loop-invariant.c (replace_uses): New static function.

	* loop-invariant.c (replace_uses): New static function.
	(move_invariant_reg): Use it to ensure we can replace the uses.

From-SVN: r158175

1 files changed, 41 insertions, 22 deletions

diff --git a/gcc/loop-invariant.c b/gcc/loop-invariant.c
index e6c429e..2f38123 100644
--- a/gcc/loop-invariant.c
+++ b/gcc/loop-invariant.c
@@ -1367,6 +1367,32 @@ find_invariants_to_move (bool speed)
     }
 }
 
+/* Replace the uses, reached by the definition of invariant INV, by REG.
+
+   IN_GROUP is nonzero if this is part of a group of changes that must be
+   performed as a group.  In that case, the changes will be stored.  The
+   function `apply_change_group' will validate and apply the changes.  */
+
+static int
+replace_uses (struct invariant *inv, rtx reg, bool in_group)
+{
+  /* Replace the uses we know to be dominated.  It saves work for copy
+     propagation, and also it is necessary so that dependent invariants
+     are computed right.  */
+  if (inv->def)
+    {
+      struct use *use;
+      for (use = inv->def->uses; use; use = use->next)
+	validate_change (use->insn, use->pos, reg, true);
+
+      /* If we aren't part of a larger group, apply the changes now.  */
+      if (!in_group)
+	return apply_change_group ();
+    }
+
+  return 1;
+}
+
 /* Move invariant INVNO out of the LOOP.  Returns true if this succeeds, false
    otherwise.  */
 
@@ -1378,15 +1404,14 @@ move_invariant_reg (struct loop *loop, unsigned invno)
   unsigned i;
   basic_block preheader = loop_preheader_edge (loop)->src;
   rtx reg, set, dest, note;
-  struct use *use;
   bitmap_iterator bi;
-  int regno;
+  int regno = -1;
 
   if (inv->reg)
     return true;
   if (!repr->move)
     return false;
-  regno = -1;
+
   /* If this is a representative of the class of equivalent invariants,
      really move the invariant.  Otherwise just replace its use with
      the register used for the representative.  */
@@ -1402,10 +1427,10 @@ move_invariant_reg (struct loop *loop, unsigned invno)
 	}
 
       /* Move the set out of the loop.  If the set is always executed (we could
-	 omit this condition if we know that the register is unused outside of the
-	 loop, but it does not seem worth finding out) and it has no uses that
-	 would not be dominated by it, we may just move it (TODO).  Otherwise we
-	 need to create a temporary register.  */
+	 omit this condition if we know that the register is unused outside of
+	 the loop, but it does not seem worth finding out) and it has no uses
+	 that would not be dominated by it, we may just move it (TODO).
+	 Otherwise we need to create a temporary register.  */
       set = single_set (inv->insn);
       reg = dest = SET_DEST (set);
       if (GET_CODE (reg) == SUBREG)
@@ -1416,9 +1441,14 @@ move_invariant_reg (struct loop *loop, unsigned invno)
       reg = gen_reg_rtx_and_attrs (dest);
 
       /* Try replacing the destination by a new pseudoregister.  */
-      if (!validate_change (inv->insn, &SET_DEST (set), reg, false))
+      validate_change (inv->insn, &SET_DEST (set), reg, true);
+
+      /* As well as all the dominated uses.  */
+      replace_uses (inv, reg, true);
+
+      /* And validate all the changes.  */
+      if (!apply_change_group ())
 	goto fail;
-      df_insn_rescan (inv->insn);
 
       emit_insn_after (gen_move_insn (dest, reg), inv->insn);
       reorder_insns (inv->insn, inv->insn, BB_END (preheader));
@@ -1441,27 +1471,16 @@ move_invariant_reg (struct loop *loop, unsigned invno)
 	goto fail;
       reg = repr->reg;
       regno = repr->orig_regno;
+      if (!replace_uses (inv, reg, false))
+	goto fail;
       set = single_set (inv->insn);
       emit_insn_after (gen_move_insn (SET_DEST (set), reg), inv->insn);
       delete_insn (inv->insn);
     }
 
-
   inv->reg = reg;
   inv->orig_regno = regno;
 
-  /* Replace the uses we know to be dominated.  It saves work for copy
-     propagation, and also it is necessary so that dependent invariants
-     are computed right.  */
-  if (inv->def)
-    {
-      for (use = inv->def->uses; use; use = use->next)
-	{
-	  *use->pos = reg;
-	  df_insn_rescan (use->insn);
-	}
-    }
-
   return true;
 
 fail: