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author | Joseph Myers <joseph@codesourcery.com> | 2023-05-15 23:17:48 +0000 |
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committer | Joseph Myers <joseph@codesourcery.com> | 2023-05-15 23:17:48 +0000 |
commit | d62d5686f41bb4ea50b8de640fac51decd24199a (patch) | |
tree | 497c7c56004b5d89d717108bd9ef60777615ca54 | |
parent | 2f27218ced2a23819c8fe8ba30ae74911b2c3cf1 (diff) | |
download | gcc-d62d5686f41bb4ea50b8de640fac51decd24199a.zip gcc-d62d5686f41bb4ea50b8de640fac51decd24199a.tar.gz gcc-d62d5686f41bb4ea50b8de640fac51decd24199a.tar.bz2 |
c: Ignore _Atomic on function return type for C2x
For C2x it was decided that _Atomic would be completely ignored on
function return types (just as was done for qualifiers in C11 DR#423),
to eliminate the potential for an rvalue returned by a function having
_Atomic-qualified type when an rvalue resulting from lvalue-to-rvalue
conversion could not have such a type. Implement this for GCC.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
* c-decl.cc (grokdeclarator): Ignore _Atomic on function return
type for C2x.
gcc/testsuite/
* gcc.dg/qual-return-9.c, gcc.dg/qual-return-10.c: New tests.
-rw-r--r-- | gcc/c/c-decl.cc | 7 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/qual-return-10.c | 12 | ||||
-rw-r--r-- | gcc/testsuite/gcc.dg/qual-return-9.c | 32 |
3 files changed, 49 insertions, 2 deletions
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc index 1b53f2d..90d7cd2 100644 --- a/gcc/c/c-decl.cc +++ b/gcc/c/c-decl.cc @@ -7412,9 +7412,12 @@ grokdeclarator (const struct c_declarator *declarator, them for noreturn functions. The resolution of C11 DR#423 means qualifiers (other than _Atomic) are actually removed from the return type when - determining the function type. */ + determining the function type. For C2X, _Atomic is + removed as well. */ int quals_used = type_quals; - if (flag_isoc11) + if (flag_isoc2x) + quals_used = 0; + else if (flag_isoc11) quals_used &= TYPE_QUAL_ATOMIC; if (quals_used && VOID_TYPE_P (type) && really_funcdef) pedwarn (specs_loc, 0, diff --git a/gcc/testsuite/gcc.dg/qual-return-10.c b/gcc/testsuite/gcc.dg/qual-return-10.c new file mode 100644 index 0000000..c7dd6ad --- /dev/null +++ b/gcc/testsuite/gcc.dg/qual-return-10.c @@ -0,0 +1,12 @@ +/* Test qualifiers on function return types in C2X (C2X version of + qual-return-6.c): those qualifiers are now ignored for all purposes, + including _Atomic, but should still get warnings. */ +/* { dg-do compile } */ +/* { dg-options "-std=c2x -Wignored-qualifiers" } */ + +const int f1 (void); /* { dg-warning "qualifiers ignored" } */ +volatile int f2 (void) { return 0; } /* { dg-warning "qualifiers ignored" } */ +const volatile void f3 (void) { } /* { dg-warning "qualifiers ignored" } */ +const void f4 (void); /* { dg-warning "qualifiers ignored" } */ +_Atomic int f5 (void); /* { dg-warning "qualifiers ignored" } */ +_Atomic int f6 (void) { return 0; } /* { dg-warning "qualifiers ignored" } */ diff --git a/gcc/testsuite/gcc.dg/qual-return-9.c b/gcc/testsuite/gcc.dg/qual-return-9.c new file mode 100644 index 0000000..7762782 --- /dev/null +++ b/gcc/testsuite/gcc.dg/qual-return-9.c @@ -0,0 +1,32 @@ +/* Test qualifiers on function return types in C2X (C2X version of + qual-return-5.c): those qualifiers are now ignored for all purposes, + including _Atomic. */ +/* { dg-do compile } */ +/* { dg-options "-std=c2x -pedantic-errors" } */ + +int f1 (void); +const int f1 (void); +volatile int f1 (void) { return 0; } + +int *restrict f2 (void) { return 0; } +int *f2 (void); + +const volatile long f3 (void); +long f3 (void); + +const volatile void f4 (void) { } +void f4 (void); + +_Atomic int f5 (void); +int f5 (void); + +int f6 (void); +_Atomic int f6 (void) { return 0; } + +/* The standard seems unclear regarding the case where restrict is + applied to a function return type that may not be + restrict-qualified; assume here that it is disallowed. */ +restrict int f7 (void); /* { dg-error "restrict" } */ + +typedef void FT (void); +FT *restrict f8 (void); /* { dg-error "restrict" } */ |