On 5/19/20 7:34 PM, Marek Polacek wrote:
On Mon, May 18, 2020 at 03:51:36PM -0400, Jason Merrill wrote:On 5/16/20 6:34 PM, Marek Polacek wrote:Since GCC 9, C++17 support is no longer experimental. It was too late to change the default C++ dialect to C++17 in GCC 10, but I think now it's time to pull the trigger (C++14 was made the default in GCC 6.1). We're still missing two C++17 library features, but that shouldn't stop us. See <https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2017> and <https://gcc.gnu.org/projects/cxx-status.html#cxx17> for the C++17 status.I won't list all C++17 features here, but just a few heads-up: - trigraphs were removed (hardly anyone cares, unless your keyboard is missing the # key), - operator++(bool) was removed (so some tests now run in C++14 and down only), - the keyword register was removed (some legacy code might trip on this), - noexcept specification is now part of the type system and C++17 does not allow dynamic exception specifications anymore (the empty throw specification is still available, but it is deprecated), - the evaluation order rules are different in C++17, - static constexpr data members are now implicitly inline (which makes them definitions), - C++17 requires guaranteed copy elision, meaning that a copy/move constructor call might be elided completely. That means that if something relied on a constructor being instantiated via e.g. copying a function parameter, it might now fail. Jakub, the last point is actually what I encountered in for-27.C and it looks like an OpenMP issue, in that it wrongly depends on an implicit instantiation. Am I mistaken? Due to the 'register' removal, this patch depends on the regenerated cfns.h version I posted earlier today. I'll post an update for cxx-status.html and add a new caveat to changes.html once this is in. Bootstrapped/regtested on x86_64-pc-linux-gnu, aarch64-unknown-linux-gnu, and powerpc64le-unknown-linux-gnu. Ok for trunk? * doc/invoke.texi (C Dialect Options): Adjust -std default for C++. * doc/standards.texi (C Language): Correct the default dialect. (C++ Language): Update the default for C++ to gnu++17. * c-opts.c (c_common_init_options): Default to gnu++17. * c-c++-common/torture/vector-subscript-3.c: Remove the register keywords. * g++.dg/cpp1z/attributes-enum-1a.C: Update for C++17. * g++.dg/cpp1z/fold7a.C: Likewise. * g++.dg/cpp1z/nontype3a.C: Likewise. * g++.dg/cpp1z/utf8-2a.C: Likewise. * g++.dg/parse/error11.C: Use c++14_down. * g++.dg/torture/pr34850.C: Add -Wno-attribute-warning. * g++.dg/torture/pr49394.C: Add dg-warning. * g++.dg/torture/pr82154.C: Use -std=c++14. * g++.dg/ubsan/pr85029.C: Use -Wno-register. * g++.dg/ubsan/vptr-12.C: Use -fstrong-eval-order=some. * lib/target-supports.exp: Set to C++17. * obj-c++.dg/try-catch-9.mm: Use -Wno-register. * testsuite/libgomp.c++/atomic-3.C: Use -std=gnu++14. * testsuite/libgomp.c++/for-27.C: Explicitly instantiate the copy constructor for I<int>. --- gcc/c-family/c-opts.c | 4 ++-- gcc/doc/invoke.texi | 2 +- gcc/doc/standards.texi | 4 ++-- gcc/testsuite/c-c++-common/torture/vector-subscript-3.c | 6 +++--- gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C | 4 ++-- gcc/testsuite/g++.dg/cpp1z/fold7a.C | 4 ++-- gcc/testsuite/g++.dg/cpp1z/nontype3a.C | 4 ++-- gcc/testsuite/g++.dg/cpp1z/utf8-2a.C | 4 ++-- gcc/testsuite/g++.dg/parse/error11.C | 5 +++-- gcc/testsuite/g++.dg/torture/pr34850.C | 2 +- gcc/testsuite/g++.dg/torture/pr49394.C | 2 +- gcc/testsuite/g++.dg/torture/pr82154.C | 3 ++- gcc/testsuite/g++.dg/ubsan/pr85029.C | 2 +- gcc/testsuite/g++.dg/ubsan/vptr-12.C | 2 +- gcc/testsuite/lib/target-supports.exp | 2 +- gcc/testsuite/obj-c++.dg/try-catch-9.mm | 2 +- libgomp/testsuite/libgomp.c++/atomic-3.C | 3 ++- libgomp/testsuite/libgomp.c++/for-27.C | 6 ++++++ 18 files changed, 35 insertions(+), 26 deletions(-) diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c index 7695e88c130..5b266c06f3b 100644 --- a/gcc/c-family/c-opts.c +++ b/gcc/c-family/c-opts.c @@ -256,9 +256,9 @@ c_common_init_options (unsigned int decoded_options_count, } } - /* Set C++ standard to C++14 if not specified on the command line. */ + /* Set C++ standard to C++17 if not specified on the command line. */ if (c_dialect_cxx ()) - set_std_cxx14 (/*ISO*/false); + set_std_cxx17 (/*ISO*/false); global_dc->colorize_source_p = true; } diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 850aeac033d..97e13421323 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -2057,7 +2057,6 @@ The name @samp{c++1y} is deprecated. @item gnu++14 @itemx gnu++1y GNU dialect of @option{-std=c++14}. -This is the default for C++ code. The name @samp{gnu++1y} is deprecated. @item c++17 @@ -2068,6 +2067,7 @@ The name @samp{c++1z} is deprecated. @item gnu++17 @itemx gnu++1z GNU dialect of @option{-std=c++17}. +This is the default for C++ code. The name @samp{gnu++1z} is deprecated. @item c++20 diff --git a/gcc/doc/standards.texi b/gcc/doc/standards.texi index f39d8b378f1..fc5016028dd 100644 --- a/gcc/doc/standards.texi +++ b/gcc/doc/standards.texi @@ -130,7 +130,7 @@ select an extended version of the C language explicitly with extensions). The default, if no C language dialect options are given, -is @option{-std=gnu11}. +is @option{-std=gnu17}.I don't think you mean to change the default C dialect.The current default C dialect already is gnu17, here I was just correcting that as a drive-by. I can commit it separately if you prefer.The ISO C standard defines (in clause 4) two classes of conforming implementation. A @dfn{conforming hosted implementation} supports the @@ -246,7 +246,7 @@ select an extended version of the C++ language explicitly with @option{-std=gnu++17} (for C++17 with GNU extensions). The default, if -no C++ language dialect options are given, is @option{-std=gnu++14}. +no C++ language dialect options are given, is @option{-std=gnu++17}. @section Objective-C and Objective-C++ Languages @cindex Objective-C diff --git a/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c b/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c index bb5c91485d7..12779af5438 100644 --- a/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c +++ b/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c @@ -12,9 +12,9 @@ struct vec_s { int main () { - register short vector v0 = {1,2,3,4,5,6,7}; - register myvec_t v1 = {1,2,3,4,5,6,7}; - register struct vec_s v2; + short vector v0 = {1,2,3,4,5,6,7}; + myvec_t v1 = {1,2,3,4,5,6,7}; + struct vec_s v2;I'd be careful about changing a c-c++-common torture test like this. Maybe #define away register for C++17 and up, or add -Wno-register in C++ mode like you do for other testcases?Done.v2.member = v1; diff --git a/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C b/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C index aacfac875b1..4d7e547920f 100644 --- a/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C +++ b/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C @@ -1,5 +1,5 @@ -// This macro should not be defined without -std=c++17. +// This macro should be defined with -std=c++17. -#ifdef __cpp_enumerator_attributes +#ifndef __cpp_enumerator_attributesYou're turning this file into the same test as attributes-enum-1.C, and it's intended to be the complementary test. Instead, restrict the test to pre-C++17.Indeed, that was sloppy. This test (and the other) is now c++14_down. It was annoying to find out that only adding the target didn't suffice -- it seems that dejagnu's proc check-flags happily accepts -std flags in comments too, so it thought that we specified -std=c++17 and it didn't run the test in any other mode. Fixed by tweaking the comment...