* [C++ PATCH] Partial fix for a recent regression (PR c++/90947)
@ 2019-10-22 15:20 Jakub Jelinek
2019-10-29 20:26 ` Jason Merrill
0 siblings, 1 reply; 4+ messages in thread
From: Jakub Jelinek @ 2019-10-22 15:20 UTC (permalink / raw)
To: Jason Merrill, Martin Sebor; +Cc: gcc-patches
Hi!
The following patch is just a partial fix for a regression introduced
in the PR90947 changes, the testcase is fixed for just C++17/20.
type_initializer_zero_p has been added to the generic code, supposedly
because similar initializer_zerop is in generic code too, but that
means it has a hand-written copy of next_initializable_field which can't
do exactly what next_initializable_field does.
The following patch moves it into the C++ FE which is the only user of that
function and uses next_initializable_field in there.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
I'm afraid I'm lost on how to fix the C++11/14 case, the object
being initialized has std::atomic<int> type, which doesn't have any
direct non-static data members, and has std::__atomic_base<int> as base
class that has some field. The only FIELD_DECL in std::atomic<int>
is DECL_ARTIFICIAL field for the base class, so next_initializable_field
or the hand-written variant thereof doesn't find any initializable fields
for 11/14. The initializer is initializer list { {1} } and the function
just returns true if it doesn't find any initializable fields, so in the end
we misoptimize it as { {0} }.
2019-10-22 Jakub Jelinek <jakub@redhat.com>
PR c++/90947
* tree.h (type_initializer_zero_p): Remove.
* tree.c (type_initializer_zero_p): Remove.
cp/
* cp-tree.h (type_initializer_zero_p): Declare.
* decl.c (reshape_init_array_1): Formatting fix.
* tree.c (type_initializer_zero_p): New function. Moved from
../tree.c, use next_initializable_field, formatting fix.
--- gcc/tree.h.jj 2019-09-20 12:25:13.737920929 +0200
+++ gcc/tree.h 2019-10-22 10:07:26.411826804 +0200
@@ -4690,12 +4690,6 @@ extern tree first_field (const_tree);
extern bool initializer_zerop (const_tree, bool * = NULL);
extern bool initializer_each_zero_or_onep (const_tree);
-/* Analogous to initializer_zerop but also examines the type for
- which the initializer is being used. Unlike initializer_zerop,
- considers empty strings to be zero initializers for arrays and
- non-zero for pointers. */
-extern bool type_initializer_zero_p (tree, tree);
-
extern wide_int vector_cst_int_elt (const_tree, unsigned int);
extern tree vector_cst_elt (const_tree, unsigned int);
--- gcc/tree.c.jj 2019-10-19 09:22:14.830893404 +0200
+++ gcc/tree.c 2019-10-22 10:08:36.501748481 +0200
@@ -11396,73 +11396,6 @@ initializer_each_zero_or_onep (const_tre
}
}
-/* Given an initializer INIT for a TYPE, return true if INIT is zero
- so that it can be replaced by value initialization. This function
- distinguishes betwen empty strings as initializers for arrays and
- for pointers (which make it return false). */
-
-bool
-type_initializer_zero_p (tree type, tree init)
-{
- if (type == error_mark_node || init == error_mark_node)
- return false;
-
- STRIP_NOPS (init);
-
- if (POINTER_TYPE_P (type))
- return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
-
- if (TREE_CODE (init) != CONSTRUCTOR)
- return initializer_zerop (init);
-
- if (TREE_CODE (type) == ARRAY_TYPE)
- {
- tree elt_type = TREE_TYPE (type);
- elt_type = TYPE_MAIN_VARIANT (elt_type);
- if (elt_type == char_type_node)
- return initializer_zerop (init);
-
- tree elt_init;
- unsigned HOST_WIDE_INT i;
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
- if (!type_initializer_zero_p (elt_type, elt_init))
- return false;
- return true;
- }
-
- if (TREE_CODE (type) != RECORD_TYPE)
- return initializer_zerop (init);
-
- tree fld = TYPE_FIELDS (type);
-
- tree fld_init;
- unsigned HOST_WIDE_INT i;
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
- {
- /* Advance to the next member, skipping over everything that
- canot be initialized (including unnamed bit-fields). */
- while (TREE_CODE (fld) != FIELD_DECL
- || DECL_ARTIFICIAL (fld)
- || (DECL_BIT_FIELD (fld) && !DECL_NAME (fld)))
- {
- fld = DECL_CHAIN (fld);
- if (!fld)
- return true;
- continue;
- }
-
- tree fldtype = TREE_TYPE (fld);
- if (!type_initializer_zero_p (fldtype, fld_init))
- return false;
-
- fld = DECL_CHAIN (fld);
- if (!fld)
- break;
- }
-
- return true;
-}
-
/* Check if vector VEC consists of all the equal elements and
that the number of elements corresponds to the type of VEC.
