rs6000: Fix memory leak in rs6000_density_test
Commit Message
rs6000_density_test has an early exit test between a call
to get_loop_body and the corresponding free. This would
lead to a memory leak if the early exit is taken.
Tested on powerpc64le-linux-gnu. It's obvious that moving the
test avoids the leak, but there are multiple ways to write it,
so: OK to install?
Richard
gcc/
* config/rs6000/rs6000.c (rs6000_density_test): Move early
exit test further up the function.
---
gcc/config/rs6000/rs6000.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
Comments
On Thu, Oct 14, 2021 at 9:00 AM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> rs6000_density_test has an early exit test between a call
> to get_loop_body and the corresponding free. This would
> lead to a memory leak if the early exit is taken.
>
> Tested on powerpc64le-linux-gnu. It's obvious that moving the
> test avoids the leak, but there are multiple ways to write it,
> so: OK to install?
Thanks for noticing this and creating a patch.
This is okay.
Thanks, David
>
> Richard
>
>
> gcc/
> * config/rs6000/rs6000.c (rs6000_density_test): Move early
> exit test further up the function.
> ---
> gcc/config/rs6000/rs6000.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index acba4d9f26c..01a95591a5d 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -5289,20 +5289,19 @@ struct rs6000_cost_data
> static void
> rs6000_density_test (rs6000_cost_data *data)
> {
> - struct loop *loop = data->loop_info;
> - basic_block *bbs = get_loop_body (loop);
> - int nbbs = loop->num_nodes;
> - loop_vec_info loop_vinfo = loop_vec_info_for_loop (data->loop_info);
> - int vec_cost = data->cost[vect_body], not_vec_cost = 0;
> - int i, density_pct;
> -
> /* This density test only cares about the cost of vector version of the
> loop, so immediately return if we are passed costing for the scalar
> version (namely computing single scalar iteration cost). */
> if (data->costing_for_scalar)
> return;
>
> - for (i = 0; i < nbbs; i++)
> + struct loop *loop = data->loop_info;
> + basic_block *bbs = get_loop_body (loop);
> + int nbbs = loop->num_nodes;
> + loop_vec_info loop_vinfo = loop_vec_info_for_loop (data->loop_info);
> + int vec_cost = data->cost[vect_body], not_vec_cost = 0;
> +
> + for (int i = 0; i < nbbs; i++)
> {
> basic_block bb = bbs[i];
> gimple_stmt_iterator gsi;
> @@ -5322,7 +5321,7 @@ rs6000_density_test (rs6000_cost_data *data)
> }
>
> free (bbs);
> - density_pct = (vec_cost * 100) / (vec_cost + not_vec_cost);
> + int density_pct = (vec_cost * 100) / (vec_cost + not_vec_cost);
>
> if (density_pct > rs6000_density_pct_threshold
> && vec_cost + not_vec_cost > rs6000_density_size_threshold)
@@ -5289,20 +5289,19 @@ struct rs6000_cost_data
static void
rs6000_density_test (rs6000_cost_data *data)
{
- struct loop *loop = data->loop_info;
- basic_block *bbs = get_loop_body (loop);
- int nbbs = loop->num_nodes;
- loop_vec_info loop_vinfo = loop_vec_info_for_loop (data->loop_info);
- int vec_cost = data->cost[vect_body], not_vec_cost = 0;
- int i, density_pct;
-
/* This density test only cares about the cost of vector version of the
loop, so immediately return if we are passed costing for the scalar
version (namely computing single scalar iteration cost). */
if (data->costing_for_scalar)
return;
- for (i = 0; i < nbbs; i++)
+ struct loop *loop = data->loop_info;
+ basic_block *bbs = get_loop_body (loop);
+ int nbbs = loop->num_nodes;
+ loop_vec_info loop_vinfo = loop_vec_info_for_loop (data->loop_info);
+ int vec_cost = data->cost[vect_body], not_vec_cost = 0;
+
+ for (int i = 0; i < nbbs; i++)
{
basic_block bb = bbs[i];
gimple_stmt_iterator gsi;
@@ -5322,7 +5321,7 @@ rs6000_density_test (rs6000_cost_data *data)
}
free (bbs);
- density_pct = (vec_cost * 100) / (vec_cost + not_vec_cost);
+ int density_pct = (vec_cost * 100) / (vec_cost + not_vec_cost);
if (density_pct > rs6000_density_pct_threshold
&& vec_cost + not_vec_cost > rs6000_density_size_threshold)