2002-05-20 David S. Miller <davem@redhat.com>

	* cselib.c (max_value_regs): New.
	(cselib_lookup, cselib_invalidate_regno): Initialize it when
	adding new entries to the REG_VALUES table and we are dealing with
	a hard register.
	(clear_table): Initialize it.
	(cselib_invalidate_regno): Use it to determine which hard
	registers to scan when mode is not VOIDmode.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@53684 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 36 insertions, 3 deletions

diff --git a/gcc/cselib.c b/gcc/cselib.c
index 0eb17b8a836..b0348fbc462 100644
--- a/gcc/cselib.c
+++ b/gcc/cselib.c
@@ -104,6 +104,10 @@ static int n_useless_values;
 static varray_type reg_values;
 #define REG_VALUES(I) VARRAY_ELT_LIST (reg_values, (I))
 
+/* The largest number of hard regs used by any entry added to the
+   REG_VALUES table.  Cleared on each clear_table() invocation.   */
+static unsigned int max_value_regs;
+
 /* Here the set of indices I with REG_VALUES(I) != 0 is saved.  This is used
    in clear_table() for fast emptying.  */
 static varray_type used_regs;
@@ -227,6 +231,8 @@ clear_table (clear_all)
     for (i = 0; i < VARRAY_ACTIVE_SIZE (used_regs); i++)
       REG_VALUES (VARRAY_UINT (used_regs, i)) = 0;
 
+  max_value_regs = 0;
+
   VARRAY_POP_ALL (used_regs);
 
   htab_empty (hash_table);
@@ -897,6 +903,14 @@ cselib_lookup (x, mode, create)
       if (! create)
 	return 0;
 
+      if (i < FIRST_PSEUDO_REGISTER)
+	{
+	  unsigned int n = HARD_REGNO_NREGS (i, mode);
+
+	  if (n > max_value_regs)
+	    max_value_regs = n;
+	}
+
       e = new_cselib_val (++next_unknown_value, GET_MODE (x));
       e->locs = new_elt_loc_list (e->locs, x);
       if (REG_VALUES (i) == 0)
@@ -957,11 +971,22 @@ cselib_invalidate_regno (regno, mode)
      pseudos, only REGNO is affected.  For hard regs, we must take MODE
      into account, and we must also invalidate lower register numbers
      if they contain values that overlap REGNO.  */
-  endregno = regno + 1;
   if (regno < FIRST_PSEUDO_REGISTER && mode != VOIDmode) 
-    endregno = regno + HARD_REGNO_NREGS (regno, mode);
+    {
+      if (regno < max_value_regs)
+	i = 0;
+      else
+	i = regno - max_value_regs;
 
-  for (i = 0; i < endregno; i++)
+      endregno = regno + HARD_REGNO_NREGS (regno, mode);
+    }
+  else
+    {
+      i = regno;
+      endregno = regno + 1;
+    }
+
+  for (; i < endregno; i++)
     {
       struct elt_list **l = &REG_VALUES (i);
 
@@ -1171,6 +1196,14 @@ cselib_record_set (dest, src_elt, dest_addr_elt)
       if (REG_VALUES (dreg) == 0)
         VARRAY_PUSH_UINT (used_regs, dreg);
 
+      if (dreg < FIRST_PSEUDO_REGISTER)
+	{
+	  unsigned int n = HARD_REGNO_NREGS (dreg, GET_MODE (dest));
+
+	  if (n > max_value_regs)
+	    max_value_regs = n;
+	}
+
       REG_VALUES (dreg) = new_elt_list (REG_VALUES (dreg), src_elt);
       if (src_elt->locs == 0)
 	n_useless_values--;