The function returns first element of the vector
--- gcc/cp/cp-tree.h.jj 2019-10-22 08:15:53.810775827 +0200
+++ gcc/cp/cp-tree.h 2019-10-22 10:10:57.265582861 +0200
@@ -7379,6 +7379,11 @@ extern tree cxx_copy_lang_qualifiers (c
extern void cxx_print_statistics (void);
extern bool maybe_warn_zero_as_null_pointer_constant (tree, location_t);
+/* Analogous to initializer_zerop but also examines the type for
+ which the initializer is being used. Unlike initializer_zerop,
+ considers empty strings to be zero initializers for arrays and
+ non-zero for pointers. */
+extern bool type_initializer_zero_p (tree, tree);
/* in ptree.c */
extern void cxx_print_xnode (FILE *, tree, int);
--- gcc/cp/decl.c.jj 2019-10-22 08:57:12.913654620 +0200
+++ gcc/cp/decl.c 2019-10-22 10:13:39.038094034 +0200
@@ -5982,9 +5982,8 @@ reshape_init_array_1 (tree elt_type, tre
/* Pointers initialized to strings must be treated as non-zero
even if the string is empty. */
tree init_type = TREE_TYPE (elt_init);
- if ((POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)))
- last_nonzero = index;
- else if (!type_initializer_zero_p (elt_type, elt_init))
+ if (POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)
+ || !type_initializer_zero_p (elt_type, elt_init))
last_nonzero = index;
/* This can happen with an invalid initializer (c++/54501). */
--- gcc/cp/tree.c.jj 2019-10-19 09:22:16.594866462 +0200
+++ gcc/cp/tree.c 2019-10-22 10:10:29.151015397 +0200
@@ -5527,6 +5527,65 @@ maybe_warn_zero_as_null_pointer_constant
return false;
}
\f
+/* Given an initializer INIT for a TYPE, return true if INIT is zero
+ so that it can be replaced by value initialization. This function
+ distinguishes betwen empty strings as initializers for arrays and
+ for pointers (which make it return false). */
+
+bool
+type_initializer_zero_p (tree type, tree init)
+{
+ if (type == error_mark_node || init == error_mark_node)
+ return false;
+
+ STRIP_NOPS (init);
+
+ if (POINTER_TYPE_P (type))
+ return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
+
+ if (TREE_CODE (init) != CONSTRUCTOR)
+ return initializer_zerop (init);
+
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ tree elt_type = TREE_TYPE (type);
+ elt_type = TYPE_MAIN_VARIANT (elt_type);
+ if (elt_type == char_type_node)
+ return initializer_zerop (init);
+
+ tree elt_init;
+ unsigned HOST_WIDE_INT i;
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
+ if (!type_initializer_zero_p (elt_type, elt_init))
+ return false;
+ return true;
+ }
+
+ if (TREE_CODE (type) != RECORD_TYPE)
+ return initializer_zerop (init);
+
+ tree fld = TYPE_FIELDS (type);
+
+ tree fld_init;
+ unsigned HOST_WIDE_INT i;
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
+ {
+ fld = next_initializable_field (fld);
+ if (!fld)
+ return true;
+
+ tree fldtype = TREE_TYPE (fld);
+ if (!type_initializer_zero_p (fldtype, fld_init))
+ return false;
+
+ fld = DECL_CHAIN (fld);
+ if (!fld)
+ break;
+ }
+
+ return true;
+}
+\f
#if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
/* Complain that some language-specific thing hanging off a tree
node has been accessed improperly. */
Jakub
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [C++ PATCH] Partial fix for a recent regression (PR c++/90947)
2019-10-22 15:20 [C++ PATCH] Partial fix for a recent regression (PR c++/90947) Jakub Jelinek
@ 2019-10-29 20:26 ` Jason Merrill
2019-10-30 23:29 ` [C++ PATCH] Fix " Jakub Jelinek
0 siblings, 1 reply; 4+ messages in thread
From: Jason Merrill @ 2019-10-29 20:26 UTC (permalink / raw)
To: Jakub Jelinek, Martin Sebor; +Cc: gcc-patches
On 10/22/19 11:03 AM, Jakub Jelinek wrote:
> Hi!
