re PR middle-end/80533 (Alias analysis of zero length array does not recognize access...

2017-04-27  Richard Biener  <rguenther@suse.de>

	PR middle-end/80533
	* emit-rtl.c (set_mem_attributes_minus_bitpos): When
	stripping ARRAY_REFs from MEM_EXPR make sure we're not
	keeping a reference to a trailing array.

From-SVN: r247327

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 44580fc15e2ed386dc191cf083e6b0622744b0c0..ac9a03c83074bd3c1fa0be11a17716bcc78fe8ee 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-04-27  Richard Biener  <rguenther@suse.de>
+
+       PR middle-end/80533
+       * emit-rtl.c (set_mem_attributes_minus_bitpos): When
+       stripping ARRAY_REFs from MEM_EXPR make sure we're not
+       keeping a reference to a trailing array.
+
 2017-04-27  Richard Biener  <rguenther@suse.de>
 
        PR middle-end/80539

diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index 0d25d4ec17ec7aea4696d3553b094c3c60096d03..d7aba8864beac8c96f7b61c00a6e16b860302c78 100644 (file)
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -1954,7 +1954,10 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int objectp,
          while (TREE_CODE (t2) == ARRAY_REF);
 
          if (DECL_P (t2)
-             || TREE_CODE (t2) == COMPONENT_REF)
+             || (TREE_CODE (t2) == COMPONENT_REF
+                 /* For trailing arrays t2 doesn't have a size that
+                    covers all valid accesses.  */
+                 && ! array_at_struct_end_p (t, false)))
            {
              attrs.expr = t2;
              attrs.offset_known_p = false;