_rtx_USE (VOIDmode, XEXP (note, 0)),
-				       tem);
+		  int regno = REGNO (XEXP (note, 0));
 
-		  /* If this insn was emitted between blocks, then update
-		     BLOCK_HEAD of the current block to include it.  */
-		  if (BLOCK_END (this_basic_block - 1) == tem)
-		    BLOCK_HEAD (this_basic_block) = place;
+		  if (REGNO_REG_SET_P (bb->global_live_at_start, regno))
+		    {
+		      rtx die = gen_rtx_USE (VOIDmode, XEXP (note, 0));
+
+		      place = bb->head;
+		      if (GET_CODE (place) != CODE_LABEL
+			  && GET_CODE (place) != NOTE)
+			{
+			  place = emit_insn_before (die, place);
+			  bb->head = place;
+			}
+		      else
+			{
+			  place = emit_insn_after (die, place);
+			}
+		    }
 		}
 	    }
 
@@ -11869,7 +11892,6 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 	     which is what `dead_or_set_p' checks, so also check for it being
 	     set partially.  */
 
-
 	  if (place && REG_NOTE_KIND (note) == REG_DEAD)
 	    {
 	      int regno = REGNO (XEXP (note, 0));

gcc/config/i386/i386.md

@@ -8146,11 +8146,14 @@
 	      (clobber (reg:CC 17))])]
   "")
 
+;; ??? Rewrite these to not introduce the false dependancy.  
+;; Currently they'll trip update_life_info's sanity checks.
+
 ;; For HI and SI modes, or $-1,reg is smaller than mov $-1,reg.
 (define_peephole2
   [(set (match_operand:SI 0 "register_operand" "")
 	(const_int -1))]
-  "(optimize_size || TARGET_PENTIUM)
+  "0 && (optimize_size || TARGET_PENTIUM)
    && reg_dead_p (insn, gen_rtx_REG (CCmode, FLAGS_REG))"
   [(parallel [(set (match_dup 0)
 		   (ior:SI (match_dup 0) (const_int -1)))
@@ -8160,7 +8163,7 @@
 (define_peephole2
   [(set (match_operand:HI 0 "register_operand" "")
 	(const_int -1))]
-  "(optimize_size || TARGET_PENTIUM)
+  "0 && (optimize_size || TARGET_PENTIUM)
    && reg_dead_p (insn, gen_rtx_REG (CCmode, FLAGS_REG))"
   [(parallel [(set (match_dup 0)
 		   (ior:HI (match_dup 0) (const_int -1)))

gcc/haifa-sched.c

@@ -7773,9 +7773,7 @@ schedule_insns (dump_file)
   /* Initialize issue_rate.  */
   issue_rate = ISSUE_RATE;
 
-  /* Do the splitting first for all blocks.  */
-  for (b = 0; b < n_basic_blocks; b++)
-    split_block_insns (b, 1);
+  split_all_insns (1);
 
   max_uid = (get_max_uid () + 1);
 

gcc/output.h

@@ -135,7 +135,6 @@ extern void find_basic_blocks         PROTO((rtx, int, FILE *, int));
 extern void free_basic_block_vars     PROTO((int));
 extern void set_block_num             PROTO((rtx, int));
 extern void life_analysis             PROTO((rtx, int, FILE *, int));
-extern void update_life_info	        PROTO((rtx, rtx, rtx, rtx, rtx));
 #endif
 
 /* Functions in varasm.c.  */

gcc/recog.c

@@ -2562,88 +2562,104 @@ reg_fits_class_p (operand, class, offset, mode)
   return 0;
 }
 
-/* Do the splitting of insns in the block B. Only try to actually split if
-   DO_SPLIT is true; otherwise, just remove nops. */ 
+/* Split all insns in the function.  If UPD_LIFE, update life info after.  */
 
 void
-split_block_insns (b, do_split)
-     int b;
-     int do_split;
+split_all_insns (upd_life)
+     int upd_life;
 {
+  sbitmap blocks;
+  int changed;
+  int i;
+
+  blocks = sbitmap_alloc (n_basic_blocks);
+  sbitmap_zero (blocks);
+  changed = 0;
+
+  for (i = n_basic_blocks - 1; i >= 0; --i)
+    {
+      basic_block bb = BASIC_BLOCK (i);
       rtx insn, next;
 
-  for (insn = BLOCK_HEAD (b);; insn = next)
+      for (insn = bb->head; insn ; insn = next)
 	{
 	  rtx set;
 
-      /* Can't use `next_real_insn' because that
-         might go across CODE_LABELS and short-out basic blocks.  */
+	  /* Can't use `next_real_insn' because that might go across
+	     CODE_LABELS and short-out basic blocks.  */
 	  next = NEXT_INSN (insn);
 	  if (GET_CODE (insn) != INSN)
-	{
-	  if (insn == BLOCK_END (b))
-	    break;
+	    ;
 