>
> The following patch is just a partial fix for a regression introduced
> in the PR90947 changes, the testcase is fixed for just C++17/20.
> type_initializer_zero_p has been added to the generic code, supposedly
> because similar initializer_zerop is in generic code too, but that
> means it has a hand-written copy of next_initializable_field which can't
> do exactly what next_initializable_field does.
>
> The following patch moves it into the C++ FE which is the only user of that
> function and uses next_initializable_field in there.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> I'm afraid I'm lost on how to fix the C++11/14 case, the object
> being initialized has std::atomic<int> type, which doesn't have any
> direct non-static data members, and has std::__atomic_base<int> as base
> class that has some field. The only FIELD_DECL in std::atomic<int>
> is DECL_ARTIFICIAL field for the base class, so next_initializable_field
> or the hand-written variant thereof doesn't find any initializable fields
> for 11/14. The initializer is initializer list { {1} } and the function
> just returns true if it doesn't find any initializable fields, so in the end
> we misoptimize it as { {0} }.
I think type_initializer_zero_p should return false if
CLASSTYPE_NON_AGGREGATE; we can't expect that value-initialization will
have the intended effect in that case.
> 2019-10-22 Jakub Jelinek <jakub@redhat.com>
>
> PR c++/90947
> * tree.h (type_initializer_zero_p): Remove.
> * tree.c (type_initializer_zero_p): Remove.
> cp/
> * cp-tree.h (type_initializer_zero_p): Declare.
> * decl.c (reshape_init_array_1): Formatting fix.
> * tree.c (type_initializer_zero_p): New function. Moved from
> ../tree.c, use next_initializable_field, formatting fix.
>
> --- gcc/tree.h.jj 2019-09-20 12:25:13.737920929 +0200
> +++ gcc/tree.h 2019-10-22 10:07:26.411826804 +0200
> @@ -4690,12 +4690,6 @@ extern tree first_field (const_tree);
> extern bool initializer_zerop (const_tree, bool * = NULL);
> extern bool initializer_each_zero_or_onep (const_tree);
>
> -/* Analogous to initializer_zerop but also examines the type for
> - which the initializer is being used. Unlike initializer_zerop,
> - considers empty strings to be zero initializers for arrays and
> - non-zero for pointers. */
> -extern bool type_initializer_zero_p (tree, tree);
> -
> extern wide_int vector_cst_int_elt (const_tree, unsigned int);
> extern tree vector_cst_elt (const_tree, unsigned int);
>
> --- gcc/tree.c.jj 2019-10-19 09:22:14.830893404 +0200
> +++ gcc/tree.c 2019-10-22 10:08:36.501748481 +0200
> @@ -11396,73 +11396,6 @@ initializer_each_zero_or_onep (const_tre
> }
> }
>
> -/* Given an initializer INIT for a TYPE, return true if INIT is zero
> - so that it can be replaced by value initialization. This function
> - distinguishes betwen empty strings as initializers for arrays and
> - for pointers (which make it return false). */
> -
> -bool
> -type_initializer_zero_p (tree type, tree init)
> -{
> - if (type == error_mark_node || init == error_mark_node)
> - return false;
> -
> - STRIP_NOPS (init);
> -
> - if (POINTER_TYPE_P (type))
> - return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
> -
> - if (TREE_CODE (init) != CONSTRUCTOR)
> - return initializer_zerop (init);
> -
> - if (TREE_CODE (type) == ARRAY_TYPE)
> - {
> - tree elt_type = TREE_TYPE (type);
> - elt_type = TYPE_MAIN_VARIANT (elt_type);
> - if (elt_type == char_type_node)
> - return initializer_zerop (init);
> -
> - tree elt_init;
> - unsigned HOST_WIDE_INT i;
> - FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
> - if (!type_initializer_zero_p (elt_type, elt_init))
> - return false;
> - return true;
> - }
> -
> - if (TREE_CODE (type) != RECORD_TYPE)
> - return initializer_zerop (init);
> -
> - tree fld = TYPE_FIELDS (type);
> -
> - tree fld_init;
> - unsigned HOST_WIDE_INT i;
> - FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
> - {
> - /* Advance to the next member, skipping over everything that
> - canot be initialized (including unnamed bit-fields). */
> - while (TREE_CODE (fld) != FIELD_DECL
> - || DECL_ARTIFICIAL (fld)
> - || (DECL_BIT_FIELD (fld) && !DECL_NAME (fld)))
> - {
> - fld = DECL_CHAIN (fld);
> - if (!fld)
> - return true;
> - continue;
> - }
> -
> - tree fldtype = TREE_TYPE (fld);
> - if (!type_initializer_zero_p (fldtype, fld_init))
> - return false;
> -
> - fld = DECL_CHAIN (fld);
> - if (!fld)
> - break;
> - }
> -
> - return true;
> -}
> -
> /* Check if vector VEC consists of all the equal elements and
> that the number of elements corresponds to the type of VEC.