#error __cpp_enumerator_attributes defined #endif diff --git a/gcc/testsuite/g++.dg/cpp1z/fold7a.C b/gcc/testsuite/g++.dg/cpp1z/fold7a.C index 5c782ff0969..530741d3907 100644 --- a/gcc/testsuite/g++.dg/cpp1z/fold7a.C +++ b/gcc/testsuite/g++.dg/cpp1z/fold7a.C @@ -1,5 +1,5 @@ -// This macro should not be defined without -std=c++17. +// This macro should be defined with -std=c++17. -#ifdef __cpp_fold_expressions +#ifndef __cpp_fold_expressionsLikewise.^#error __cpp_fold_expressions defined #endif diff --git a/gcc/testsuite/g++.dg/cpp1z/nontype3a.C b/gcc/testsuite/g++.dg/cpp1z/nontype3a.C index a704e5045b6..7b640e551b6 100644 --- a/gcc/testsuite/g++.dg/cpp1z/nontype3a.C +++ b/gcc/testsuite/g++.dg/cpp1z/nontype3a.C @@ -1,5 +1,5 @@ -// This macro should not be defined without -std=c++17. +// This macro should be defined with -std=c++17. -#ifdef __cpp_nontype_template_args +#ifndef __cpp_nontype_template_argsLikewise.^#error __cpp_nontype_template_args defined #endif diff --git a/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C b/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C index 0e243d68a75..c4a8f46fb7d 100644 --- a/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C +++ b/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C @@ -1,5 +1,5 @@ -// This macro should not be 201411 without -std=c++17. +// This macro should be 201411 with -std=c++17. -#if __cpp_unicode_characters == 201411 +#if __cpp_unicode_characters != 201411Likewise.^#error Wrong value for __cpp_unicode_characters #endif diff --git a/gcc/testsuite/g++.dg/parse/error11.C b/gcc/testsuite/g++.dg/parse/error11.C index 1a49d6edb12..4e2a7f8b75f 100644 --- a/gcc/testsuite/g++.dg/parse/error11.C +++ b/gcc/testsuite/g++.dg/parse/error11.C @@ -1,5 +1,6 @@ -// { dg-do compile } -// { dg-options "-fshow-column" }" +// { dg-do compile { target c++14_down } } +// C++17 removed trigraphs.There are no trigraphs in this testcase, and digraphs are still part of C++20.True. In C++17 we issue slightly different diagnostics for lines 51 and 52, and I thought it was so because trigraphs had been removed.
I think it's because of CTAD making a template-name without arguments potentially valid.
I've updated the expected error messages instead. Is that acceptable?
I'm not sure they need to be so specific, but that's fine.
+// { dg-options "-fshow-column" } // Origin: Giovanni Bajo <giovannibajo at gcc dot gnu dot org> // Try to find out when the digraph '<:' is used as a mistake, and parse it // correctly to avoid cascaded errors. diff --git a/gcc/testsuite/g++.dg/torture/pr34850.C b/gcc/testsuite/g++.dg/torture/pr34850.C index c4d808c5a0d..59dd5dfde7d 100644 --- a/gcc/testsuite/g++.dg/torture/pr34850.C +++ b/gcc/testsuite/g++.dg/torture/pr34850.C @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */ -/* { dg-options "-ffat-lto-objects -Wno-return-type" } */ +/* { dg-options "-ffat-lto-objects -Wno-return-type -Wno-attribute-warning" } */Why?Sorry, this was non-obvious. This boils down to void __warn_memset_zero_len() __attribute__((__warning__(""))); long b; void foo() throw() { if (__builtin_constant_p(b)) __warn_memset_zero_len(); } int bar() { foo(); } In C++17, with -O2, we give t.C:6:27: warning: call to '__warn_memset_zero_len' declared with attribute warning: [-Wattribute-warning] 6 | __warn_memset_zero_len(); while in C++14 we don't. We behave differently due to... 26006 /* In C++17, throw() is equivalent to noexcept (true). throw() 26007 is deprecated in C++11 and above as well, but is still widely used, 26008 so don't warn about it yet. */ 26009 else if (cxx_dialect >= cxx17) 26010 type_id_list = noexcept_true_spec; 26011 else 26012 type_id_list = empty_except_spec; ...and different optimizations based on that. In C++17, we inline foo, and then CCP folds the __builtin_constant_p call and we end up with bar () { __warn_memset_zero_len (); __builtin_unreachable (); } and since __warn_memset_zero_len is marked with the warning attribute, expand_expr_real_1 warns. In C++14 we don't inline foo, but VRP removes the code inside foo, DCE then elides the call to foo completely, and we end up without the call to __warn_memset_zero_len so we don't warn. Note that bar misses a return statement, which can be UB at runtime. This doesn't strike me as a C++ FE issue.typedef unsigned char uint8_t; typedef unsigned int uint32_t; diff --git a/gcc/testsuite/g++.dg/torture/pr49394.C b/gcc/testsuite/g++.dg/torture/pr49394.C index 7bd8fd4dc72..32e1a98ce05 100644 --- a/gcc/testsuite/g++.dg/torture/pr49394.C +++ b/gcc/testsuite/g++.dg/torture/pr49394.C @@ -10,7 +10,7 @@ struct Mutex #endif { if (locked) - throw 0; + throw 0; // { dg-warning ".throw. will always call .terminate." "" { target c++17 } }Instead, the destructor should be noexcept(false) in C++17 and up.Fixed.} void lock () { diff --git a/gcc/testsuite/g++.dg/torture/pr82154.C b/gcc/testsuite/g++.dg/torture/pr82154.C index e229c3e640e..698340d8c65 100644 --- a/gcc/testsuite/g++.dg/torture/pr82154.C +++ b/gcc/testsuite/g++.dg/torture/pr82154.C @@ -1,5 +1,6 @@ // { dg-do compile } -// { dg-additional-options "-Wno-deprecated" } +// { dg-additional-options "-std=c++14 -Wno-deprecated" } +// C++17 does not allow dynamic exception specification. namespace a { int b; diff --git a/gcc/testsuite/g++.dg/ubsan/pr85029.C b/gcc/testsuite/g++.dg/ubsan/pr85029.C index 07472af16a5..836ce69cc15 100644 --- a/gcc/testsuite/g++.dg/ubsan/pr85029.C +++ b/gcc/testsuite/g++.dg/ubsan/pr85029.C @@ -1,7 +1,7 @@ // PR sanitizer/85029 // { dg-do compile } // { dg-skip-if "" { *-*-* } { "-flto -fno-fat-lto-objects" } } -// { dg-options "-fsanitize=undefined" } +// { dg-options "-fsanitize=undefined -Wno-register" } struct B { virtual B bar (); diff --git a/gcc/testsuite/g++.dg/ubsan/vptr-12.C b/gcc/testsuite/g++.dg/ubsan/vptr-12.C index f23bbc3fd10..ce57ba87db0 100644 --- a/gcc/testsuite/g++.dg/ubsan/vptr-12.C +++ b/gcc/testsuite/g++.dg/ubsan/vptr-12.C @@ -1,6 +1,6 @@ // { dg-do run } // { dg-shouldfail "ubsan" } -// { dg-options "-fsanitize=vptr -fno-sanitize-recover=vptr" } +// { dg-options "-fsanitize=vptr -fno-sanitize-recover=vptr -fstrong-eval-order=some" }Why? I can't see anything in this testcase that should be affected by -fstrong-eval-order.I think this points to a bug; I'd been meaning to come back to it but apparently I never did. I've investigated more now and opened https://gcc.gnu.org/PR95221 along with my initial analysis. I'm uncertain if this one should be a blocker for the default change -- valid code should never hit it, after all --, though...
Fixed, you shouldn't need changes to the ubsan tests anymore.
