regrename.c (replace_reg_in_block): Improve REG_DEAD handling.

	* regrename.c (replace_reg_in_block): Improve REG_DEAD handling.
	* timevar.def (TV_RENAME_REGISTERS): Move before TV_SCHED2.
	* toplev.c (rest_of_compilation): Call regrename_optimize before sched2.

From-SVN: r33845

4 files changed, 86 insertions, 31 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e26be78..3a7c61e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2000-05-11 Stan Cox <scox@cygnus.com>
+
+	* regrename.c (replace_reg_in_block): Improve REG_DEAD handling.
+	* timevar.def (TV_RENAME_REGISTERS): Move before TV_SCHED2.
+	* toplev.c (rest_of_compilation): Call regrename_optimize before sched2.
+
 2000-05-11  Bruce Korb  <bkorb@gnu.org>
 
 	* fixinc/fixfixes.c(double_slash_fix):  obsolete
diff --git a/gcc/regrename.c b/gcc/regrename.c
index 2612949..d5e8160 100644
--- a/gcc/regrename.c
+++ b/gcc/regrename.c
@@ -526,8 +526,11 @@ replace_reg_in_block (du, uid_ruid, def, reg_def, avail_reg)
      unsigned int avail_reg;
 {
   int du_idx, status = 1;
+  int last_replaced_insn;
   unsigned int r = REGNO (reg_def);
   rtx death_note;
+  rtx reg_notes;
+  rtx reg_use;
   rtx new_reg = gen_rtx_REG (GET_MODE (reg_def), avail_reg);
 
   rr_replace_reg (PATTERN (VARRAY_RTX (*uid_ruid, def)), reg_def, new_reg,
@@ -536,39 +539,64 @@ replace_reg_in_block (du, uid_ruid, def, reg_def, avail_reg)
   if (!status)
     return status;
 
-  death_note = find_reg_note (VARRAY_RTX (*uid_ruid, def), REG_DEAD, reg_def);
-  if (!death_note)
-    death_note = find_reg_note (VARRAY_RTX (*uid_ruid, def), REG_UNUSED,
-				reg_def);
+  death_note = 0;
+  /* This typically happens if a constraint check failed and the register
+     changes are being reversed. */
+  for (reg_notes = REG_NOTES (VARRAY_RTX (*uid_ruid, def));
+       reg_notes; reg_notes = XEXP (reg_notes, 1))
+    {
+      if (REG_NOTE_KIND (reg_notes) == REG_DEAD
+	  && REGNO (XEXP (reg_notes, 0)) == avail_reg)
+	death_note = reg_notes;
+    }
 
   if (death_note)
-    rr_replace_reg (death_note, reg_def, new_reg, 0,
-		    VARRAY_RTX (*uid_ruid, def), &status);
+    remove_note (VARRAY_RTX (*uid_ruid, def), death_note);
+  
+  /* The old destination is now dead if it is also a source. */
+  if (regno_use_in (r, PATTERN (VARRAY_RTX (*uid_ruid, def))))
+    REG_NOTES (VARRAY_RTX (*uid_ruid, def))
+      = gen_rtx_EXPR_LIST (REG_DEAD, reg_def,
+			   REG_NOTES (VARRAY_RTX (*uid_ruid,
+						  def)));
+
+  last_replaced_insn = 0;
 
+  /* Now replace in the uses. */
   for (du_idx = def + 1; du_idx < du->high_bound; du_idx++)
     {
-      rtx reg_use;
-      rtx new_reg;
-
       if (GET_RTX_CLASS (GET_CODE (VARRAY_RTX (*uid_ruid, du_idx))) != 'i')
 	continue;
 
       reg_use = regno_use_in (r, PATTERN (VARRAY_RTX (*uid_ruid, du_idx)));
+
       if (reg_use && TEST_BIT (du->uses[r], du_idx))
 	{
 	  new_reg = gen_rtx_REG (GET_MODE (reg_use), avail_reg);
+	  
 	  rr_replace_reg (PATTERN (VARRAY_RTX (*uid_ruid, du_idx)), reg_use,
 			  new_reg, SOURCE, VARRAY_RTX (*uid_ruid, du_idx),
 			  &status);
 	  death_note = find_reg_note (VARRAY_RTX (*uid_ruid, du_idx),
 				      REG_DEAD, reg_use);
-	  if (!death_note)
-	    death_note = find_reg_note (VARRAY_RTX (*uid_ruid, du_idx),
-					REG_UNUSED, reg_use);
 	  if (death_note)
-	    rr_replace_reg (death_note, reg_use, new_reg, 0,
-			    VARRAY_RTX (*uid_ruid, def), &status);
+	    {
+	      REG_NOTES (VARRAY_RTX (*uid_ruid, du_idx))
+		= gen_rtx_EXPR_LIST (REG_DEAD, new_reg,
+				     REG_NOTES (VARRAY_RTX (*uid_ruid,
+							    du_idx)));
+	      remove_note (VARRAY_RTX (*uid_ruid, du_idx),
+			   find_reg_note (VARRAY_RTX (*uid_ruid, du_idx),
+					  REG_DEAD, reg_use));
+	    }
+	}
 
+      /* This insn may contain shared rtl replaced in the previous iteration.
+	 Treat this equivalent to the rr_replace_reg case. */
+      if (TEST_BIT (du->uses[r], du_idx))
+	{
+	  last_replaced_insn = du_idx;
+	  
 	  SET_BIT (du->uses[avail_reg], du_idx);
 	  RESET_BIT (du->uses[r], du_idx);
 	  if (!status)
@@ -579,6 +607,27 @@ replace_reg_in_block (du, uid_ruid, def, reg_def, avail_reg)
 	break;
     }
 