> The function returns first element of the vector
> --- gcc/cp/cp-tree.h.jj 2019-10-22 08:15:53.810775827 +0200
> +++ gcc/cp/cp-tree.h 2019-10-22 10:10:57.265582861 +0200
> @@ -7379,6 +7379,11 @@ extern tree cxx_copy_lang_qualifiers (c
>
> extern void cxx_print_statistics (void);
> extern bool maybe_warn_zero_as_null_pointer_constant (tree, location_t);
> +/* Analogous to initializer_zerop but also examines the type for
> + which the initializer is being used. Unlike initializer_zerop,
> + considers empty strings to be zero initializers for arrays and
> + non-zero for pointers. */
> +extern bool type_initializer_zero_p (tree, tree);
>
> /* in ptree.c */
> extern void cxx_print_xnode (FILE *, tree, int);
> --- gcc/cp/decl.c.jj 2019-10-22 08:57:12.913654620 +0200
> +++ gcc/cp/decl.c 2019-10-22 10:13:39.038094034 +0200
> @@ -5982,9 +5982,8 @@ reshape_init_array_1 (tree elt_type, tre
> /* Pointers initialized to strings must be treated as non-zero
> even if the string is empty. */
> tree init_type = TREE_TYPE (elt_init);
> - if ((POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)))
> - last_nonzero = index;
> - else if (!type_initializer_zero_p (elt_type, elt_init))
> + if (POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)
> + || !type_initializer_zero_p (elt_type, elt_init))
> last_nonzero = index;
>
> /* This can happen with an invalid initializer (c++/54501). */
> --- gcc/cp/tree.c.jj 2019-10-19 09:22:16.594866462 +0200
> +++ gcc/cp/tree.c 2019-10-22 10:10:29.151015397 +0200
> @@ -5527,6 +5527,65 @@ maybe_warn_zero_as_null_pointer_constant
> return false;
> }
> \f
> +/* Given an initializer INIT for a TYPE, return true if INIT is zero
> + so that it can be replaced by value initialization. This function
> + distinguishes betwen empty strings as initializers for arrays and
> + for pointers (which make it return false). */
> +
> +bool
> +type_initializer_zero_p (tree type, tree init)
> +{
> + if (type == error_mark_node || init == error_mark_node)
> + return false;
> +
> + STRIP_NOPS (init);
> +
> + if (POINTER_TYPE_P (type))
> + return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
> +
> + if (TREE_CODE (init) != CONSTRUCTOR)
> + return initializer_zerop (init);
> +
> + if (TREE_CODE (type) == ARRAY_TYPE)
> + {
> + tree elt_type = TREE_TYPE (type);
> + elt_type = TYPE_MAIN_VARIANT (elt_type);
> + if (elt_type == char_type_node)
> + return initializer_zerop (init);
> +
> + tree elt_init;
> + unsigned HOST_WIDE_INT i;
> + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
> + if (!type_initializer_zero_p (elt_type, elt_init))
> + return false;
> + return true;
> + }
> +
> + if (TREE_CODE (type) != RECORD_TYPE)
> + return initializer_zerop (init);
> +
> + tree fld = TYPE_FIELDS (type);
> +
> + tree fld_init;
> + unsigned HOST_WIDE_INT i;
> + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
> + {
> + fld = next_initializable_field (fld);
> + if (!fld)
> + return true;
> +
> + tree fldtype = TREE_TYPE (fld);
> + if (!type_initializer_zero_p (fldtype, fld_init))
> + return false;
> +
> + fld = DECL_CHAIN (fld);
> + if (!fld)
> + break;
> + }
> +
> + return true;
> +}
> +\f
> #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
> /* Complain that some language-specific thing hanging off a tree
> node has been accessed improperly. */
>
> Jakub
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [C++ PATCH] Fix a recent regression (PR c++/90947)
2019-10-29 20:26 ` Jason Merrill
@ 2019-10-30 23:29 ` Jakub Jelinek
2019-10-31 7:27 ` Jason Merrill
0 siblings, 1 reply; 4+ messages in thread
From: Jakub Jelinek @ 2019-10-30 23:29 UTC (permalink / raw)
To: Jason Merrill; +Cc: Martin Sebor, gcc-patches
On Tue, Oct 29, 2019 at 04:26:14PM -0400, Jason Merrill wrote:
> I think type_initializer_zero_p should return false if
> CLASSTYPE_NON_AGGREGATE; we can't expect that value-initialization will have
> the intended effect in that case.
