re PR rtl-optimization/31944 (Endless loop while building a 64-bit 2.6.20 kernel)

	PR rtl-optimization/31944
	* cse.c (remove_pseudo_from_table): New function.
	(merge_equiv_classes): Use above function to remove pseudo-registers.
	(invalidate): Likewise.

From-SVN: r131522

1 files changed, 20 insertions, 10 deletions

diff --git a/gcc/cse.c b/gcc/cse.c
index 09f80fe..f6660e4 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -554,7 +554,8 @@ static void delete_reg_equiv (unsigned int);
 static int mention_regs (rtx);
 static int insert_regs (rtx, struct table_elt *, int);
 static void remove_from_table (struct table_elt *, unsigned);
-static struct table_elt *lookup	(rtx, unsigned, enum machine_mode);
+static void remove_pseudo_from_table (rtx, unsigned);
+static struct table_elt *lookup (rtx, unsigned, enum machine_mode);
 static struct table_elt *lookup_for_remove (rtx, unsigned, enum machine_mode);
 static rtx lookup_as_function (rtx, enum rtx_code);
 static struct table_elt *insert (rtx, struct table_elt *, unsigned,
@@ -1288,6 +1289,19 @@ remove_from_table (struct table_elt *elt, unsigned int hash)
   free_element_chain = elt;
 }
 
+/* Same as above, but X is a pseudo-register.  */
+
+static void
+remove_pseudo_from_table (rtx x, unsigned int hash)
+{
+  struct table_elt *elt;
+
+  /* Because a pseudo-register can be referenced in more than one
+     mode, we might have to remove more than one table entry.  */
+  while ((elt = lookup_for_remove (x, hash, VOIDmode)))
+    remove_from_table (elt, hash);
+}
+
 /* Look up X in the hash table and return its table element,
    or 0 if X is not in the table.
 
@@ -1605,7 +1619,10 @@ merge_equiv_classes (struct table_elt *class1, struct table_elt *class2)
 	      delete_reg_equiv (REGNO (exp));
 	    }
 
-	  remove_from_table (elt, hash);
+	  if (REG_P (exp) && REGNO (exp) >= FIRST_PSEUDO_REGISTER)
+	    remove_pseudo_from_table (exp, hash);
+	  else
+	    remove_from_table (elt, hash);
 
 	  if (insert_regs (exp, class1, 0) || need_rehash)
 	    {
@@ -1701,14 +1718,7 @@ invalidate (rtx x, enum machine_mode full_mode)
 	SUBREG_TICKED (regno) = -1;
 
 	if (regno >= FIRST_PSEUDO_REGISTER)
-	  {
-	    /* Because a register can be referenced in more than one mode,
-	       we might have to remove more than one table entry.  */
-	    struct table_elt *elt;
-
-	    while ((elt = lookup_for_remove (x, hash, GET_MODE (x))))
-	      remove_from_table (elt, hash);
-	  }
+	  remove_pseudo_from_table (x, hash);
 	else
 	  {
 	    HOST_WIDE_INT in_table