cfgcleanup.c (mentions_nonequal_regs): New function.

	* cfgcleanup.c (mentions_nonequal_regs): New function.
	(thread_jump): Use it.
	* toplev.c (rest_of_compilation): Run jump threading after
	liveness.

From-SVN: r50361

gcc/ChangeLog

+Wed Mar  6 18:14:43 CET 2002  Jan Hubicka  <jh@suse.cz>
+
+	* cfgcleanup.c (mentions_nonequal_regs): New function.
+	(thread_jump): Use it.
+	* toplev.c (rest_of_compilation): Run jump threading after
+	liveness.
+
 2002-03-06  Jakub Jelinek  <jakub@redhat.com>
 
 	* ssa-ccp.c (ssa_ccp_substitute_constants): Backout 2002-03-05

gcc/cfgcleanup.c

@@ -89,6 +89,7 @@ static edge thread_jump			PARAMS ((int, edge, basic_block));
 static bool mark_effect			PARAMS ((rtx, bitmap));
 static void notice_new_block		PARAMS ((basic_block));
 static void update_forwarder_flag	PARAMS ((basic_block));
+static int mentions_nonequal_regs	PARAMS ((rtx *, void *));
 
 /* Set flags for newly created block.  */
 
@@ -235,6 +236,32 @@ mark_effect (exp, nonequal)
 	return false;
     }
 }
+
+/* Return nonzero if X is an register set in regset DATA.
+   Called via for_each_rtx.  */
+static int
+mentions_nonequal_regs (x, data)
+     rtx *x;
+     void *data;
+{
+  regset nonequal = (regset) data;
+  if (REG_P (*x))
+    {
+      int regno;
+
+      regno = REGNO (*x);
+      if (REGNO_REG_SET_P (nonequal, regno))
+	return 1;
+      if (regno < FIRST_PSEUDO_REGISTER)
+	{
+	  int n = HARD_REGNO_NREGS (regno, GET_MODE (*x));
+	  while (--n > 0)
+	    if (REGNO_REG_SET_P (nonequal, regno + n))
+	      return 1;
+	}
+    }
+  return 0;
+}
 /* Attempt to prove that the basic block B will have no side effects and
    allways continues in the same edge if reached via E.  Return the edge
    if exist, NULL otherwise.  */
@@ -338,6 +365,11 @@ thread_jump (mode, e, b)
   if (failed)
     goto failed_exit;
 
+  /* cond2 must not mention any register that is not equal to the
+     former block.  */
+  if (for_each_rtx (&cond2, mentions_nonequal_regs, nonequal))
+    goto failed_exit;
+
   /* In case liveness information is available, we need to prove equivalence
      only of the live values.  */
   if (mode & CLEANUP_UPDATE_LIFE)

gcc/toplev.c

@@ -3019,7 +3019,8 @@ rest_of_compilation (decl)
 #endif
   life_analysis (insns, rtl_dump_file, PROP_FINAL);
   if (optimize)
-    cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_UPDATE_LIFE);
+    cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0)
+		 | (flag_thread_jumps ? CLEANUP_THREADING : 0));
   timevar_pop (TV_FLOW);
 
   no_new_pseudos = 1;