That indeed works for this testcase and doesn't break anything else in the
testsuite. I've actually used TYPE_NON_AGGREGATE_CLASS because a
RECORD_TYPE might not be always a CLASS_TYPE_P.
Here is what I've bootstrapped/regtested on x86_64-linux and i686-linux, ok
for trunk?
2019-10-30 Jakub Jelinek <jakub@redhat.com>
PR c++/90947
* tree.h (type_initializer_zero_p): Remove.
* tree.c (type_initializer_zero_p): Remove.
cp/
* cp-tree.h (type_initializer_zero_p): Declare.
* decl.c (reshape_init_array_1): Formatting fix.
* tree.c (type_initializer_zero_p): New function. Moved from
../tree.c, use next_initializable_field, formatting fix. Return
false for TYPE_NON_AGGREGATE_CLASS types.
--- gcc/tree.h.jj 2019-10-30 08:13:49.017848260 +0100
+++ gcc/tree.h 2019-10-30 08:57:59.457046198 +0100
@@ -4690,12 +4690,6 @@ extern tree first_field (const_tree);
extern bool initializer_zerop (const_tree, bool * = NULL);
extern bool initializer_each_zero_or_onep (const_tree);
-/* Analogous to initializer_zerop but also examines the type for
- which the initializer is being used. Unlike initializer_zerop,
- considers empty strings to be zero initializers for arrays and
- non-zero for pointers. */
-extern bool type_initializer_zero_p (tree, tree);
-
extern wide_int vector_cst_int_elt (const_tree, unsigned int);
extern tree vector_cst_elt (const_tree, unsigned int);
--- gcc/tree.c.jj 2019-10-30 08:13:48.974848922 +0100
+++ gcc/tree.c 2019-10-30 08:57:59.460046152 +0100
@@ -11396,73 +11396,6 @@ initializer_each_zero_or_onep (const_tre
}
}
-/* Given an initializer INIT for a TYPE, return true if INIT is zero
- so that it can be replaced by value initialization. This function
- distinguishes betwen empty strings as initializers for arrays and
- for pointers (which make it return false). */
-
-bool
-type_initializer_zero_p (tree type, tree init)
-{
- if (type == error_mark_node || init == error_mark_node)
- return false;
-
- STRIP_NOPS (init);
-
- if (POINTER_TYPE_P (type))
- return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
-
- if (TREE_CODE (init) != CONSTRUCTOR)
- return initializer_zerop (init);
-
- if (TREE_CODE (type) == ARRAY_TYPE)
- {
- tree elt_type = TREE_TYPE (type);
- elt_type = TYPE_MAIN_VARIANT (elt_type);
- if (elt_type == char_type_node)
- return initializer_zerop (init);
-
- tree elt_init;
- unsigned HOST_WIDE_INT i;
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
- if (!type_initializer_zero_p (elt_type, elt_init))
- return false;
- return true;
- }
-
- if (TREE_CODE (type) != RECORD_TYPE)
- return initializer_zerop (init);
-
- tree fld = TYPE_FIELDS (type);
-
- tree fld_init;
- unsigned HOST_WIDE_INT i;
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
- {
- /* Advance to the next member, skipping over everything that
- canot be initialized (including unnamed bit-fields). */
- while (TREE_CODE (fld) != FIELD_DECL
- || DECL_ARTIFICIAL (fld)
- || (DECL_BIT_FIELD (fld) && !DECL_NAME (fld)))
- {
- fld = DECL_CHAIN (fld);
- if (!fld)
- return true;
- continue;
- }
-
- tree fldtype = TREE_TYPE (fld);
- if (!type_initializer_zero_p (fldtype, fld_init))
- return false;
-
- fld = DECL_CHAIN (fld);
- if (!fld)
- break;
- }
-
- return true;
-}
-
/* Check if vector VEC consists of all the equal elements and
that the number of elements corresponds to the type of VEC.
