lcm.c (make_preds_opaque): Fix comment.

	* lcm.c (make_preds_opaque): Fix comment.
	(optimize_mode_switching): Use NORMAL_MODE instead of
	MODE_USES_IN_EXIT_BLOCK.  Change leftover instance of
	FP_MODE_NONE to no_mode.  Rename MODE_AT_ENTRY to NORMAL_MODE.
	Handle insertions before an existing NOTE_INSN_BASIC_BLOCK.
	* tm.texi (OPTIMIZE_MODE_SWITCHING): Refer to NORMAL_MODE.
	(MODE_USES_IN_EXIT_BLOCK): Delete.
	(MODE_AT_ENTRY) Rename to NORMAL_MODE.
	* sh.h (MODE_USES_IN_EXIT_BLOCK): Delete.
	(MODE_AT_ENTRY): Rename to NORMAL_MODE.
	(MODE_NEEDED): Don't look for USE.
	(EPILOGUE_USES): Define.

From-SVN: r34243

4 files changed, 60 insertions, 51 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7b644bb..0a6110a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,18 @@
+Sun May 28 18:37:07 2000  Clinton Popetz  <cpopetz@cygnus.com>
+
+	* lcm.c (make_preds_opaque): Fix comment.
+	(optimize_mode_switching): Use NORMAL_MODE instead of 
+	MODE_USES_IN_EXIT_BLOCK.  Change leftover instance of
+	FP_MODE_NONE to no_mode.  Rename MODE_AT_ENTRY to NORMAL_MODE.
+	Handle insertions before an existing NOTE_INSN_BASIC_BLOCK.
+	* tm.texi (OPTIMIZE_MODE_SWITCHING): Refer to NORMAL_MODE.
+	(MODE_USES_IN_EXIT_BLOCK): Delete.
+	(MODE_AT_ENTRY) Rename to NORMAL_MODE.
+	* sh.h (MODE_USES_IN_EXIT_BLOCK): Delete.
+	(MODE_AT_ENTRY): Rename to NORMAL_MODE.
+	(MODE_NEEDED): Don't look for USE.
+	(EPILOGUE_USES): Define.
+
 Sun May 28 23:26:59 2000  Philippe De Muyter <phdm@macqel.be>
 
 	* mklibgcc.in (all): Variable initialised to `libgcc'.
diff --git a/gcc/config/sh/sh.h b/gcc/config/sh/sh.h
index 1cb9344..07c971f 100644
--- a/gcc/config/sh/sh.h
+++ b/gcc/config/sh/sh.h
@@ -2249,19 +2249,16 @@ do {									\
 
 #define OPTIMIZE_MODE_SWITCHING(ENTITY) TARGET_SH4
 
-#define MODE_USES_IN_EXIT_BLOCK gen_rtx_USE (VOIDmode, get_fpscr_rtx ())
+#define NORMAL_MODE(ENTITY) \
+   (TARGET_FPU_SINGLE ? FP_MODE_SINGLE : FP_MODE_DOUBLE) 
+
+#define EPILOGUE_USES(REGNO)       (TARGET_SH4 && (REGNO) == FPSCR_REG)
 
 #define MODE_NEEDED(ENTITY, INSN)					\
   (recog_memoized (INSN) >= 0						\
    ? get_attr_fp_mode (INSN)						\
-   : (GET_CODE (PATTERN (INSN)) == USE				\
-      && rtx_equal_p (XEXP (PATTERN (INSN), 0), get_fpscr_rtx ()))	\
-   ? (TARGET_FPU_SINGLE ? FP_MODE_SINGLE : FP_MODE_DOUBLE)		\
    : FP_MODE_NONE)
 
-#define MODE_AT_ENTRY(ENTITY) \
-  (TARGET_FPU_SINGLE ? FP_MODE_SINGLE : FP_MODE_DOUBLE)
-
 #define MODE_PRIORITY_TO_MODE(ENTITY, N) \
   ((TARGET_FPU_SINGLE != 0) ^ (N) ? FP_MODE_SINGLE : FP_MODE_DOUBLE)
 
diff --git a/gcc/lcm.c b/gcc/lcm.c
index 2f9aaa8..c994654 100644
--- a/gcc/lcm.c
+++ b/gcc/lcm.c
@@ -840,7 +840,7 @@ static sbitmap *comp;
 static sbitmap *delete;
 static sbitmap *insert;
 