+  /* Add REG_DEAD note for replaced register at last use. */
+
+  if (last_replaced_insn)
+    {
+      new_reg = regno_use_in (avail_reg,
+			      PATTERN (VARRAY_RTX (*uid_ruid,
+						   last_replaced_insn)));
+      if (new_reg
+	  && ! find_reg_note (VARRAY_RTX (*uid_ruid, last_replaced_insn),
+				      REG_DEAD, new_reg))
+	{
+	  REG_NOTES (VARRAY_RTX (*uid_ruid, last_replaced_insn))
+	    = gen_rtx_EXPR_LIST (REG_DEAD, new_reg,
+				 REG_NOTES (VARRAY_RTX (*uid_ruid,
+							last_replaced_insn)));
+	  remove_note (VARRAY_RTX (*uid_ruid, last_replaced_insn),
+		       find_reg_note (VARRAY_RTX (*uid_ruid, last_replaced_insn),
+					    REG_DEAD, reg_use));
+	}
+    }
+
   return status;
 }
 
@@ -611,7 +660,7 @@ rr_replace_reg (x, reg_use, reg_sub, replace_type, insn, status)
 	  if (GET_MODE (x) == GET_MODE (reg_use))
 	    return reg_sub;
 	  else
-	    return gen_rtx_REG (GET_MODE (x), REGNO (reg_use));
+	    return gen_rtx_REG (GET_MODE (x), REGNO (reg_sub));
 	}
 
       return x;
diff --git a/gcc/timevar.def b/gcc/timevar.def
index 401719a..fcf2177 100644
--- a/gcc/timevar.def
+++ b/gcc/timevar.def
@@ -60,10 +60,10 @@ DEFTIMEVAR (TV_RELOAD_CSE_REGS       , "reload CSE regs")
 DEFTIMEVAR (TV_FLOW2                 , "flow 2")
 DEFTIMEVAR (TV_IFCVT2		     , "if-conversion 2")
 DEFTIMEVAR (TV_PEEPHOLE2             , "peephole 2")
-DEFTIMEVAR (TV_SCHED2                , "schedulding 2")
+DEFTIMEVAR (TV_RENAME_REGISTERS      , "rename registers")
+DEFTIMEVAR (TV_SCHED2                , "scheduling 2")
 DEFTIMEVAR (TV_DBR_SCHED             , "delay branch sched")
 DEFTIMEVAR (TV_REORDER_BLOCKS        , "reorder blocks")
-DEFTIMEVAR (TV_RENAME_REGISTERS      , "rename registers")
 DEFTIMEVAR (TV_SHORTEN_BRANCH        , "shorten branches")
 DEFTIMEVAR (TV_REG_STACK             , "reg stack")
 DEFTIMEVAR (TV_TO_SSA                , "convert to SSA")
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 05d1846..1d89a7c 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -272,9 +272,9 @@ enum dump_file_index
   DFI_flow2,
   DFI_ce2,
   DFI_peephole2,
+  DFI_rnreg,
   DFI_sched2,
   DFI_bbro,
-  DFI_rnreg,
   DFI_jump2,
   DFI_mach,
   DFI_dbr,
@@ -314,9 +314,9 @@ struct dump_file_info dump_file[DFI_MAX] =
   { "flow2",	'w', 1, 0, 0 },
   { "ce2",	'E', 1, 0, 0 },
   { "peephole2", 'z', 1, 0, 0 },
+  { "rnreg",	'n', 1, 0, 0 },
   { "sched2",	'R', 1, 0, 0 },
   { "bbro",	'B', 1, 0, 0 },
-  { "rnreg",	'n', 1, 0, 0 },
   { "jump2",	'J', 1, 0, 0 },
   { "mach",	'M', 1, 0, 0 },
   { "dbr",	'd', 0, 0, 0 },
@@ -3358,7 +3358,7 @@ rest_of_compilation (decl)
       cleanup_cfg (insns);
       life_analysis (insns, rtl_dump_file, PROP_FINAL);
 
-      /* This is kind of heruistics.  We need to run combine_stack_adjustments
+      /* This is kind of a heuristic.  We need to run combine_stack_adjustments
          even for machines with possibly nonzero RETURN_POPS_ARGS
          and ACCUMULATE_OUTGOING_ARGS.  We expect that only ports having
          push instructions will have popping returns.  */
@@ -3400,6 +3400,17 @@ rest_of_compilation (decl)
     }
 #endif
 
+  if (optimize > 0 && flag_rename_registers)
+    {
+      timevar_push (TV_RENAME_REGISTERS);
+      open_dump_file (DFI_rnreg, decl);
+
+      regrename_optimize ();
+
+      close_dump_file (DFI_rnreg, print_rtl_with_bb, insns);
+      timevar_pop (TV_RENAME_REGISTERS);
+    }    
+
 #ifdef INSN_SCHEDULING
   if (optimize > 0 && flag_schedule_insns_after_reload)
     {
@@ -3435,17 +3446,6 @@ rest_of_compilation (decl)
       timevar_pop (TV_REORDER_BLOCKS);
     }    
 
-  if (optimize > 0 && flag_rename_registers)
-    {
-      timevar_push (TV_RENAME_REGISTERS);
-      open_dump_file (DFI_rnreg, decl);
-
-      regrename_optimize ();
-
-      close_dump_file (DFI_rnreg, print_rtl_with_bb, insns);
-      timevar_pop (TV_RENAME_REGISTERS);
-    }    
-
   /* One more attempt to remove jumps to .+1 left by dead-store elimination. 
      Also do cross-jumping this time and delete no-op move insns.  */