The function returns first element of the vector
--- gcc/cp/cp-tree.h.jj 2019-10-30 08:13:48.819851308 +0100
+++ gcc/cp/cp-tree.h 2019-10-30 08:57:59.462046121 +0100
@@ -7380,6 +7380,11 @@ extern tree cxx_copy_lang_qualifiers (c
extern void cxx_print_statistics (void);
extern bool maybe_warn_zero_as_null_pointer_constant (tree, location_t);
+/* Analogous to initializer_zerop but also examines the type for
+ which the initializer is being used. Unlike initializer_zerop,
+ considers empty strings to be zero initializers for arrays and
+ non-zero for pointers. */
+extern bool type_initializer_zero_p (tree, tree);
/* in ptree.c */
extern void cxx_print_xnode (FILE *, tree, int);
--- gcc/cp/decl.c.jj 2019-10-30 08:13:48.885850291 +0100
+++ gcc/cp/decl.c 2019-10-30 08:57:59.466046060 +0100
@@ -5972,9 +5972,8 @@ reshape_init_array_1 (tree elt_type, tre
/* Pointers initialized to strings must be treated as non-zero
even if the string is empty. */
tree init_type = TREE_TYPE (elt_init);
- if ((POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)))
- last_nonzero = index;
- else if (!type_initializer_zero_p (elt_type, elt_init))
+ if (POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)
+ || !type_initializer_zero_p (elt_type, elt_init))
last_nonzero = index;
/* This can happen with an invalid initializer (c++/54501). */
--- gcc/cp/tree.c.jj 2019-10-30 08:13:48.777851956 +0100
+++ gcc/cp/tree.c 2019-10-30 09:17:23.743135729 +0100
@@ -5541,6 +5541,68 @@ maybe_warn_zero_as_null_pointer_constant
return false;
}
\f
+/* Given an initializer INIT for a TYPE, return true if INIT is zero
+ so that it can be replaced by value initialization. This function
+ distinguishes betwen empty strings as initializers for arrays and
+ for pointers (which make it return false). */
+
+bool
+type_initializer_zero_p (tree type, tree init)
+{
+ if (type == error_mark_node || init == error_mark_node)
+ return false;
+
+ STRIP_NOPS (init);
+
+ if (POINTER_TYPE_P (type))
+ return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
+
+ if (TREE_CODE (init) != CONSTRUCTOR)
+ return initializer_zerop (init);
+
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ tree elt_type = TREE_TYPE (type);
+ elt_type = TYPE_MAIN_VARIANT (elt_type);
+ if (elt_type == char_type_node)
+ return initializer_zerop (init);
+
+ tree elt_init;
+ unsigned HOST_WIDE_INT i;
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
+ if (!type_initializer_zero_p (elt_type, elt_init))
+ return false;
+ return true;
+ }
+
+ if (TREE_CODE (type) != RECORD_TYPE)
+ return initializer_zerop (init);
+
+ if (TYPE_NON_AGGREGATE_CLASS (type))
+ return false;
+
+ tree fld = TYPE_FIELDS (type);
+
+ tree fld_init;
+ unsigned HOST_WIDE_INT i;
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
+ {
+ fld = next_initializable_field (fld);
+ if (!fld)
+ return true;
+
+ tree fldtype = TREE_TYPE (fld);
+ if (!type_initializer_zero_p (fldtype, fld_init))
+ return false;
+
+ fld = DECL_CHAIN (fld);
+ if (!fld)
+ break;
+ }
+
+ return true;
+}
+\f
#if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
/* Complain that some language-specific thing hanging off a tree
node has been accessed improperly. */
--- gcc/testsuite/g++.dg/init/array54.C.jj 2019-10-30 09:21:12.676608668 +0100
+++ gcc/testsuite/g++.dg/init/array54.C 2019-10-30 09:26:42.813522422 +0100
@@ -0,0 +1,13 @@
+// PR c++/90947
+// { dg-do run { target c++11 } }
+
+#include <atomic>
+
+static std::atomic<int> a[1] { {1} };
+
+int
+main ()
+{
+ if (a[0].load () != 1)
+ __builtin_abort ();
+}
Jakub
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [C++ PATCH] Fix a recent regression (PR c++/90947)
2019-10-30 23:29 ` [C++ PATCH] Fix " Jakub Jelinek
@ 2019-10-31 7:27 ` Jason Merrill
0 siblings, 0 replies; 4+ messages in thread
From: Jason Merrill @ 2019-10-31 7:27 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Martin Sebor, gcc-patches
On 10/30/19 7:29 PM, Jakub Jelinek wrote:
> On Tue, Oct 29, 2019 at 04:26:14PM -0400, Jason Merrill wrote:
>> I think type_initializer_zero_p should return false if
>> CLASSTYPE_NON_AGGREGATE; we can't expect that value-initialization will have
>> the intended effect in that case.