struct MyClass { diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp index 3e91a81dd5a..4191600fcd9 100644 --- a/gcc/testsuite/lib/target-supports.exp +++ b/gcc/testsuite/lib/target-supports.exp @@ -9018,7 +9018,7 @@ proc check_effective_target_c++ { } { return 0 } -set cxx_default "c++14" +set cxx_default "c++17" # Check whether the current active language standard supports the features # of C++11/C++14 by checking for the presence of one of the -std flags. # This assumes that the default for the compiler is $cxx_default, and that diff --git a/gcc/testsuite/obj-c++.dg/try-catch-9.mm b/gcc/testsuite/obj-c++.dg/try-catch-9.mm index 73c7c991709..b2dc61b9989 100644 --- a/gcc/testsuite/obj-c++.dg/try-catch-9.mm +++ b/gcc/testsuite/obj-c++.dg/try-catch-9.mm @@ -6,7 +6,7 @@ /* { dg-xfail-run-if "PR23616" { *-*-* } { "-fgnu-runtime" } { "-fnext-runtime" } } */ /* { dg-xfail-if "Needs OBJC2 ABI" { *-*-darwin* && { lp64 && { ! objc2 } } } { "-fnext-runtime" "-fgnu-runtime" } { "" } } /* { dg-prune-output ".*internal compiler error.*" } */ -/* { dg-options "-fobjc-exceptions -O2" } */ +/* { dg-options "-fobjc-exceptions -O2 -Wno-register" } */ #include "../objc-obj-c++-shared/TestsuiteObject.m" #include <stdlib.h> diff --git a/libgomp/testsuite/libgomp.c++/atomic-3.C b/libgomp/testsuite/libgomp.c++/atomic-3.C index f957b2fece5..c02532d3206 100644 --- a/libgomp/testsuite/libgomp.c++/atomic-3.C +++ b/libgomp/testsuite/libgomp.c++/atomic-3.C @@ -1,5 +1,6 @@ // { dg-do run } -// { dg-options "-Wno-deprecated" } +// C++17 forbids ++ on bool. +// { dg-options "-Wno-deprecated -std=gnu++14" } extern "C" void abort (void); bool v, x1, x2, x3, x4, x5, x6; diff --git a/libgomp/testsuite/libgomp.c++/for-27.C b/libgomp/testsuite/libgomp.c++/for-27.C index 7dca4305f85..d286346e63a 100644 --- a/libgomp/testsuite/libgomp.c++/for-27.C +++ b/libgomp/testsuite/libgomp.c++/for-27.C @@ -151,6 +151,12 @@ f4 (const I<int> &x, const I<int> &y) else if (results[i]) \ abort () +// FIXME: OpenMP seems to count on this being instantiated; the copy +// constructor is called in functions fn2/fn3/fn4. But in C++17 we +// elide this copy constructor, so it's never been instantiated. For +// now instantiate it explicitly.This sounds like a bug that needs to be fixed before the default can change. I guess the openmp code needs to mark_used the copy constructor or the like....this makes sense. I've opened https://gcc.gnu.org/PR95197 to handle this; I think either Jakub or I should be able to fix it before long. Bootstrapped/regtested on x86_64-pc-linux-gnu.
OK without the ubsan test changes once 95197 is fixed.
-- >8 -- Since GCC 9, C++17 support is no longer experimental. It was too late to change the default C++ dialect to C++17 in GCC 10, but I think now it's time to pull the trigger (C++14 was made the default in GCC 6.1). We're still missing two C++17 library features, but that shouldn't stop us. See <https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2017> and <https://gcc.gnu.org/projects/cxx-status.html#cxx17> for the C++17 status. I won't list all C++17 features here, but just a few heads-up: - trigraphs were removed (hardly anyone cares, unless your keyboard is missing the # key), - operator++(bool) was removed (so some tests now run in C++14 and down only), - the keyword register was removed (some legacy code might trip on this), - noexcept specification is now part of the type system and C++17 does not allow dynamic exception specifications anymore (the empty throw specification is still available, but it is deprecated), - the evaluation order rules are different in C++17, - static constexpr data members are now implicitly inline (which makes them definitions), - C++17 requires guaranteed copy elision, meaning that a copy/move constructor call might be elided completely. That means that if something relied on a constructor being instantiated via