| Message ID | 20211018042438.803964-1-siddhesh@gotplt.org |
|---|---|
| State | New |
| Headers | show |
| Series | tree-object-size: Avoid unnecessary processing of __builtin_object_size | expand |
On Mon, Oct 18, 2021 at 6:25 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote: > > This is a minor cleanup to bail out early if the result of > __builtin_object_size is not assigned to anything and avoid initializing > the object size arrays. OK. Thanks, Richard. > gcc/ChangeLog: > > * tree-object-size (object_sizes_execute): Consolidate LHS null > check and do it early. > > Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org> > --- > gcc/tree-object-size.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c > index 6a4dc724f34..46a976dfe10 100644 > --- a/gcc/tree-object-size.c > +++ b/gcc/tree-object-size.c > @@ -1298,6 +1298,10 @@ object_sizes_execute (function *fun, bool insert_min_max_p) > if (!gimple_call_builtin_p (call, BUILT_IN_OBJECT_SIZE)) > continue; > > + tree lhs = gimple_call_lhs (call); > + if (!lhs) > + continue; > + > init_object_sizes (); > > /* If insert_min_max_p, only attempt to fold > @@ -1312,11 +1316,9 @@ object_sizes_execute (function *fun, bool insert_min_max_p) > { > unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); > tree ptr = gimple_call_arg (call, 0); > - tree lhs = gimple_call_lhs (call); > if ((object_size_type == 1 || object_size_type == 3) > && (TREE_CODE (ptr) == ADDR_EXPR > - || TREE_CODE (ptr) == SSA_NAME) > - && lhs) > + || TREE_CODE (ptr) == SSA_NAME)) > { > tree type = TREE_TYPE (lhs); > unsigned HOST_WIDE_INT bytes; > @@ -1339,10 +1341,6 @@ object_sizes_execute (function *fun, bool insert_min_max_p) > continue; > } > > - tree lhs = gimple_call_lhs (call); > - if (!lhs) > - continue; > - > result = gimple_fold_stmt_to_constant (call, do_valueize); > if (!result) > { > -- > 2.31.1 >
On Mon, Oct 18, 2021 at 11:57:19AM +0200, Richard Biener via Gcc-patches wrote: > On Mon, Oct 18, 2021 at 6:25 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote: > > > > This is a minor cleanup to bail out early if the result of > > __builtin_object_size is not assigned to anything and avoid initializing > > the object size arrays. > > OK. Yeah, fortunately we have expansion for __builtin_object_size so even if the user tries hard to avoid DCE of the builtin with no LHS through -fno-tree-dce etc., it shouldn't ICE but expand to -1, 0 or __builtin_trap () depending on the arguments it had. > > gcc/ChangeLog: > > > > * tree-object-size (object_sizes_execute): Consolidate LHS null > > check and do it early. > > > > Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org> Jakub
diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c index 6a4dc724f34..46a976dfe10 100644 --- a/gcc/tree-object-size.c +++ b/gcc/tree-object-size.c @@ -1298,6 +1298,10 @@ object_sizes_execute (function *fun, bool insert_min_max_p) if (!gimple_call_builtin_p (call, BUILT_IN_OBJECT_SIZE)) continue; + tree lhs = gimple_call_lhs (call); + if (!lhs) + continue; + init_object_sizes (); /* If insert_min_max_p, only attempt to fold @@ -1312,11 +1316,9 @@ object_sizes_execute (function *fun, bool insert_min_max_p) { unsigned HOST_WIDE_INT object_size_type = tree_to_uhwi (ost); tree ptr = gimple_call_arg (call, 0); - tree lhs = gimple_call_lhs (call); if ((object_size_type == 1 || object_size_type == 3) && (TREE_CODE (ptr) == ADDR_EXPR - || TREE_CODE (ptr) == SSA_NAME) - && lhs) + || TREE_CODE (ptr) == SSA_NAME)) { tree type = TREE_TYPE (lhs); unsigned HOST_WIDE_INT bytes; @@ -1339,10 +1341,6 @@ object_sizes_execute (function *fun, bool insert_min_max_p) continue; } - tree lhs = gimple_call_lhs (call); - if (!lhs) - continue; - result = gimple_fold_stmt_to_constant (call, do_valueize); if (!result) {
This is a minor cleanup to bail out early if the result of __builtin_object_size is not assigned to anything and avoid initializing the object size arrays. gcc/ChangeLog: * tree-object-size (object_sizes_execute): Consolidate LHS null check and do it early. Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org> --- gcc/tree-object-size.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)