regrename.c (mode_change_ok): New.

        * regrename.c (mode_change_ok): New.
        (find_oldest_value_reg): Use it.

From-SVN: r48029

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 623adb9aa6e933fe24fcd639d844d5f15fa8ba11..2e4f175d1dbc35838996defd51274af49ad76dd5 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2001-12-14  Richard Henderson  <rth@redhat.com>
+
+       * regrename.c (mode_change_ok): New.
+       (find_oldest_value_reg): Use it.
+
 2001-12-14  Richard Henderson  <rth@redhat.com>
 
        * regrename.c (struct value_data): Add max_value_regs.

diff --git a/gcc/regrename.c b/gcc/regrename.c
index 4683de40620c4d6039e49f6368b471a6bd0a82f8..ddef8378eee3bf9153ac0e30f42706a3a5f552b5 100644 (file)
--- a/gcc/regrename.c
+++ b/gcc/regrename.c
@@ -996,6 +996,8 @@ static void kill_clobbered_value PARAMS ((rtx, rtx, void *));
 static void kill_set_value PARAMS ((rtx, rtx, void *));
 static int kill_autoinc_value PARAMS ((rtx *, void *));
 static void copy_value PARAMS ((rtx, rtx, struct value_data *));
+static bool mode_change_ok PARAMS ((enum machine_mode, enum machine_mode,
+                                   unsigned int));
 static rtx find_oldest_value_reg PARAMS ((enum reg_class, unsigned int,
                                            enum machine_mode,
                                            struct value_data *));
@@ -1212,6 +1214,25 @@ copy_value (dest, src, vd)
 #endif
 }
 
+/* Return true if a mode change from ORIG to NEW is allowed for REGNO.  */
+
+static bool
+mode_change_ok (orig_mode, new_mode, regno)
+     enum machine_mode orig_mode, new_mode;
+     unsigned int regno;
+{
+  if (GET_MODE_SIZE (orig_mode) < GET_MODE_SIZE (new_mode))
+    return false;
+
+#ifdef CLASS_CANNOT_CHANGE_MODE
+  if (TEST_HARD_REG_BIT (reg_class_contents[CLASS_CANNOT_CHANGE_MODE], regno)
+      && CLASS_CANNOT_CHANGE_MODE_P (orig_mode, new_mode))
+    return false;
+#endif
+
+  return true;
+}
+
 /* Find the oldest copy of the value contained in REGNO that is in
    register class CLASS and has mode MODE.  If found, return an rtx
    of that oldest register, otherwise return NULL.  */
@@ -1226,8 +1247,9 @@ find_oldest_value_reg (class, regno, mode, vd)
   unsigned int i;
 
   for (i = vd->e[regno].oldest_regno; i != regno; i = vd->e[i].next_regno)
-    if (vd->e[i].mode == mode
-       && TEST_HARD_REG_BIT (reg_class_contents[class], i))
+    if (TEST_HARD_REG_BIT (reg_class_contents[class], i)
+       && (vd->e[i].mode == mode
+           || mode_change_ok (vd->e[i].mode, mode, regno)))
       return gen_rtx_REG (mode, i);
 
   return NULL_RTX;