>
> That indeed works for this testcase and doesn't break anything else in the
> testsuite. I've actually used TYPE_NON_AGGREGATE_CLASS because a
> RECORD_TYPE might not be always a CLASS_TYPE_P.
>
> Here is what I've bootstrapped/regtested on x86_64-linux and i686-linux, ok
> for trunk?
OK.
> 2019-10-30 Jakub Jelinek <jakub@redhat.com>
>
> PR c++/90947
> * tree.h (type_initializer_zero_p): Remove.
> * tree.c (type_initializer_zero_p): Remove.
> cp/
> * cp-tree.h (type_initializer_zero_p): Declare.
> * decl.c (reshape_init_array_1): Formatting fix.
> * tree.c (type_initializer_zero_p): New function. Moved from
> ../tree.c, use next_initializable_field, formatting fix. Return
> false for TYPE_NON_AGGREGATE_CLASS types.
>
> --- gcc/tree.h.jj 2019-10-30 08:13:49.017848260 +0100
> +++ gcc/tree.h 2019-10-30 08:57:59.457046198 +0100
> @@ -4690,12 +4690,6 @@ extern tree first_field (const_tree);
> extern bool initializer_zerop (const_tree, bool * = NULL);
> extern bool initializer_each_zero_or_onep (const_tree);
>
> -/* Analogous to initializer_zerop but also examines the type for
> - which the initializer is being used. Unlike initializer_zerop,
> - considers empty strings to be zero initializers for arrays and
> - non-zero for pointers. */
> -extern bool type_initializer_zero_p (tree, tree);
> -
> extern wide_int vector_cst_int_elt (const_tree, unsigned int);
> extern tree vector_cst_elt (const_tree, unsigned int);
>
> --- gcc/tree.c.jj 2019-10-30 08:13:48.974848922 +0100
> +++ gcc/tree.c 2019-10-30 08:57:59.460046152 +0100
> @@ -11396,73 +11396,6 @@ initializer_each_zero_or_onep (const_tre
> }
> }
>
> -/* Given an initializer INIT for a TYPE, return true if INIT is zero
> - so that it can be replaced by value initialization. This function
> - distinguishes betwen empty strings as initializers for arrays and
> - for pointers (which make it return false). */
> -
> -bool
> -type_initializer_zero_p (tree type, tree init)
> -{
> - if (type == error_mark_node || init == error_mark_node)
> - return false;
> -
> - STRIP_NOPS (init);
> -
> - if (POINTER_TYPE_P (type))
> - return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
> -
> - if (TREE_CODE (init) != CONSTRUCTOR)
> - return initializer_zerop (init);
> -
> - if (TREE_CODE (type) == ARRAY_TYPE)
> - {
> - tree elt_type = TREE_TYPE (type);
> - elt_type = TYPE_MAIN_VARIANT (elt_type);
> - if (elt_type == char_type_node)
> - return initializer_zerop (init);
> -
> - tree elt_init;
> - unsigned HOST_WIDE_INT i;
> - FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
> - if (!type_initializer_zero_p (elt_type, elt_init))
> - return false;
> - return true;
> - }
> -
> - if (TREE_CODE (type) != RECORD_TYPE)
> - return initializer_zerop (init);
> -
> - tree fld = TYPE_FIELDS (type);
> -
> - tree fld_init;
> - unsigned HOST_WIDE_INT i;
> - FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
> - {
> - /* Advance to the next member, skipping over everything that
> - canot be initialized (including unnamed bit-fields). */
> - while (TREE_CODE (fld) != FIELD_DECL
> - || DECL_ARTIFICIAL (fld)
> - || (DECL_BIT_FIELD (fld) && !DECL_NAME (fld)))
> - {
> - fld = DECL_CHAIN (fld);
> - if (!fld)
> - return true;
> - continue;
> - }
> -
> - tree fldtype = TREE_TYPE (fld);
> - if (!type_initializer_zero_p (fldtype, fld_init))
> - return false;
> -
> - fld = DECL_CHAIN (fld);
> - if (!fld)
> - break;
> - }
> -
> - return true;
> -}
> -
> /* Check if vector VEC consists of all the equal elements and
> that the number of elements corresponds to the type of VEC.
