rtl.texi (jump_insn): Expand on JUMP_LABEL documentation.

	* rtl.texi (jump_insn): Expand on JUMP_LABEL documentation.
	* loop.c (load_mems): Handle a NULL JUMP_LABEL for a JUMP_INSN.

From-SVN: r41424

gcc/ChangeLog

 2001-04-19  Mark Mitchell  <mark@codesourcery.com>
 
+	* rtl.texi (jump_insn): Expand on JUMP_LABEL documentation.
+	* loop.c (load_mems): Handle a NULL JUMP_LABEL for a JUMP_INSN.
+
 	* mips.md (reload_outputdi): Require that operand0 be a
 	general_operand.
 

gcc/loop.c

@@ -8850,10 +8850,13 @@ load_mems (loop)
 	  /* If this is a jump outside of the loop but not right
 	     after the end of the loop, we would have to emit new fixup
 	     sequences for each such label.  */
-	  if (JUMP_LABEL (p) != end_label
-	      && (INSN_UID (JUMP_LABEL (p)) >= max_uid_for_loop
-		  || INSN_LUID (JUMP_LABEL (p)) < INSN_LUID (loop->start)
-		  || INSN_LUID (JUMP_LABEL (p)) > INSN_LUID (loop->end)))
+	  if (/* If we can't tell where control might go when this
+		 JUMP_INSN is executed, we must be conservative.  */
+	      !JUMP_LABEL (p)
+	      || (JUMP_LABEL (p) != end_label
+		  && (INSN_UID (JUMP_LABEL (p)) >= max_uid_for_loop
+		      || INSN_LUID (JUMP_LABEL (p)) < INSN_LUID (loop->start)
+		      || INSN_LUID (JUMP_LABEL (p)) > INSN_LUID (loop->end))))
 	    return;
 
 	  if (!any_condjump_p (p))

gcc/rtl.texi

@@ -2501,14 +2501,15 @@ recorded as a @code{jump_insn}.
 accessed in the same way and in addition contain a field
 @code{JUMP_LABEL} which is defined once jump optimization has completed.
 
-For simple conditional and unconditional jumps, this field contains the
-@code{code_label} to which this insn will (possibly conditionally)
+For simple conditional and unconditional jumps, this field contains
+the @code{code_label} to which this insn will (possibly conditionally)
 branch.  In a more complex jump, @code{JUMP_LABEL} records one of the
-labels that the insn refers to; the only way to find the others
-is to scan the entire body of the insn.
+labels that the insn refers to; the only way to find the others is to
+scan the entire body of the insn.  In an @code{addr_vec},
+@code{JUMP_LABEL} is @code{NULL_RTX}.
 
-Return insns count as jumps, but since they do not refer to any labels,
-they have zero in the @code{JUMP_LABEL} field.
+Return insns count as jumps, but since they do not refer to any
+labels, their @code{JUMP_LABEL} is @code{NULL_RTX}.
 
 @findex call_insn
 @item call_insn