2015-02-27 Richard Biener <rguenther@suse.de>

	PR middle-end/63175
	* builtins.c (get_object_alignment_2): Make sure to re-apply
	the ANDed mask after recursing to its operand gets us a new
	misalignment bit position.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@221043 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e4346a0..7763c88 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2015-02-27  Richard Biener  <rguenther@suse.de>
+
+       PR middle-end/63175
+       * builtins.c (get_object_alignment_2): Make sure to re-apply
+       the ANDed mask after recursing to its operand gets us a new
+       misalignment bit position.
+
 2015-02-26  Jan Hubicka  <hubicka@ucw.cz>
            Martin Liska  <mliska@suse.cz>
 

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 8f3c0bc..fb871e6 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -359,13 +359,15 @@ get_object_alignment_2 (tree exp, unsigned int *alignp,
       tree addr = TREE_OPERAND (exp, 0);
       unsigned ptr_align;
       unsigned HOST_WIDE_INT ptr_bitpos;
+      unsigned HOST_WIDE_INT ptr_bitmask = ~0;
 
+      /* If the address is explicitely aligned, handle that.  */
       if (TREE_CODE (addr) == BIT_AND_EXPR
          && TREE_CODE (TREE_OPERAND (addr, 1)) == INTEGER_CST)
        {
-         align = (TREE_INT_CST_LOW (TREE_OPERAND (addr, 1))
-                   & -TREE_INT_CST_LOW (TREE_OPERAND (addr, 1)));
-         align *= BITS_PER_UNIT;
+         ptr_bitmask = TREE_INT_CST_LOW (TREE_OPERAND (addr, 1));
+         ptr_bitmask *= BITS_PER_UNIT;
+         align = ptr_bitmask & -ptr_bitmask;
          addr = TREE_OPERAND (addr, 0);
        }
 
@@ -373,6 +375,9 @@ get_object_alignment_2 (tree exp, unsigned int *alignp,
        = get_pointer_alignment_1 (addr, &ptr_align, &ptr_bitpos);
       align = MAX (ptr_align, align);
 
+      /* Re-apply explicit alignment to the bitpos.  */
+      ptr_bitpos &= ptr_bitmask;
+
       /* 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)