On Tue, May 31, 2016 at 3:00 PM, Patrick Palka <patr...@parcs.ath.cx> wrote:
> Some code paths of cp_fold return early instead of falling through to
> the end of the function and so in these cases we fail to cache the
> return value of the function into the fold_cache.
>
> This patch splits cp_fold into two functions, with the wrapper function
> being responsible for caching the output of the worker function. Does
> this look OK to commit after bootstrap and regtest?
On second thought this change is not really beneficial since all the
cases where we return early from cp_fold are very cheap to re-compute
so it would be pointless to cache them.
>
> gcc/cp/ChangeLog:
>
> * cp-gimplify.c (cp_fold_1): Split out from ...
> (cp_fold): ... here. Cache the output of cp_fold_1 into the
> fold_cache.
> ---
> gcc/cp/cp-gimplify.c | 33 +++++++++++++++++++++++----------
> 1 file changed, 23 insertions(+), 10 deletions(-)
>
> diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
> index 7b63db4..aaf5f48 100644
> --- a/gcc/cp/cp-gimplify.c
> +++ b/gcc/cp/cp-gimplify.c
> @@ -39,6 +39,7 @@ along with GCC; see the file COPYING3. If not see
> static tree cp_genericize_r (tree *, int *, void *);
> static tree cp_fold_r (tree *, int *, void *);
> static void cp_genericize_tree (tree*);
> +static tree cp_fold_1 (tree);
> static tree cp_fold (tree);
>
> /* Local declarations. */
> @@ -1934,11 +1935,7 @@ clear_fold_cache (void)
> static tree
> cp_fold (tree x)
> {
> - tree op0, op1, op2, op3;
> - tree org_x = x, r = NULL_TREE;
> - enum tree_code code;
> - location_t loc;
> - bool rval_ops = true;
> + tree org_x = x;
>
> if (!x || x == error_mark_node)
> return x;
> @@ -1957,6 +1954,27 @@ cp_fold (tree x)
> if (tree *cached = fold_cache->get (x))
> return *cached;
>
> + x = cp_fold_1 (x);
> +
> + fold_cache->put (org_x, x);
> + /* Prevent that we try to fold an already folded result again. */
> + if (x != org_x)
> + fold_cache->put (x, x);
> +
> + return x;
> +}
> +
> +/* Worker function for cp_fold. */
> +
> +static tree
> +cp_fold_1 (tree x)
> +{
> + tree op0, op1, op2, op3;
> + tree org_x = x, r = NULL_TREE;
> + enum tree_code code;
> + location_t loc;
> + bool rval_ops = true;
> +
> code = TREE_CODE (x);
> switch (code)
> {
> @@ -2319,11 +2337,6 @@ cp_fold (tree x)
> return org_x;
> }
>
> - fold_cache->put (org_x, x);
> - /* Prevent that we try to fold an already folded result again. */
> - if (x != org_x)
> - fold_cache->put (x, x);
> -
> return x;
> }
>
> --
> 2.9.0.rc0.29.gabd6606
>