e.g. copying a function parameter, it might now fail. I'll post an update for cxx-status.html and add a new caveat to changes.html once this is in. * doc/invoke.texi (C Dialect Options): Adjust -std default for C++. * doc/standards.texi (C Language): Correct the default dialect. (C++ Language): Update the default for C++ to gnu++17. * c-opts.c (c_common_init_options): Default to gnu++17. * c-c++-common/torture/vector-subscript-3.c: In C++17, define away the keyword register. * g++.dg/cpp1z/attributes-enum-1a.C: Only run pre-C++17. * g++.dg/cpp1z/fold7a.C: Likewise. * g++.dg/cpp1z/nontype3a.C: Likewise. * g++.dg/cpp1z/utf8-2a.C: Likewise. * g++.dg/parse/error11.C: Update expected diagnostics for C++17. * g++.dg/torture/pr34850.C: Add -Wno-attribute-warning. * g++.dg/torture/pr49394.C: In C++17, use noexcept(false). * g++.dg/torture/pr82154.C: Use -std=c++14. * g++.dg/ubsan/pr85029.C: Use -Wno-register. * g++.dg/ubsan/vptr-12.C: Use -fstrong-eval-order=some. Adjust dg-output. * lib/target-supports.exp: Set to C++17. * obj-c++.dg/try-catch-9.mm: Use -Wno-register. * testsuite/libgomp.c++/atomic-3.C: Use -std=gnu++14. --- gcc/c-family/c-opts.c | 4 ++-- gcc/doc/invoke.texi | 2 +- gcc/doc/standards.texi | 4 ++-- .../c-c++-common/torture/vector-subscript-3.c | 3 +++ .../g++.dg/cpp1z/attributes-enum-1a.C | 3 ++- gcc/testsuite/g++.dg/cpp1z/fold7a.C | 3 ++- gcc/testsuite/g++.dg/cpp1z/nontype3a.C | 3 ++- gcc/testsuite/g++.dg/cpp1z/utf8-2a.C | 3 ++- gcc/testsuite/g++.dg/parse/error11.C | 18 +++++++++++------- gcc/testsuite/g++.dg/torture/pr34850.C | 2 +- gcc/testsuite/g++.dg/torture/pr49394.C | 2 ++ gcc/testsuite/g++.dg/torture/pr82154.C | 3 ++- gcc/testsuite/g++.dg/ubsan/pr85029.C | 2 +- gcc/testsuite/g++.dg/ubsan/vptr-12.C | 5 +++-- gcc/testsuite/lib/target-supports.exp | 2 +- gcc/testsuite/obj-c++.dg/try-catch-9.mm | 2 +- libgomp/testsuite/libgomp.c++/atomic-3.C | 3 ++- 17 files changed, 40 insertions(+), 24 deletions(-) diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c index 7695e88c130..5b266c06f3b 100644 --- a/gcc/c-family/c-opts.c +++ b/gcc/c-family/c-opts.c @@ -256,9 +256,9 @@ c_common_init_options (unsigned int decoded_options_count, } }- /* Set C++ standard to C++14 if not specified on the command line. */+ /* Set C++ standard to C++17 if not specified on the command line. */ if (c_dialect_cxx ()) - set_std_cxx14 (/*ISO*/false); + set_std_cxx17 (/*ISO*/false);global_dc->colorize_source_p = true;} diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 7217e27151d..c1acb8a70c2 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -2057,7 +2057,6 @@ The name @samp{c++1y} is deprecated. @item gnu++14 @itemx gnu++1y GNU dialect of @option{-std=c++14}. -This is the default for C++ code. The name @samp{gnu++1y} is deprecated.@item c++17@@ -2068,6 +2067,7 @@ The name @samp{c++1z} is deprecated. @item gnu++17 @itemx gnu++1z GNU dialect of @option{-std=c++17}. +This is the default for C++ code. The name @samp{gnu++1z} is deprecated.@item c++20diff --git a/gcc/doc/standards.texi b/gcc/doc/standards.texi index f39d8b378f1..fc5016028dd 100644 --- a/gcc/doc/standards.texi +++ b/gcc/doc/standards.texi @@ -130,7 +130,7 @@ select an extended version of the C language explicitly with extensions).The default, if no C language dialect options are given,-is @option{-std=gnu11}. +is @option{-std=gnu17}.The ISO C standard defines (in clause 4) two classes of conformingimplementation. A @dfn{conforming hosted implementation} supports the @@ -246,7 +246,7 @@ select an extended version of the C++ language explicitly with @option{-std=gnu++17} (for C++17 with GNU extensions).The default, if-no C++ language dialect options are given, is @option{-std=gnu++14}. +no C++ language dialect options are given, is @option{-std=gnu++17}.