PR debug/52001

PR rtl-optimization/52417
* cselib.c (cselib_any_perm_equivs): New variable.
(cselib_reset_table): Check that it's not set when not
preserving constants.
(cselib_add_permanent_equiv): Set it.
(cselib_have_permanent_equivalences): New.
(cselib_init, cselib_finish): Reset it.
* cselib.h (cselib_have_permanent_equivalences): Declare.
* alias.c (get_addr): Restore earlier behavior when there
aren't permanent equivalences.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@184750 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 23 insertions, 9 deletions

diff --git a/gcc/alias.c b/gcc/alias.c
index 4bda40d8836..e9d701f9636 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -1811,20 +1811,34 @@ get_addr (rtx x)
   v = CSELIB_VAL_PTR (x);
   if (v)
     {
-      v = canonical_cselib_val (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) && GET_CODE (l->loc) != VALUE
-	    && !refs_newer_value_p (l->loc, x))
+	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;
-      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 (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;
     }
   return x;
 }