PR c++/53220

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

diff --git a/gcc/alias.c b/gcc/alias.c
index b9b9676..e9d701f 100644 (file)
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -1773,6 +1773,29 @@ base_alias_check (rtx x, rtx y, enum machine_mode x_mode,
   return 1;
 }
 
+/* Callback for for_each_rtx, that returns 1 upon encountering a VALUE
+   whose UID is greater than the int uid that D points to.  */
+
+static int
+refs_newer_value_cb (rtx *x, void *d)
+{
+  if (GET_CODE (*x) == VALUE && CSELIB_VAL_PTR (*x)->uid > *(int *)d)
+    return 1;
+
+  return 0;
+}
+
+/* Return TRUE if EXPR refers to a VALUE whose uid is greater than
+   that of V.  */
+
+static bool
+refs_newer_value_p (rtx expr, rtx v)
+{
+  int minuid = CSELIB_VAL_PTR (v)->uid;
+
+  return for_each_rtx (&expr, refs_newer_value_cb, &minuid);
+}
+
 /* Convert the address X into something we can use.  This is done by returning
    it unchanged unless it is a value; in the latter case we call cselib to get
    a more useful rtx.  */
@@ -1788,12 +1811,32 @@ get_addr (rtx x)
   v = CSELIB_VAL_PTR (x);
   if (v)
     {
+      bool have_equivs = cselib_have_permanent_equivalences ();
+      if (have_equivs)
+       v = canonical_cselib_val (v);
       for (l = v->locs; l; l = l->next)
        if (CONSTANT_P (l->loc))
          return l->loc;
       for (l = v->locs; l; l = l->next)
-       if (!REG_P (l->loc) && !MEM_P (l->loc))
+       if (!REG_P (l->loc) && !MEM_P (l->loc)
+           /* Avoid infinite recursion when potentially dealing with
+              var-tracking artificial equivalences, by skipping the
+              equivalences themselves, and not choosing expressions
+              that refer to newer VALUEs.  */
+           && (!have_equivs
+               || (GET_CODE (l->loc) != VALUE
+                   && !refs_newer_value_p (l->loc, x))))
          return l->loc;
+      if (have_equivs)
+       {
+         for (l = v->locs; l; l = l->next)
+           if (REG_P (l->loc)
+               || (GET_CODE (l->loc) != VALUE
+                   && !refs_newer_value_p (l->loc, x)))
+             return l->loc;
+         /* Return the canonical value.  */
+         return v->val_rtx;
+       }
       if (v->locs)
        return v->locs->loc;
     }
@@ -1873,7 +1916,8 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
        {
          struct elt_loc_list *l = NULL;
          if (CSELIB_VAL_PTR (x))
-           for (l = CSELIB_VAL_PTR (x)->locs; l; l = l->next)
+           for (l = canonical_cselib_val (CSELIB_VAL_PTR (x))->locs;
+                l; l = l->next)
              if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y))
                break;
          if (l)
@@ -1891,7 +1935,8 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
        {
          struct elt_loc_list *l = NULL;
          if (CSELIB_VAL_PTR (y))
-           for (l = CSELIB_VAL_PTR (y)->locs; l; l = l->next)
+           for (l = canonical_cselib_val (CSELIB_VAL_PTR (y))->locs;
+                l; l = l->next)
              if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x))
                break;
          if (l)