Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog	(revision 215550)
+++ gcc/ChangeLog	(working copy)
@@ -1,3 +1,11 @@
+2014-09-24  Felix Yang  <felix.yang@huawei.com>
+
+	* ira.c (struct equivalence): Add no_equiv member.
+	(no_equiv): Set no_equiv of struct equivalence if register is marked
+	as having no known equivalence.
+	(update_equiv_regs): Check all definitions for a multiple-set
+	register to make sure that the RHS have the same value.
+
 2014-09-24  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/63316
Index: gcc/ira.c
===================================================================
--- gcc/ira.c	(revision 215550)
+++ gcc/ira.c	(working copy)
@@ -2900,6 +2900,8 @@ struct equivalence
   /* Set when an attempt should be made to replace a register
      with the associated src_p entry.  */
   char replace;
+  /* Set if this register has no known equivalence.  */
+  char no_equiv;
 };
 
 /* reg_equiv[N] (where N is a pseudo reg number) is the equivalence
@@ -3247,6 +3249,7 @@ no_equiv (rtx reg, const_rtx store ATTRIBUTE_UNUSE
   if (!REG_P (reg))
     return;
   regno = REGNO (reg);
+  reg_equiv[regno].no_equiv = 1;
   list = reg_equiv[regno].init_insns;
   if (list == const0_rtx)
     return;
@@ -3258,7 +3261,7 @@ no_equiv (rtx reg, const_rtx store ATTRIBUTE_UNUSE
     return;
   ira_reg_equiv[regno].defined_p = false;
   ira_reg_equiv[regno].init_insns = NULL;
-  for (; list; list =  XEXP (list, 1))
+  for (; list; list = XEXP (list, 1))
     {
       rtx insn = XEXP (list, 0);
       remove_note (insn, find_reg_note (insn, REG_EQUIV, NULL_RTX));
@@ -3373,7 +3376,7 @@ update_equiv_regs (void)
 
 	  /* If this insn contains more (or less) than a single SET,
 	     only mark all destinations as having no known equivalence.  */
-	  if (set == 0)
+	  if (set == NULL_RTX)
 	    {
 	      note_stores (PATTERN (insn), no_equiv, NULL);
 	      continue;
@@ -3467,16 +3470,48 @@ update_equiv_regs (void)
 	  if (note && GET_CODE (XEXP (note, 0)) == EXPR_LIST)
 	    note = NULL_RTX;
 
-	  if (DF_REG_DEF_COUNT (regno) != 1
-	      && (! note
+	  if (DF_REG_DEF_COUNT (regno) != 1)
+	    {
+	      rtx list;
+	      bool equal_p = true;
+
+              /* Check if it is possible that this multiple-set register has
+		 a known equivalence.  */
+	      if (reg_equiv[regno].no_equiv)
+		continue;
+
+	      if (! note
 		  || rtx_varies_p (XEXP (note, 0), 0)
 		  || (reg_equiv[regno].replacement
 		      && ! rtx_equal_p (XEXP (note, 0),
-					reg_equiv[regno].replacement))))
-	    {
-	      no_equiv (dest, set, NULL);
-	      continue;
+					reg_equiv[regno].replacement)))
+		{
+		  no_equiv (dest, set, NULL);
+		  continue;
+		}
+
+	      list = reg_equiv[regno].init_insns;
+	      for (; list; list = XEXP (list, 1))
+		{
+		  rtx note_tmp, insn_tmp;
+
+		  insn_tmp = XEXP (list, 0);
+		  note_tmp = find_reg_note (insn_tmp, REG_EQUAL, NULL_RTX);
+		  gcc_assert (note_tmp);
+		  if (! rtx_equal_p (XEXP (note, 0), XEXP (note_tmp, 0)))
+		    {
+		      equal_p = false;
+		      break;
+		    }
+		}
+
+	      if (! equal_p)
+		{
+		  no_equiv (dest, set, NULL);
+		  continue;
+		}
 	    }
+
 	  /* Record this insn as initializing this register.  */
 	  reg_equiv[regno].init_insns
 	    = gen_rtx_INSN_LIST (VOIDmode, insn, reg_equiv[regno].init_insns);
@@ -3505,10 +3540,9 @@ update_equiv_regs (void)
 	     a register used only in one basic block from a MEM.  If so, and the
 	     MEM remains unchanged for the life of the register, add a REG_EQUIV
 	     note.  */
-
 	  note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
 
-	  if (note == 0 && REG_BASIC_BLOCK (regno) >= NUM_FIXED_BLOCKS
+	  if (note == NULL_RTX && REG_BASIC_BLOCK (regno) >= NUM_FIXED_BLOCKS
 	      && MEM_P (SET_SRC (set))
 	      && validate_equiv_mem (insn, dest, SET_SRC (set)))
 	    note = set_unique_reg_note (insn, REG_EQUIV, copy_rtx (SET_SRC (set)));