* [PATCH] c++: Allow IS_FAKE_BASE_TYPE for union types [PR114954]
@ 2024-05-06 6:32 Nathaniel Shead
2024-05-06 16:39 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Nathaniel Shead @ 2024-05-06 6:32 UTC (permalink / raw)
To: gcc-patches; +Cc: Jason Merrill
Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
-- >8 --
In some circumstances, unions can also have an __as_base type; we need
to make sure that IS_FAKE_BASE_TYPE correctly recognises this.
PR c++/114954
gcc/cp/ChangeLog:
* cp-tree.h (IS_FAKE_BASE_TYPE): Also apply to unions.
gcc/testsuite/ChangeLog:
* g++.dg/modules/pr114954.C: New test.
Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
---
gcc/cp/cp-tree.h | 2 +-
gcc/testsuite/g++.dg/modules/pr114954.C | 14 ++++++++++++++
2 files changed, 15 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/modules/pr114954.C
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 933504b4821..fa24217eb2b 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -2616,7 +2616,7 @@ struct GTY(()) lang_type {
/* True iff NODE is the CLASSTYPE_AS_BASE version of some type. */
#define IS_FAKE_BASE_TYPE(NODE) \
- (TREE_CODE (NODE) == RECORD_TYPE \
+ (RECORD_OR_UNION_TYPE_P (NODE) \
&& TYPE_CONTEXT (NODE) && CLASS_TYPE_P (TYPE_CONTEXT (NODE)) \
&& CLASSTYPE_AS_BASE (TYPE_CONTEXT (NODE)) == (NODE))
diff --git a/gcc/testsuite/g++.dg/modules/pr114954.C b/gcc/testsuite/g++.dg/modules/pr114954.C
new file mode 100644
index 00000000000..a9787140808
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr114954.C
@@ -0,0 +1,14 @@
+// PR c++/114954
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi main }
+
+export module main;
+
+template <int N>
+union U {
+private:
+ char a[N + 1];
+ int b;
+};
+
+U<4> p;
--
2.43.2
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] c++: Allow IS_FAKE_BASE_TYPE for union types [PR114954]
2024-05-06 6:32 [PATCH] c++: Allow IS_FAKE_BASE_TYPE for union types [PR114954] Nathaniel Shead
@ 2024-05-06 16:39 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2024-05-06 16:39 UTC (permalink / raw)
To: Nathaniel Shead, gcc-patches
On 5/6/24 02:32, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
>
> -- >8 --
>
> In some circumstances, unions can also have an __as_base type;
Hmm, even though unions can't be bases I guess that is needed for
something like
union U {
int i;
private:
char c[5];
};
struct A {
[[no_unique_address]] U u;
char d;
};
static_assert (sizeof (A) == sizeof (U));
The patch is OK.
> we need to make sure that IS_FAKE_BASE_TYPE correctly recognises this.
>
> PR c++/114954
>
> gcc/cp/ChangeLog:
>
> * cp-tree.h (IS_FAKE_BASE_TYPE): Also apply to unions.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/modules/pr114954.C: New test.
>
> Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> ---
> gcc/cp/cp-tree.h | 2 +-
> gcc/testsuite/g++.dg/modules/pr114954.C | 14 ++++++++++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/modules/pr114954.C
>
> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> index 933504b4821..fa24217eb2b 100644
> --- a/gcc/cp/cp-tree.h
> +++ b/gcc/cp/cp-tree.h
> @@ -2616,7 +2616,7 @@ struct GTY(()) lang_type {
>
> /* True iff NODE is the CLASSTYPE_AS_BASE version of some type. */
> #define IS_FAKE_BASE_TYPE(NODE) \
> - (TREE_CODE (NODE) == RECORD_TYPE \
> + (RECORD_OR_UNION_TYPE_P (NODE) \
> && TYPE_CONTEXT (NODE) && CLASS_TYPE_P (TYPE_CONTEXT (NODE)) \
> && CLASSTYPE_AS_BASE (TYPE_CONTEXT (NODE)) == (NODE))
>
> diff --git a/gcc/testsuite/g++.dg/modules/pr114954.C b/gcc/testsuite/g++.dg/modules/pr114954.C
> new file mode 100644
> index 00000000000..a9787140808
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/pr114954.C
> @@ -0,0 +1,14 @@
> +// PR c++/114954
> +// { dg-additional-options "-fmodules-ts" }
> +// { dg-module-cmi main }
> +
> +export module main;
> +
> +template <int N>
> +union U {
> +private:
> + char a[N + 1];
> + int b;
> +};
> +
> +U<4> p;
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