tree: Avoid variable sharing in get_narrower [PR94724]

tree: Avoid variable sharing in get_narrower [PR94724]

On Thu, May 07, 2020 at 02:45:29PM +0200, Thomas Schwinge wrote:
> >>+      for (tree op = win; TREE_CODE (op) == COMPOUND_EXPR;
>
> ..., and new 'op' variable here.
>
> >>+        op = TREE_OPERAND (op, 1))
> >>+     v.safe_push (op);
> >>+      FOR_EACH_VEC_ELT_REVERSE (v, i, op)
> >>+     ret = build2_loc (EXPR_LOCATION (op), COMPOUND_EXPR,
> >>+                       TREE_TYPE (win), TREE_OPERAND (op, 0),
> >>+                       ret);
> >>+      return ret;
> >>     }
> >>   while (TREE_CODE (op) == NOP_EXPR)
> >>     {

There is no reason for the shadowing and op at this point acts as a
temporary and will be overwritten in FOR_EACH_VEC_ELT_REVERSE anyway.
So, we can just s/tree // here.

2020-05-08  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/94724
	* tree.c (get_narrower): Reuse the op temporary instead of
	shadowing it.