From: Alan Modra <amodra@bigpond.net.au>
Date: Tue, 15 Nov 2005 00:59:21 +0000 (+0000)
Subject: re PR rtl-optimization/22002 (internal consistency failure with -funroll-loops)
X-Git-Tag: releases/gcc-4.1.0~864
X-Git-Url: https://gcc.gnu.org/git/?a=commitdiff_plain;h=46de9b3caffed182eced14f567b27bb77630335f;p=gcc.git

re PR rtl-optimization/22002 (internal consistency failure with -funroll-loops)

	PR rtl-optimization/22002
	* combine.c (distribute_notes): Detect cases where a reg dies
	two or more times in a bb, including on the insn we are combining,
	and place the death note on the correct range.

From-SVN: r106921
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 433f6d0b581..188d5095c03 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2005-11-15  Alan Modra  <amodra@bigpond.net.au>
+
+	PR rtl-optimization/22002
+	* combine.c (distribute_notes): Detect cases where a reg dies
+	two or more times in a bb, including on the insn we are combining,
+	and place the death note on the correct range.
+
 2005-11-14  Dale Johannesen  <dalej@apple.com>
 
 	* expmed.c (store_bit_field):  Add offset unconditionally for
diff --git a/gcc/combine.c b/gcc/combine.c
index 82d260dafbc..9f910a7b336 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -12232,6 +12232,10 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2, rtx elim_i2,
 	    {
 	      basic_block bb = this_basic_block;
 
+	      /* You might think you could search back from FROM_INSN
+		 rather than from I3, but combine tries to split invalid
+		 combined instructions.  This can result in the old I2
+		 or I1 moving later in the insn sequence.  */
 	      for (tem = PREV_INSN (i3); place == 0; tem = PREV_INSN (tem))
 		{
 		  if (! INSN_P (tem))
@@ -12332,6 +12336,22 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2, rtx elim_i2,
 			   || (CALL_P (tem)
 			       && find_reg_fusage (tem, USE, XEXP (note, 0))))
 		    {
+		      /* This may not be the correct place for the death
+			 note if FROM_INSN is before TEM, and the reg is
+			 set between FROM_INSN and TEM.  The reg might
+			 die two or more times.  An existing death note
+			 means we are looking at the wrong live range.  */
+		      if (from_insn
+			  && INSN_CUID (from_insn) < INSN_CUID (tem)
+			  && find_regno_note (tem, REG_DEAD,
+					      REGNO (XEXP (note, 0))))
+			{
+			  tem = from_insn;
+			  if (tem == BB_HEAD (bb))
+			    break;
+			  continue;
+			}
+
 		      place = tem;
 
 		      /* If we are doing a 3->2 combination, and we have a