calls.c (ECF_ALWAYS_RETURN): New constant.

	* calls.c (ECF_ALWAYS_RETURN): New constant.
	(emit_call_1): Add REG_ALWAYS_RETURN note if needed.
	(expand_call): Use LCF_ALWAYS_RETURN for __bb_fork_func.
	(emit_library_call_value_1): Handle LCT_ALWAYS_RETRUN.
	* flow.c (need_fake_edge_p): Handle REG_ALWAYS_RETURN.
	* rtl.c (reg_note_name): New name.
	* rtl.h (enum reg_note): Add REG_ALWAYS_RETURN.

From-SVN: r44722

gcc/ChangeLog

+Wed Aug  8 21:06:43 CEST 2001  Jan Hubicka  <jh@suse.cz>
+
+	* calls.c (ECF_ALWAYS_RETURN): New constant.
+	(emit_call_1): Add REG_ALWAYS_RETURN note if needed.
+	(expand_call): Use LCF_ALWAYS_RETURN for __bb_fork_func.
+	(emit_library_call_value_1): Handle LCT_ALWAYS_RETRUN.
+	* flow.c (need_fake_edge_p): Handle REG_ALWAYS_RETURN.
+	* rtl.c (reg_note_name): New name.
+	* rtl.h (enum reg_note): Add REG_ALWAYS_RETURN.
+
 2001-08-07  Aldy Hernandez  <aldyh@redhat.com>
 
 	* config/mips/mips.c (mips_legitimate_address_p): Limit "la" addresses.

gcc/calls.c

@@ -177,6 +177,8 @@ static int calls_function_1	PARAMS ((tree, int));
 /* Nonzero if this is a call to a function that returns with the stack
    pointer depressed.  */
 #define ECF_SP_DEPRESSED	1024
+/* Nonzero if this call is known to always return.  */
+#define ECF_ALWAYS_RETURN	2048
 
 static void emit_call_1		PARAMS ((rtx, tree, tree, HOST_WIDE_INT,
 					 HOST_WIDE_INT, HOST_WIDE_INT, rtx,
@@ -609,6 +611,9 @@ emit_call_1 (funexp, fndecl, funtype, stack_size, rounded_stack_size,
   if (ecf_flags & ECF_NORETURN)
     REG_NOTES (call_insn) = gen_rtx_EXPR_LIST (REG_NORETURN, const0_rtx,
 					       REG_NOTES (call_insn));
+  if (ecf_flags & ECF_ALWAYS_RETURN)
+    REG_NOTES (call_insn) = gen_rtx_EXPR_LIST (REG_ALWAYS_RETURN, const0_rtx,
+					       REG_NOTES (call_insn));
 
   if (ecf_flags & ECF_RETURNS_TWICE)
     REG_NOTES (call_insn) = gen_rtx_EXPR_LIST (REG_SETJMP, const0_rtx,
@@ -2594,7 +2599,8 @@ expand_call (exp, target, ignore)
 	 is subject to race conditions, just as with multithreaded
 	 programs.  */
 
-      emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__bb_fork_func"), 0,
+      emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__bb_fork_func"),
+		      	 LCT_ALWAYS_RETURN,
 			 VOIDmode, 0);
     }
 
@@ -3546,6 +3552,9 @@ emit_library_call_value_1 (retval, orgfun, value, fn_type, outmode, nargs, p)
     case LCT_THROW:
       flags = ECF_NORETURN;
       break;
+    case LCT_ALWAYS_RETURN:
+      flags = ECF_ALWAYS_RETURN;
+      break;
     }
   fun = orgfun;
 

gcc/flow.c

@@ -2517,6 +2517,7 @@ need_fake_edge_p (insn)
   if ((GET_CODE (insn) == CALL_INSN
        && !SIBLING_CALL_P (insn)
        && !find_reg_note (insn, REG_NORETURN, NULL)
+       && !find_reg_note (insn, REG_ALWAYS_RETURN, NULL)
        && !CONST_OR_PURE_CALL_P (insn)))
     return true;
 

gcc/rtl.c

@@ -281,7 +281,7 @@ const char * const reg_note_name[] =
   "REG_EXEC_COUNT", "REG_NOALIAS", "REG_SAVE_AREA", "REG_BR_PRED",
   "REG_FRAME_RELATED_EXPR", "REG_EH_CONTEXT", "REG_EH_REGION",
   "REG_EH_RETHROW", "REG_SAVE_NOTE", "REG_MAYBE_DEAD", "REG_NORETURN",
-  "REG_NON_LOCAL_GOTO", "REG_SETJMP"
+  "REG_NON_LOCAL_GOTO", "REG_SETJMP", "REG_ALWAYS_RETURN"
 };
 
 

gcc/rtl.h

@@ -566,7 +566,10 @@ enum reg_note
 
   /* This kind of note is generated at each to `setjmp',
      and similar functions that can return twice.  */
-  REG_SETJMP
+  REG_SETJMP,
+
+  /* Indicate calls that always returns.  */
+  REG_ALWAYS_RETURN
 };
 
 /* The base value for branch probability notes.  */
@@ -1952,7 +1955,8 @@ enum libcall_type
   LCT_CONST_MAKE_BLOCK = 3,
   LCT_PURE_MAKE_BLOCK = 4,
   LCT_NORETURN = 5,
-  LCT_THROW = 6
+  LCT_THROW = 6,
+  LCT_ALWAYS_RETURN = 7
 };
 
 extern void emit_library_call		PARAMS ((rtx, enum libcall_type,