2012-07-20 Richard Guenther <rguenther@suse.de>

	* builtins.c (get_object_alignment_2): Correct offset handling
	when using type alignment of a MEM_REF kind base.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@189704 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 16cb34d..2c4c273 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-07-20  Richard Guenther  <rguenther@suse.de>
+
+       * builtins.c (get_object_alignment_2): Correct offset handling
+       when using type alignment of a MEM_REF kind base.
+
 2012-07-20  Kirill Yukhin  <kirill.yukhin@intel.com>
 
        PR target/53877

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 4fb3d53..a8318e8 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -346,12 +346,10 @@ get_object_alignment_2 (tree exp, unsigned int *alignp,
 
       known_alignment
        = get_pointer_alignment_1 (addr, &ptr_align, &ptr_bitpos);
-      bitpos += ptr_bitpos;
       align = MAX (ptr_align, align);
 
-      if (TREE_CODE (exp) == MEM_REF
-         || TREE_CODE (exp) == TARGET_MEM_REF)
-       bitpos += mem_ref_offset (exp).low * BITS_PER_UNIT;
+      /* The alignment of the pointer operand in a TARGET_MEM_REF
+        has to take the variable offset parts into account.  */
       if (TREE_CODE (exp) == TARGET_MEM_REF)
        {
          if (TMR_INDEX (exp))
@@ -369,9 +367,19 @@ get_object_alignment_2 (tree exp, unsigned int *alignp,
       /* When EXP is an actual memory reference then we can use
         TYPE_ALIGN of a pointer indirection to derive alignment.
         Do so only if get_pointer_alignment_1 did not reveal absolute
-        alignment knowledge.  */
-      if (!addr_p && !known_alignment)
-       align = MAX (TYPE_ALIGN (TREE_TYPE (exp)), align);
+        alignment knowledge and if using that alignment would
+        improve the situation.  */
+      if (!addr_p && !known_alignment
+         && TYPE_ALIGN (TREE_TYPE (exp)) > align)
+       align = TYPE_ALIGN (TREE_TYPE (exp));
+      else
+       {
+         /* Else adjust bitpos accordingly.  */
+         bitpos += ptr_bitpos;
+         if (TREE_CODE (exp) == MEM_REF
+             || TREE_CODE (exp) == TARGET_MEM_REF)
+           bitpos += mem_ref_offset (exp).low * BITS_PER_UNIT;
+       }
     }
   else if (TREE_CODE (exp) == STRING_CST)
     {