-static struct seginfo * new_seginfo PARAMS ((int, rtx, int, HARD_REG_SET));;
+static struct seginfo * new_seginfo PARAMS ((int, rtx, int, HARD_REG_SET));
 static void add_seginfo PARAMS ((struct bb_info *, struct seginfo *));
 static void reg_dies PARAMS ((rtx, HARD_REG_SET));
 static void reg_becomes_live PARAMS ((rtx, rtx, void *));
@@ -850,7 +850,7 @@ static void make_preds_opaque PARAMS ((basic_block, int));
 #ifdef OPTIMIZE_MODE_SWITCHING
 
 /* This function will allocate a new BBINFO structure, initialized
-   with the FP_MODE, INSN, and basic block BB parameters.  */
+   with the MODE, INSN, and basic block BB parameters.  */
 
 static struct seginfo *
 new_seginfo (mode, insn, bb, regs_live)
@@ -994,29 +994,6 @@ optimize_mode_switching (file)
   if (! n_entities)
     return 0;
 
-#ifdef MODE_USES_IN_EXIT_BLOCK
-  /* For some ABIs a particular mode setting is required at function exit.  */
-
-  for (eg = EXIT_BLOCK_PTR->pred; eg; eg = eg->pred_next)
-    {
-      int bb = eg->src->index;
-      rtx insn = BLOCK_END (bb);
-      rtx use = MODE_USES_IN_EXIT_BLOCK;
-
-      /* If the block ends with the use of the return value
-	 and / or a return, insert the new use(s) in front of them.  */
-      while ((GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE)
-	     || GET_CODE (insn) == JUMP_INSN)
-	insn = PREV_INSN (insn);
-
-      use = emit_insn_after (use, insn);
-      if (insn == BLOCK_END (bb))
-	BLOCK_END (bb) = use;
-      else if (NEXT_INSN (use) == BLOCK_HEAD (bb))
-	BLOCK_HEAD (bb) = NEXT_INSN (insn);
-    }
-#endif /* MODE_USES_IN_EXIT_BLOCK */
-
   /* Create the bitmap vectors.  */
 
   antic = sbitmap_vector_alloc (n_basic_blocks, n_entities);
@@ -1071,6 +1048,29 @@ optimize_mode_switching (file)
 		}
 	    }
 
+	  /* If this is a predecessor of the exit block, and we must 
+	     force a mode on exit, make note of that.  */
+#ifdef NORMAL_MODE
+	  if (NORMAL_MODE (e) != no_mode && last_mode != NORMAL_MODE (e))
+	    for (eg = BASIC_BLOCK (bb)->succ; eg; eg = eg->succ_next)
+	      if (eg->dest == EXIT_BLOCK_PTR)
+		{
+		  rtx insn = BLOCK_END (bb);
+
+		  /* Find the last insn before a USE and/or JUMP.  */
+		  while ((GET_CODE (insn) == INSN 
+			      && GET_CODE (PATTERN (insn)) == USE)
+			  || GET_CODE (insn) == JUMP_INSN)
+		    insn = PREV_INSN (insn);
+		  if (insn != BLOCK_END (bb) && NEXT_INSN (insn))
+		    insn = NEXT_INSN (insn);
+		  last_mode = NORMAL_MODE (e);
+		  add_seginfo (info + bb, 
+		      new_seginfo (last_mode, insn, bb, live_now));
+		  RESET_BIT (transp[bb], j);
+		} 
+#endif
+
 	  info[bb].computing = last_mode;
 	  /* Check for blocks without ANY mode requirements.  */
 	  if (last_mode == no_mode)
@@ -1079,9 +1079,9 @@ optimize_mode_switching (file)
 	      add_seginfo (info + bb, ptr);
 	    }
 	}
-#ifdef MODE_AT_ENTRY
+#ifdef NORMAL_MODE
       {
-	int mode = MODE_AT_ENTRY (e);
+	int mode = NORMAL_MODE (e);
 