-	  continue;
-	}
+	  /* Don't split no-op move insns.  These should silently
+	     disappear later in final.  Splitting such insns would
+	     break the code that handles REG_NO_CONFLICT blocks.  */
 
-      /* Don't split no-op move insns.  These should silently disappear
-         later in final.  Splitting such insns would break the code
-         that handles REG_NO_CONFLICT blocks.  */
-      set = single_set (insn);
-      if (set && rtx_equal_p (SET_SRC (set), SET_DEST (set)))
+	  else if ((set = single_set (insn)) != NULL
+		   && rtx_equal_p (SET_SRC (set), SET_DEST (set)))
 	    {
-	  if (insn == BLOCK_END (b))
-	    break;
-
-	  /* Nops get in the way while scheduling, so delete them now if
-	     register allocation has already been done.  It is too risky
-	     to try to do this before register allocation, and there are
-	     unlikely to be very many nops then anyways.  */
+	      /* Nops get in the way while scheduling, so delete them
+		 now if register allocation has already been done.  It
+		 is too risky to try to do this before register
+		 allocation, and there are unlikely to be very many
+		 nops then anyways.  */
 	      if (reload_completed)
 		{
-
 		  PUT_CODE (insn, NOTE);
 		  NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
 		  NOTE_SOURCE_FILE (insn) = 0;
 		}
-
-	  continue;
 	    }
-
-      if (do_split)
+	  else
 	    {
 	      /* Split insns here to get max fine-grain parallelism.  */
 	      rtx first = PREV_INSN (insn);
-	  rtx notes = REG_NOTES (insn);
 	      rtx last = try_split (PATTERN (insn), insn, 1);
 
 	      if (last != insn)
 		{
+		  SET_BIT (blocks, i);
+		  changed = 1;
+
 		  /* try_split returns the NOTE that INSN became.  */
 		  first = NEXT_INSN (first);
-#ifdef INSN_SCHEDULING
-	      update_life_info (notes, first, last, insn, insn);
-#endif
 		  PUT_CODE (insn, NOTE);
 		  NOTE_SOURCE_FILE (insn) = 0;
 		  NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
-	      if (insn == BLOCK_HEAD (b))
-		BLOCK_HEAD (b) = first;
-	      if (insn == BLOCK_END (b))
+
+		  if (insn == bb->end)
 		    {
-		  BLOCK_END (b) = last;
+		      bb->end = last;
 		      break;
 		    }
 		}
 	    }
 
-      if (insn == BLOCK_END (b))
+	  if (insn == bb->end)
 	    break;
 	}
+
+      /* ??? When we're called from just after reload, the CFG is in bad
+	 shape, and we may have fallen off the end.  This could be fixed
+	 by having reload not try to delete unreachable code.  Otherwise
+	 assert we found the end insn.  */
+      if (insn == NULL && upd_life)
+	abort ();
+    }
+
+  if (changed && upd_life)
+    {
+      count_or_remove_death_notes (blocks, 1);
+      update_life_info (blocks, UPDATE_LIFE_LOCAL);
+    }
+
+  sbitmap_free (blocks);
 }
 
 #ifdef HAVE_peephole2
+/* This is the last insn we'll allow recog_next_insn to consider.  */
+static rtx recog_last_allowed_insn;
+
 /* Return the Nth non-note insn after INSN, or return NULL_RTX if it does
    not exist.  Used by the recognizer to find the next insn to match in a
    multi-insn pattern.  */
@@ -2652,17 +2668,20 @@ recog_next_insn (insn, n)
      rtx insn;
      int n;
 {
-  while (insn != NULL_RTX && n > 0)
+  if (insn != NULL_RTX)
     {
-      insn = next_nonnote_insn (insn);
+      while (n > 0)
+	{
+	  if (insn == recog_last_allowed_insn)
+	    return NULL_RTX;
 
+	  insn = NEXT_INSN (insn);
 	  if (insn == NULL_RTX)
-	return insn;
-
-      if (GET_RTX_CLASS (GET_CODE (insn)) != 'i')
-	return NULL_RTX;
+	    break;
 
-      n--;
+	  if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+	    n -= 1;
+	}
     }
 
   return insn;
@@ -2673,38 +2692,64 @@ void
 peephole2_optimize (dump_file)
      FILE *dump_file ATTRIBUTE_UNUSED;
 {
-  rtx insn;
-  rtx epilogue_insn = 0;
+  rtx insn, prev;
+  int i, changed;
+  sbitmap blocks;
 
-  for (insn = get_last_insn (); insn != NULL_RTX; insn = PREV_INSN (insn))
-    {
-      if (GET_CODE (insn) == NOTE
-	  && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG)
+  /* ??? TODO: Arrange with resource.c to start at bb->global_live_at_end
+     and backtrack insn by insn as we proceed through the block.  In this
+     way we'll not need to keep searching forward from the beginning of 
+     basic blocks to find register life info.  */
+
+  init_resource_info (NULL);
+
+  blocks = sbitmap_alloc (n_basic_blocks);
+  sbitmap_zero (blocks);
+  changed = 0;
+
+  for (i = n_basic_blocks - 1; i >= 0; --i)
     {
-	  epilogue_insn = insn;
-	  break;
-	}
-    }
+      basic_block bb = BASIC_BLOCK (i);
 
