2010-04-07 Richard Guenther <rguenther@suse.de>

	PR middle-end/42617
	* alias.c (ao_ref_from_mem): Without MEM_OFFSET or MEM_SIZE
	preserve points-to related information.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@158046 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d41b7d5..4c9b75a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2010-04-07  Richard Guenther  <rguenther@suse.de>
 
        PR middle-end/42617
+       * alias.c (ao_ref_from_mem): Without MEM_OFFSET or MEM_SIZE
+       preserve points-to related information.
+
+2010-04-07  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/42617
        * emit-rtl.c (set_mem_attributes_minus_bitpos): Do not
        discard plain indirect references.
        * fold-const.c (operand_equal_p): Guard against NULL_TREE

diff --git a/gcc/alias.c b/gcc/alias.c
index cd7e2a0..19a8292 100644 (file)
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -265,11 +265,6 @@ ao_ref_from_mem (ao_ref *ref, const_rtx mem)
   if (!expr)
     return false;
 
-  /* If MEM_OFFSET or MEM_SIZE are NULL punt.  */
-  if (!MEM_OFFSET (mem)
-      || !MEM_SIZE (mem))
-    return false;
-
   ao_ref_init (ref, expr);
 
   /* Get the base of the reference and see if we have to reject or
@@ -278,17 +273,17 @@ ao_ref_from_mem (ao_ref *ref, const_rtx mem)
   if (base == NULL_TREE)
     return false;
 
+  /* The tree oracle doesn't like to have these.  */
+  if (TREE_CODE (base) == FUNCTION_DECL
+      || TREE_CODE (base) == LABEL_DECL)
+    return false;
+
   /* If this is a pointer dereference of a non-SSA_NAME punt.
      ???  We could replace it with a pointer to anything.  */
   if (INDIRECT_REF_P (base)
       && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME)
     return false;
 
-  /* The tree oracle doesn't like to have these.  */
-  if (TREE_CODE (base) == FUNCTION_DECL
-      || TREE_CODE (base) == LABEL_DECL)
-    return false;
-
   /* If this is a reference based on a partitioned decl replace the
      base with an INDIRECT_REF of the pointer representative we
      created during stack slot partitioning.  */
@@ -307,6 +302,18 @@ ao_ref_from_mem (ao_ref *ref, const_rtx mem)
 
   ref->ref_alias_set = MEM_ALIAS_SET (mem);
 
+  /* If MEM_OFFSET or MEM_SIZE are NULL we have to punt.
+     Keep points-to related information though.  */
+  if (!MEM_OFFSET (mem)
+      || !MEM_SIZE (mem))
+    {
+      ref->ref = NULL_TREE;
+      ref->offset = 0;
+      ref->size = -1;
+      ref->max_size = -1;
+      return true;
+    }
+
   /* If the base decl is a parameter we can have negative MEM_OFFSET in
      case of promoted subregs on bigendian targets.  Trust the MEM_EXPR
      here.  */