rtl.h (REG_EH_REGION): Update comment to indicate a value of -1 indicates no…

rtl.h (REG_EH_REGION): Update comment to indicate a value of -1 indicates no throw and no nonlocal gotos.

Tue Apr 27 19:50:25 EDT 1999  Andrew MacLeod  <amacleod@cygnus.com>
	* rtl.h (REG_EH_REGION): Update comment to indicate a value of -1
	indicates no throw and no nonlocal gotos.
	* optabs.c (emit_libcall_block): Emit REG_EH_REGION with a value
	of -1 instead of 0 to indicate a nonlocal goto won't happen either.
	* flow.c (count_basic_blocks, find_basic_blocks_1): Ignore libcall
	blocks, look for REG_EH_REGION note exclusively.
	(make_edges): Check for REG_EH_REGION > 0 for specified handlers.

From-SVN: r26680

gcc/ChangeLog

+Tue Apr 27 19:50:25 EDT 1999  Andrew MacLeod  <amacleod@cygnus.com>
+
+	* rtl.h (REG_EH_REGION): Update comment to indicate a value of -1
+	indicates no throw and no nonlocal gotos.
+	* optabs.c (emit_libcall_block): Emit REG_EH_REGION with a value
+	of -1 instead of 0 to indicate a nonlocal goto won't happen either.
+	* flow.c (count_basic_blocks, find_basic_blocks_1): Ignore libcall
+	blocks, look for REG_EH_REGION note exclusively.
+	(make_edges): Check for REG_EH_REGION > 0 for specified handlers.
+
 Tue Apr 27 15:33:42 1999  David Edelsohn  <edelsohn@gnu.org>
 
 	* rs6000.h (read_only_data_section, private_data_section,
@@ -124,7 +134,7 @@ Mon Apr 26 15:27:33 1999  Mark Mitchell  <mark@codesourcery.com>
 	* fixinc/inclhack.tpl: Remove unnecessary character quote
 	* fixinc/fixincl.sh, fixinc/inclhack.sh: Regenerate
 
-Mon Apr 26 10:41:42 EDT 1999  <amacleod@cygnus.com>
+Mon Apr 26 10:41:42 EDT 1999  Andrew MacLeod  <amacleod@cygnus.com>
 
 	* alpha.md (builtin_setjmp_receiver): Use a label_ref instead of 
 	a code label.

gcc/flow.c

@@ -435,7 +435,6 @@ count_basic_blocks (f)
   register RTX_CODE prev_code;
   register int count = 0;
   int eh_region = 0;
-  int in_libcall_block = 0;
   int call_had_abnormal_edge = 0;
   rtx prev_call = NULL_RTX;
 
@@ -444,11 +443,6 @@ count_basic_blocks (f)
     {
       register RTX_CODE code = GET_CODE (insn);
 
-      /* Track when we are inside in LIBCALL block.  */
-      if (GET_RTX_CLASS (code) == 'i'
-	  && find_reg_note (insn, REG_LIBCALL, NULL_RTX))
-	in_libcall_block = 1;
-
       if (code == CODE_LABEL
 	  || (GET_RTX_CLASS (code) == 'i'
 	      && (prev_code == JUMP_INSN
@@ -473,14 +467,20 @@ count_basic_blocks (f)
       /* Record whether this call created an edge.  */
       if (code == CALL_INSN)
 	{
+	  rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
+	  int region = (note ? XINT (XEXP (note, 0), 0) : 1);
 	  prev_call = insn;
 	  call_had_abnormal_edge = 0;
-	  if (nonlocal_goto_handler_labels)
-	    call_had_abnormal_edge = !in_libcall_block;
-	  else if (eh_region)
+
+	  /* If there is a specified EH region, we have an edge.  */
+	  if (eh_region && region > 0)
+	    call_had_abnormal_edge = 1;
+	  else
 	    {
-	      rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
-	      if (!note || XINT (XEXP (note, 0), 0) != 0)
+	      /* If there is a nonlocal goto label and the specified
+		 region number isn't -1, we have an edge. (0 means
+		 no throw, but might have a nonlocal goto).  */
+	      if (nonlocal_goto_handler_labels && region >= 0)
 		call_had_abnormal_edge = 1;
 	    }
 	}
@@ -494,9 +494,6 @@ count_basic_blocks (f)
       else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
 	--eh_region;
 
