gcc/

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

diff --git a/gcc/fwprop.c b/gcc/fwprop.c
index 50daed2..d3ed742 100644 (file)
--- a/gcc/fwprop.c
+++ b/gcc/fwprop.c
@@ -1014,24 +1014,54 @@ try_fwprop_subst (df_ref use, rtx *loc, rtx new_rtx, rtx def_insn, bool set_reg_
   return ok;
 }
 
-#ifdef LOAD_EXTEND_OP
-static df_ref
-get_reg_use_in (rtx insn, rtx reg)
+/* For the given single_set INSN, containing SRC known to be a
+   ZERO_EXTEND or SIGN_EXTEND of a register, return true if INSN
+   is redundant due to the register being set by a LOAD_EXTEND_OP
+   load from memory.  */
+
+static bool
+free_load_extend (rtx src, rtx insn)
 {
+  rtx reg;
   df_ref *use_vec;
+  df_ref use, def;
+
+  reg = XEXP (src, 0);
+#ifdef LOAD_EXTEND_OP
+  if (LOAD_EXTEND_OP (GET_MODE (reg)) != GET_CODE (src))
+#endif
+    return false;
 
   for (use_vec = DF_INSN_USES (insn); *use_vec; use_vec++)
     {
-      df_ref use = *use_vec;
+      use = *use_vec;
 
       if (!DF_REF_IS_ARTIFICIAL (use)
          && DF_REF_TYPE (use) == DF_REF_REG_USE
          && DF_REF_REG (use) == reg)
-       return use;
+       break;
+    }
+  if (!use)
+    return false;
+
+  def = get_def_for_use (use);
+  if (!def)
+    return false;
+
+  if (DF_REF_IS_ARTIFICIAL (def))
+    return false;
+
+  if (NONJUMP_INSN_P (DF_REF_INSN (def)))
+    {
+      rtx patt = PATTERN (DF_REF_INSN (def));
+
+      if (GET_CODE (patt) == SET
+         && GET_CODE (SET_SRC (patt)) == MEM
+         && rtx_equal_p (SET_DEST (patt), reg))
+       return true;
     }
-  return NULL;
+  return false;
 }
-#endif
 
 /* If USE is a subreg, see if it can be replaced by a pseudo.  */
 
@@ -1073,26 +1103,13 @@ forward_propagate_subreg (df_ref use, rtx def_insn, rtx def_set)
      be removed due to it matching a LOAD_EXTEND_OP load from memory.  */
   else if (subreg_lowpart_p (use_reg))
     {
-#ifdef LOAD_EXTEND_OP
-      df_ref prev_use, prev_def;
-#endif
       use_insn = DF_REF_INSN (use);
       src = SET_SRC (def_set);
       if ((GET_CODE (src) == ZERO_EXTEND
           || GET_CODE (src) == SIGN_EXTEND)
          && REG_P (XEXP (src, 0))
          && GET_MODE (XEXP (src, 0)) == use_mode
-#ifdef LOAD_EXTEND_OP
-         && !(LOAD_EXTEND_OP (use_mode) == GET_CODE (src)
-              && (prev_use = get_reg_use_in (def_insn, XEXP (src, 0))) != NULL
-              && (prev_def = get_def_for_use (prev_use)) != NULL
-              && !DF_REF_IS_ARTIFICIAL (prev_def)
-              && NONJUMP_INSN_P (DF_REF_INSN (prev_def))
-              && GET_CODE (PATTERN (DF_REF_INSN (prev_def))) == SET
-              && GET_CODE (SET_SRC (PATTERN (DF_REF_INSN (prev_def)))) == MEM
-              && rtx_equal_p (SET_DEST (PATTERN (DF_REF_INSN (prev_def))),
-                              XEXP (src, 0)))
-#endif
+         && !free_load_extend (src, def_insn)
          && all_uses_available_at (def_insn, use_insn))
        return try_fwprop_subst (use, DF_REF_LOC (use), XEXP (src, 0),
                                 def_insn, false);
@@ -1191,7 +1208,7 @@ forward_propagate_and_simplify (df_ref use, rtx def_insn, rtx def_set)
   if (INSN_CODE (use_insn) < 0)
     asm_use = asm_noperands (PATTERN (use_insn));
 
-  if (!use_set && asm_use < 0)
+  if (!use_set && asm_use < 0 && !DEBUG_INSN_P (use_insn))
     return false;
 
   /* Do not propagate into PC, CC0, etc.  */
@@ -1248,6 +1265,11 @@ forward_propagate_and_simplify (df_ref use, rtx def_insn, rtx def_set)
       loc = &SET_DEST (use_set);
       set_reg_equal = false;
     }
+  else if (!use_set)
+    {
+      loc = &INSN_VAR_LOCATION_LOC (use_insn);
+      set_reg_equal = false;
+    }
   else
     {
       rtx note = find_reg_note (use_insn, REG_EQUAL, NULL_RTX);