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| author | Aaron Ballman <aaron@aaronballman.com> | 2025-11-10 07:40:31 -0500 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2025-11-10 07:40:31 -0500 |
| commit | 309729e8279a675dcef2da8912c7679ebca5c641 (patch) | |
| tree | 4fddc5aabcfcf2c44fea60e4a3c39c8dfd002e46 /clang | |
| parent | 2705951a228222f3f642279a80dd095531f7d524 (diff) | |
| download | llvm-309729e8279a675dcef2da8912c7679ebca5c641.zip llvm-309729e8279a675dcef2da8912c7679ebca5c641.tar.gz llvm-309729e8279a675dcef2da8912c7679ebca5c641.tar.bz2 | |
[C2y] Claim nonconformance to WG14 N3348 (#166966)
This paper allows use of * in a multidimensional array extent within a
_Generic selection association, as a wildcard for any array extent.
Clang does not currently support this feature, so this is just some
initial test coverage along with an update to the conformance site.
Diffstat (limited to 'clang')
| -rw-r--r-- | clang/test/C/C2y/n3348.c | 44 | ||||
| -rw-r--r-- | clang/www/c_status.html | 2 |
2 files changed, 45 insertions, 1 deletions
diff --git a/clang/test/C/C2y/n3348.c b/clang/test/C/C2y/n3348.c new file mode 100644 index 0000000..e20c9f7 --- /dev/null +++ b/clang/test/C/C2y/n3348.c @@ -0,0 +1,44 @@ +// RUN: %clang_cc1 -verify -std=c2y -Wall -pedantic %s + +/* WG14 N3348: No + * Matching of Multi-Dimensional Arrays in Generic Selection Expressions + * + * This allows use of * in a _Generic association as a placeholder for any size + * value. + * + * FIXME: Clang doesn't yet implement this paper. When we do implement it, we + * should expose the functionality in earlier language modes (C89) for + * compatibility with GCC. + */ + +void test(int n, int m) { + static_assert(1 == _Generic(int[3][2], int[3][*]: 1, int[2][*]: 0)); /* expected-error {{star modifier used outside of function prototype}} + expected-error {{array has incomplete element type 'int[]'}} + */ + static_assert(1 == _Generic(int[3][2], int[*][2]: 1, int[*][3]: 0)); // expected-error {{star modifier used outside of function prototype}} + static_assert(1 == _Generic(int[3][n], int[3][*]: 1, int[2][*]: 0)); /* expected-error {{star modifier used outside of function prototype}} + expected-error {{array has incomplete element type 'int[]'}} + */ + static_assert(1 == _Generic(int[n][m], int[*][*]: 1, char[*][*]: 0)); /* expected-error 2 {{star modifier used outside of function prototype}} + expected-error {{array has incomplete element type 'int[]'}} + */ + static_assert(1 == _Generic(int(*)[2], int(*)[*]: 1)); // expected-error {{star modifier used outside of function prototype}} +} + +void questionable() { + // GCC accepts this despite the * appearing outside of a generic association, + // but it's not clear whether that's intentionally supported or an oversight. + // It gives a warning about * being used outside of a declaration, but not + // with an associated warning group. + static_assert(1 == _Generic(int[*][*], int[2][100]: 1)); /* expected-error 2 {{star modifier used outside of function prototype}} + expected-error {{array has incomplete element type 'int[]'}} + */ + // GCC claims this matches multiple associations, so the functionality seems + // like it may be intended to work? + (void)_Generic(int[*][*], /* expected-error 2 {{star modifier used outside of function prototype}} + expected-error {{array has incomplete element type 'int[]'}} + */ + int[2][100]: 1, + int[3][1000]: 2, + ); +} diff --git a/clang/www/c_status.html b/clang/www/c_status.html index 2c1f6f4..ccf19ea 100644 --- a/clang/www/c_status.html +++ b/clang/www/c_status.html @@ -324,7 +324,7 @@ conformance.</p> <tr> <td>Matching of Multi-Dimensional Arrays in Generic Selection Expressions</td> <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3348.pdf">N3348</a></td> - <td class="unknown" align="center">Unknown</td> + <td class="none" align="center">No</td> </tr> <tr> <td>The __COUNTER__ predefined macro</td> |