-      if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
-	  && find_reg_note (insn, REG_RETVAL, NULL_RTX))
-	in_libcall_block = 0;
     }
 
   /* The rest of the compiler works a bit smoother when we don't have to
@@ -527,7 +524,6 @@ find_basic_blocks_1 (f, bb_eh_end)
      rtx *bb_eh_end;
 {
   register rtx insn, next;
-  int in_libcall_block = 0;
   int call_has_abnormal_edge = 0;
   int i = 0;
   rtx bb_note = NULL_RTX;
@@ -548,21 +544,22 @@ find_basic_blocks_1 (f, bb_eh_end)
 
       next = NEXT_INSN (insn);
 
-      /* Track when we are inside in LIBCALL block.  */
-      if (GET_RTX_CLASS (code) == 'i'
-	  && find_reg_note (insn, REG_LIBCALL, NULL_RTX))
-	in_libcall_block = 1;
-
       if (code == CALL_INSN)
 	{
 	  /* Record whether this call created an edge.  */
+	  rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
+	  int region = (note ? XINT (XEXP (note, 0), 0) : 1);
 	  call_has_abnormal_edge = 0;
-	  if (nonlocal_goto_handler_labels)
-	    call_has_abnormal_edge = !in_libcall_block;
-	  else if (eh_list)
+
+	  /* If there is an EH region, we have an edge.  */
+	  if (eh_list && region > 0)
+	    call_has_abnormal_edge = 1;
+	  else
 	    {
-	      rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
-	      if (!note || XINT (XEXP (note, 0), 0) != 0)
+	      /* If there is a nonlocal goto label and the specified
+		 region number isn't -1, we have an edge. (0 means
+		 no throw, but might have a nonlocal goto).  */
+	      if (nonlocal_goto_handler_labels && region >= 0)
 		call_has_abnormal_edge = 1;
 	    }
 	}
@@ -722,9 +719,6 @@ find_basic_blocks_1 (f, bb_eh_end)
 		    = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
 				         label_value_list);
 	      }
-
-	  if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
-	    in_libcall_block = 0;
 	}
     }
 
@@ -996,7 +990,7 @@ make_edges (label_value_list, bb_eh_end)
 	    x = find_reg_note (insn, REG_EH_REGION, 0);
 	  if (x)
 	    {
-	      if (XINT (XEXP (x, 0), 0) != 0)
+	      if (XINT (XEXP (x, 0), 0) > 0)
 		{
 		  ptr = get_first_handler (XINT (XEXP (x, 0), 0));
 		  while (ptr)

gcc/optabs.c

@@ -2604,7 +2604,7 @@ emit_libcall_block (insns, target, result, equiv)
         {
           rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
           if (note == NULL_RTX)
-            REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EH_REGION, GEN_INT (0),
+            REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EH_REGION, GEN_INT (-1),
                                                   REG_NOTES (insn));
         }
     }

gcc/rtl.h

@@ -344,7 +344,9 @@ typedef struct rtvec_def{
    rtx is used instead of intuition.  */
 /*   REG_EH_REGION is used to indicate what exception region an INSN
    belongs in.  This can be used to indicate what region a call may throw
-   to. a REGION of 0 indicates that a call cannot throw at all.
+   to.  A REGION of 0 indicates that a call cannot throw at all.
+   A REGION  of -1 indicates that it cannot throw, nor will it execute
+   a non-local goto.
      REG_EH_RETHROW is used to indicate what that a call is actually a
    call to rethrow, and specifies which region the rethrow is targetting.
    This provides a way to generate the non standard flow edges required