From c8f5fc7032940ad6633f932ac40cade82ec4d0cc Mon Sep 17 00:00:00 2001
From: obrien <obrien@FreeBSD.org>
Date: Thu, 9 May 2002 20:02:13 +0000
Subject: Gcc 3.1.0 pre-release from the FSF anoncvs repo on 9-May-2002
 15:57:15 EDT.

---
 contrib/gcc/sched-rgn.c | 52 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 8 deletions(-)

(limited to 'contrib/gcc/sched-rgn.c')

diff --git a/contrib/gcc/sched-rgn.c b/contrib/gcc/sched-rgn.c
index e5a241b..ab65e2c 100644
--- a/contrib/gcc/sched-rgn.c
+++ b/contrib/gcc/sched-rgn.c
@@ -294,6 +294,8 @@ static int haifa_classify_insn PARAMS ((rtx));
 static int is_prisky PARAMS ((rtx, int, int));
 static int is_exception_free PARAMS ((rtx, int, int));
 
+static bool sets_likely_spilled PARAMS ((rtx));
+static void sets_likely_spilled_1 PARAMS ((rtx, rtx, void *));
 static void add_branch_dependences PARAMS ((rtx, rtx));
 static void compute_block_backward_dependences PARAMS ((int));
 void debug_dependencies PARAMS ((void));
@@ -337,7 +339,7 @@ is_cfg_nonregular ()
   /* If we have exception handlers, then we consider the cfg not well
      structured.  ?!?  We should be able to handle this now that flow.c
      computes an accurate cfg for EH.  */
-  if (exception_handler_labels)
+  if (current_function_has_exception_handlers ())
     return 1;
 
   /* If we have non-jumping insns which refer to labels, then we consider
@@ -2268,6 +2270,31 @@ static struct sched_info region_sched_info =
   0, 0
 };
 
+/* Determine if PAT sets a CLASS_LIKELY_SPILLED_P register.  */
+
+static bool
+sets_likely_spilled (pat)
+     rtx pat;
+{
+  bool ret = false;
+  note_stores (pat, sets_likely_spilled_1, &ret);
+  return ret;
+}
+
+static void
+sets_likely_spilled_1 (x, pat, data)
+     rtx x, pat;
+     void *data;
+{
+  bool *ret = (bool *) data;
+
+  if (GET_CODE (pat) == SET
+      && REG_P (x)
+      && REGNO (x) < FIRST_PSEUDO_REGISTER
+      && CLASS_LIKELY_SPILLED_P (REGNO_REG_CLASS (REGNO (x))))
+    *ret = true;
+}
+
 /* Add dependences so that branches are scheduled to run last in their
    block.  */
 
@@ -2277,15 +2304,22 @@ add_branch_dependences (head, tail)
 {
   rtx insn, last;
 
-  /* For all branches, calls, uses, clobbers, and cc0 setters, force them
-     to remain in order at the end of the block by adding dependencies and
-     giving the last a high priority.  There may be notes present, and
-     prev_head may also be a note.
+  /* For all branches, calls, uses, clobbers, cc0 setters, and instructions
+     that can throw exceptions, force them to remain in order at the end of
+     the block by adding dependencies and giving the last a high priority.
+     There may be notes present, and prev_head may also be a note.
 
      Branches must obviously remain at the end.  Calls should remain at the
      end since moving them results in worse register allocation.  Uses remain
-     at the end to ensure proper register allocation.  cc0 setters remaim
-     at the end because they can't be moved away from their cc0 user.  */
+     at the end to ensure proper register allocation.
+
+     cc0 setters remaim at the end because they can't be moved away from
+     their cc0 user.
+
+     Insns setting CLASS_LIKELY_SPILLED_P registers (usually return values)
+     are not moved before reload because we can wind up with register
+     allocation failures.  */
+
   insn = tail;
   last = 0;
   while (GET_CODE (insn) == CALL_INSN
@@ -2293,10 +2327,12 @@ add_branch_dependences (head, tail)
 	 || (GET_CODE (insn) == INSN
 	     && (GET_CODE (PATTERN (insn)) == USE
 		 || GET_CODE (PATTERN (insn)) == CLOBBER
+		 || can_throw_internal (insn)
 #ifdef HAVE_cc0
 		 || sets_cc0_p (PATTERN (insn))
 #endif
-	     ))
+		 || (!reload_completed
+		     && sets_likely_spilled (PATTERN (insn)))))
 	 || GET_CODE (insn) == NOTE)
     {
       if (GET_CODE (insn) != NOTE)
-- 
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