> Index: tree-ssa-loop-ivopts.c
> ===================================================================
> --- tree-ssa-loop-ivopts.c (revision 158148)
> +++ tree-ssa-loop-ivopts.c (working copy)
> @@ -1546,6 +1546,9 @@ may_be_unaligned_p (tree ref, tree step)
>
> || bitpos % BITS_PER_UNIT != 0)
>
> return true;
>
> + if (toffset && !constant_multiple_of (toffset, al, &mul))
> + return true;
> +
> if (!constant_multiple_of (step, al, &mul))
> return true;
> }
constant_multiple_of is too restrictive though, something like:
Index: tree-ssa-loop-ivopts.c
===================================================================
--- tree-ssa-loop-ivopts.c (revision 158148)
+++ tree-ssa-loop-ivopts.c (working copy)
@@ -1537,16 +1537,18 @@ may_be_unaligned_p (tree ref, tree step)
if (mode != BLKmode)
{
- double_int mul;
- tree al = build_int_cst (TREE_TYPE (step),
- GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT);
+ unsigned mode_align = GET_MODE_ALIGNMENT (mode);
- if (base_align < GET_MODE_ALIGNMENT (mode)
- || bitpos % GET_MODE_ALIGNMENT (mode) != 0
- || bitpos % BITS_PER_UNIT != 0)
+ if (base_align < mode_align
+ || (bitpos % mode_align) != 0
+ || (bitpos % BITS_PER_UNIT) != 0)
return true;
- if (!constant_multiple_of (step, al, &mul))
+ if (toffset
+ && (highest_pow2_factor (toffset) * BITS_PER_UNIT) < mode_align)
+ return true;
+
+ if ((highest_pow2_factor (step) * BITS_PER_UNIT) < mode_align)
return true;
}
--
Eric Botcazou
