* gcc.pot: Regenerate.

[pf3gnuchains/gcc-fork.git] / gcc / fwprop.c

diff --git a/gcc/fwprop.c b/gcc/fwprop.c
index 32264cd..6e65093 100644 (file)
--- a/gcc/fwprop.c
+++ b/gcc/fwprop.c
@@ -1,5 +1,6 @@
 /* RTL-based forward propagation pass for GNU compiler.
-   Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+   Free Software Foundation, Inc.
    Contributed by Paolo Bonzini and Steven Bosscher.
 
 This file is part of GCC.
@@ -227,7 +228,10 @@ single_def_use_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
 
   process_uses (df_get_artificial_uses (bb_index), DF_REF_AT_TOP);
   process_defs (df_get_artificial_defs (bb_index), DF_REF_AT_TOP);
-  df_simulate_initialize_forwards (bb, local_lr);
+
+  /* We don't call df_simulate_initialize_forwards, as it may overestimate
+     the live registers if there are unused artificial defs.  We prefer
+     liveness to be underestimated.  */
 
   FOR_BB_INSNS (bb, insn)
     if (INSN_P (insn))
@@ -818,17 +822,23 @@ all_uses_available_at (rtx def_insn, rtx target_insn)
     }
   else
     {
+      rtx def_reg = REG_P (SET_DEST (def_set)) ? SET_DEST (def_set) : NULL_RTX;
+
       /* Look at all the uses of DEF_INSN, and see if they are not
         killed between DEF_INSN and TARGET_INSN.  */
       for (use_rec = DF_INSN_INFO_USES (insn_info); *use_rec; use_rec++)
        {
          df_ref use = *use_rec;
+         if (def_reg && rtx_equal_p (DF_REF_REG (use), def_reg))
+           return false;
          if (use_killed_between (use, def_insn, target_insn))
            return false;
        }
       for (use_rec = DF_INSN_INFO_EQ_USES (insn_info); *use_rec; use_rec++)
        {
          df_ref use = *use_rec;
+         if (def_reg && rtx_equal_p (DF_REF_REG (use), def_reg))
+           return false;
          if (use_killed_between (use, def_insn, target_insn))
            return false;
        }
@@ -1039,7 +1049,7 @@ free_load_extend (rtx src, rtx insn)
 {
   rtx reg;
   df_ref *use_vec;
-  df_ref use, def;
+  df_ref use = 0, def;
 
   reg = XEXP (src, 0);
 #ifdef LOAD_EXTEND_OP