> The function returns first element of the vector
> --- gcc/cp/cp-tree.h.jj 2019-10-30 08:13:48.819851308 +0100
> +++ gcc/cp/cp-tree.h 2019-10-30 08:57:59.462046121 +0100
> @@ -7380,6 +7380,11 @@ extern tree cxx_copy_lang_qualifiers (c
>
> extern void cxx_print_statistics (void);
> extern bool maybe_warn_zero_as_null_pointer_constant (tree, location_t);
> +/* Analogous to initializer_zerop but also examines the type for
> + which the initializer is being used. Unlike initializer_zerop,
> + considers empty strings to be zero initializers for arrays and
> + non-zero for pointers. */
> +extern bool type_initializer_zero_p (tree, tree);
>
> /* in ptree.c */
> extern void cxx_print_xnode (FILE *, tree, int);
> --- gcc/cp/decl.c.jj 2019-10-30 08:13:48.885850291 +0100
> +++ gcc/cp/decl.c 2019-10-30 08:57:59.466046060 +0100
> @@ -5972,9 +5972,8 @@ reshape_init_array_1 (tree elt_type, tre
> /* Pointers initialized to strings must be treated as non-zero
> even if the string is empty. */
> tree init_type = TREE_TYPE (elt_init);
> - if ((POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)))
> - last_nonzero = index;
> - else if (!type_initializer_zero_p (elt_type, elt_init))
> + if (POINTER_TYPE_P (elt_type) != POINTER_TYPE_P (init_type)
> + || !type_initializer_zero_p (elt_type, elt_init))
> last_nonzero = index;
>
> /* This can happen with an invalid initializer (c++/54501). */
> --- gcc/cp/tree.c.jj 2019-10-30 08:13:48.777851956 +0100
> +++ gcc/cp/tree.c 2019-10-30 09:17:23.743135729 +0100
> @@ -5541,6 +5541,68 @@ maybe_warn_zero_as_null_pointer_constant
> return false;
> }
> \f
> +/* Given an initializer INIT for a TYPE, return true if INIT is zero
> + so that it can be replaced by value initialization. This function
> + distinguishes betwen empty strings as initializers for arrays and
> + for pointers (which make it return false). */
> +
> +bool
> +type_initializer_zero_p (tree type, tree init)
> +{
> + if (type == error_mark_node || init == error_mark_node)
> + return false;
> +
> + STRIP_NOPS (init);
> +
> + if (POINTER_TYPE_P (type))
> + return TREE_CODE (init) != STRING_CST && initializer_zerop (init);
> +
> + if (TREE_CODE (init) != CONSTRUCTOR)
> + return initializer_zerop (init);
> +
> + if (TREE_CODE (type) == ARRAY_TYPE)
> + {
> + tree elt_type = TREE_TYPE (type);
> + elt_type = TYPE_MAIN_VARIANT (elt_type);
> + if (elt_type == char_type_node)
> + return initializer_zerop (init);
> +
> + tree elt_init;
> + unsigned HOST_WIDE_INT i;
> + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init)
> + if (!type_initializer_zero_p (elt_type, elt_init))
> + return false;
> + return true;
> + }
> +
> + if (TREE_CODE (type) != RECORD_TYPE)
> + return initializer_zerop (init);
> +
> + if (TYPE_NON_AGGREGATE_CLASS (type))
> + return false;
> +
> + tree fld = TYPE_FIELDS (type);
> +
> + tree fld_init;
> + unsigned HOST_WIDE_INT i;
> + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init)
> + {
> + fld = next_initializable_field (fld);
> + if (!fld)
> + return true;
> +
> + tree fldtype = TREE_TYPE (fld);
> + if (!type_initializer_zero_p (fldtype, fld_init))
> + return false;
> +
> + fld = DECL_CHAIN (fld);
> + if (!fld)
> + break;
> + }
> +
> + return true;
> +}
> +\f
> #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
> /* Complain that some language-specific thing hanging off a tree
> node has been accessed improperly. */
> --- gcc/testsuite/g++.dg/init/array54.C.jj 2019-10-30 09:21:12.676608668 +0100
> +++ gcc/testsuite/g++.dg/init/array54.C 2019-10-30 09:26:42.813522422 +0100
> @@ -0,0 +1,13 @@
> +// PR c++/90947
> +// { dg-do run { target c++11 } }
> +
> +#include <atomic>
> +
> +static std::atomic<int> a[1] { {1} };
> +
> +int
> +main ()
> +{
> + if (a[0].load () != 1)
> + __builtin_abort ();
> +}
>
>
> Jakub
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-10-31 2:35 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-22 15:20 [C++ PATCH] Partial fix for a recent regression (PR c++/90947) Jakub Jelinek
2019-10-29 20:26 ` Jason Merrill
2019-10-30 23:29 ` [C++ PATCH] Fix " Jakub Jelinek
2019-10-31 7:27 ` Jason Merrill
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