 	if (mode != no_mode)
 	  {
@@ -1112,7 +1112,7 @@ optimize_mode_switching (file)
 	      }
 	  }
       }
-#endif /* MODE_AT_ENTRY */
+#endif /* NORMAL_MODE */
     }
 
   kill = sbitmap_vector_alloc (n_basic_blocks, n_entities);
@@ -1214,13 +1214,15 @@ optimize_mode_switching (file)
   /* Now output the remaining mode sets in all the segments.  */
   for (j = n_entities - 1; j >= 0; j--)
     {
+      int no_mode = num_modes[entity_map[j]];
+
       for (bb = n_basic_blocks - 1; bb >= 0; bb--)
 	{
 	  struct seginfo *ptr, *next;
 	  for (ptr = bb_info[j][bb].seginfo; ptr; ptr = next)
 	    {
 	      next = ptr->next;
-	      if (ptr->mode != FP_MODE_NONE)
+	      if (ptr->mode != no_mode)
 		{
 		  rtx mode_set;
 
@@ -1229,8 +1231,12 @@ optimize_mode_switching (file)
 		  mode_set = gen_sequence ();
 		  end_sequence ();
 
-		  emit_block_insn_before (mode_set, ptr->insn_ptr,
-					  BASIC_BLOCK (ptr->bbnum));
+		  if (NOTE_LINE_NUMBER (ptr->insn_ptr) == NOTE_INSN_BASIC_BLOCK)
+		    emit_block_insn_after (mode_set, ptr->insn_ptr,
+    		                           BASIC_BLOCK (ptr->bbnum));
+		  else
+		    emit_block_insn_before (mode_set, ptr->insn_ptr,
+					    BASIC_BLOCK (ptr->bbnum));
 		}
 
 	      free (ptr);
diff --git a/gcc/tm.texi b/gcc/tm.texi
index 766ea57..3b3f4b0 100644
--- a/gcc/tm.texi
+++ b/gcc/tm.texi
@@ -7275,7 +7275,7 @@ return non-zero for any @var{entity} that that needs mode-switching.
 If you define this macro, you also have to define
 @code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
 @code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
-@code{MODE_AT_ENTRY} and @code{MODE_USES_IN_EXIT_BLOCK} are optional.
+@code{NORMAL_MODE} is optional.
 
 @findex NUM_MODES_FOR_MODE_SWITCHING
 @item NUM_MODES_FOR_MODE_SWITCHING
@@ -7290,15 +7290,6 @@ In macros that take mode arguments / yield a mode result, modes are
 represented as numbers 0 .. N - 1.  N is used to specify that no mode
 switch is needed / supplied.
 
-@findex MODE_USES_IN_EXIT_BLOCK
-@item MODE_USES_IN_EXIT_BLOCK
-If this macro is defined, it is called for each exit block when mode switching
-optimization is performed.  Its return value should be the pattern of an insn,
-or a sequence of insns.  It is emitted before the return insn / use insns at
-the end of the exit block.
-
-This is done before insns are examined for their need of any mode switching.
-
 @findex MODE_NEEDED
 @item MODE_NEEDED (@var{entity}, @var{insn})
 @var{entity} is an integer specifying a mode-switched entity.  If
@@ -7307,11 +7298,11 @@ return an integer value not larger than the corresponding element in
 NUM_MODES_FOR_MODE_SWITCHING, to denote the mode that @var{entity} must
 be switched into prior to the execution of INSN.
 
-@findex MODE_AT_ENTRY
-@item MODE_AT_ENTRY (@var{entity})
+@findex NORMAL_MODE 
+@item NORMAL_MODE (@var{entity})
 If this macro is defined, it is evaluated for every @var{entity} that needs
 mode switching.  It should evaluate to an integer, which is a mode that
-@var{entity} is assumed to be switched to at function entry.
+@var{entity} is assumed to be switched to at function entry and exit.
 
 @findex MODE_PRIORITY_TO_MODE
 @item MODE_PRIORITY_TO_MODE (@var{entity}, @var{n})