-  init_resource_info (epilogue_insn);
+      /* Since we don't update life info until the very end, we can't
+	 allow matching instructions that we've replaced before.  Walk
+	 backward through the basic block so that we don't have to 
+	 care about subsequent life info; recog_last_allowed_insn to
+	 restrict how far forward we will allow the match to proceed.  */
 
-  for (insn = get_insns (); insn != NULL;
-       insn = next_nonnote_insn (insn))
+      recog_last_allowed_insn = bb->end;
+      for (insn = bb->end; ; insn = prev)
 	{
-      if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
+	  prev = PREV_INSN (insn);
+	  if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
 	    {
-	  rtx last_insn;
-	  rtx before = PREV_INSN (insn);
+	      rtx try, last_insn;
 
-	  rtx try = peephole2_insns (PATTERN (insn), insn, &last_insn);
+	      try = peephole2_insns (PATTERN (insn), insn, &last_insn);
 	      if (try != NULL)
 		{
-	      replace_insns (insn, last_insn, try, NULL_RTX);
-	      insn = NEXT_INSN (before);
+		  flow_delete_insn_chain (insn, last_insn);
+		  try = emit_insn_after (try, prev);
+
+		  if (last_insn == bb->end)
+		    bb->end = try;
+		  if (insn == bb->head)
+		    bb->head = NEXT_INSN (prev);
+
+		  recog_last_allowed_insn = prev;
+		  SET_BIT (blocks, i);
+		  changed = 1;
+		}
 	    }
+
+	  if (insn == bb->head)
+	    break;
 	}
     }
 
   free_resource_info ();
+
+  count_or_remove_death_notes (blocks, 1);
+  update_life_info (blocks, UPDATE_LIFE_LOCAL);
 }
 #endif

gcc/rtl.h

@@ -1168,8 +1168,7 @@ extern enum reg_class reg_alternate_class PROTO((int));
 
 extern rtx get_first_nonparm_insn	PROTO((void));
 
-extern void split_block_insns		PROTO((int, int));
-extern void update_flow_info		PROTO((rtx, rtx, rtx, rtx));
+extern void split_all_insns		PROTO((int));
 
 #define MAX_SAVED_CONST_INT 64
 extern rtx const_int_rtx[MAX_SAVED_CONST_INT * 2 + 1];
@@ -1542,7 +1541,6 @@ extern void print_rtl_with_bb		PROTO ((FILE *, rtx));
 extern void dump_flow_info		PROTO ((FILE *));
 #endif
 extern void free_bb_mem			PROTO ((void));
-extern void replace_insns               PROTO ((rtx, rtx, rtx, rtx));
 
 /* In expmed.c */
 extern void init_expmed			PROTO ((void));

gcc/toplev.c

@@ -4149,6 +4149,13 @@ rest_of_compilation (decl)
   if (rebuild_label_notes_after_reload)
     TIMEVAR (jump_time, rebuild_jump_labels (insns));
 
+  /* On some machines, the prologue and epilogue code, or parts thereof,
+     can be represented as RTL.  Doing so lets us schedule insns between
+     it and the rest of the code and also allows delayed branch
+     scheduling to operate in the epilogue.  */
+
+  thread_prologue_and_epilogue_insns (insns);
+
   /* If optimizing and we are performing instruction scheduling after
      reload, then go ahead and split insns now since we are about to
      recompute flow information anyway.
@@ -4156,26 +4163,7 @@ rest_of_compilation (decl)
      reload_cse_regs may expose more splitting opportunities, expecially
      for double-word operations.  */
   if (optimize > 0 && flag_schedule_insns_after_reload)
-    {
-      rtx insn;
-
-      for (insn = insns; insn; insn = NEXT_INSN (insn))
-	{
-	  rtx last;
-
-	  if (GET_RTX_CLASS (GET_CODE (insn)) != 'i')
-	    continue;
-
-	  last = try_split (PATTERN (insn), insn, 1);
-
-	  if (last != insn)
-	    {
-	      PUT_CODE (insn, NOTE);
-	      NOTE_SOURCE_FILE (insn) = 0;
-	      NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
-	    }
-	}
-    }
+    split_all_insns (0);
 
   if (global_reg_dump)
     {
@@ -4204,13 +4192,6 @@ rest_of_compilation (decl)
 
   flow2_completed = 1;
 
-  /* On some machines, the prologue and epilogue code, or parts thereof,
-     can be represented as RTL.  Doing so lets us schedule insns between
-     it and the rest of the code and also allows delayed branch
-     scheduling to operate in the epilogue.  */
-
-  thread_prologue_and_epilogue_insns (insns);
-
   if (flow2_dump)
     {
       close_dump_file (print_rtl_with_bb, insns);