@section Objective-C and Objective-C++ Languages@cindex Objective-C diff --git a/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c b/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c index bb5c91485d7..05d24f49011 100644 --- a/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c +++ b/gcc/testsuite/c-c++-common/torture/vector-subscript-3.c @@ -10,6 +10,9 @@ struct vec_s { vector short member; };+#if defined(__cplusplus) && __cplusplus >= 201703L+#define register /* nothing */ +#endifint main () {register short vector v0 = {1,2,3,4,5,6,7}; diff --git a/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C b/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C index aacfac875b1..20f0b1d8876 100644 --- a/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C +++ b/gcc/testsuite/g++.dg/cpp1z/attributes-enum-1a.C @@ -1,4 +1,5 @@ -// This macro should not be defined without -std=c++17. +// { dg-do compile { target c++14_down } } +// This macro should not be defined without c++17.#ifdef __cpp_enumerator_attributes#error __cpp_enumerator_attributes defined diff --git a/gcc/testsuite/g++.dg/cpp1z/fold7a.C b/gcc/testsuite/g++.dg/cpp1z/fold7a.C index 5c782ff0969..8cca8792709 100644 --- a/gcc/testsuite/g++.dg/cpp1z/fold7a.C +++ b/gcc/testsuite/g++.dg/cpp1z/fold7a.C @@ -1,4 +1,5 @@ -// This macro should not be defined without -std=c++17. +// { dg-do compile { target c++14_down } } +// This macro should not be defined without c++17.#ifdef __cpp_fold_expressions#error __cpp_fold_expressions defined diff --git a/gcc/testsuite/g++.dg/cpp1z/nontype3a.C b/gcc/testsuite/g++.dg/cpp1z/nontype3a.C index a704e5045b6..b3ffe037904 100644 --- a/gcc/testsuite/g++.dg/cpp1z/nontype3a.C +++ b/gcc/testsuite/g++.dg/cpp1z/nontype3a.C @@ -1,4 +1,5 @@ -// This macro should not be defined without -std=c++17. +// { dg-do compile { target c++14_down } } +// This macro should not be defined without c++17.#ifdef __cpp_nontype_template_args#error __cpp_nontype_template_args defined diff --git a/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C b/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C index 0e243d68a75..b2a99a99023 100644 --- a/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C +++ b/gcc/testsuite/g++.dg/cpp1z/utf8-2a.C @@ -1,4 +1,5 @@ -// This macro should not be 201411 without -std=c++17. +// { dg-do compile { target c++14_down } } +// This macro should not be 201411 without c++17.#if __cpp_unicode_characters == 201411#error Wrong value for __cpp_unicode_characters diff --git a/gcc/testsuite/g++.dg/parse/error11.C b/gcc/testsuite/g++.dg/parse/error11.C index 1a49d6edb12..4baf97e531d 100644 --- a/gcc/testsuite/g++.dg/parse/error11.C +++ b/gcc/testsuite/g++.dg/parse/error11.C @@ -1,5 +1,5 @@ // { dg-do compile } -// { dg-options "-fshow-column" }" +// { dg-options "-fshow-column" } // Origin: Giovanni Bajo <giovannibajo at gcc dot gnu dot org> // Try to find out when the digraph '<:' is used as a mistake, and parse it // correctly to avoid cascaded errors. @@ -50,12 +50,16 @@ void func(void) // the special error message. Foo<: :B> k2; // { dg-bogus "cannot begin|alternate spelling" "smart error should not be triggered here" } Foo[:B> k1; // { dg-bogus "cannot begin|alternate spelling" "smart error should not be triggered here" } -// { dg-error "6:missing template arguments before" "template" { target *-*-* } 51 } -// { dg-error "9:expected primary-expression before ':' token" "primary" { target *-*-* } 51 } -// { dg-error "8:expected '\]' before ':' token" "backslash" { target *-*-* } 51 } -// { dg-error "6:missing template arguments before" "template" { target *-*-* } 52 } -// { dg-error "7:expected primary-expression before ':' token" "primary" { target *-*-* } 52 } -// { dg-error "7:expected '\]' before ':' token" "backslash" { target *-*-* } 52 } +// { dg-error "6:missing template arguments before" "template" { target c++14_down } .-2 } +// { dg-error "9:expected primary-expression before ':' token" "primary" { target c++14_down } .-3 } +// { dg-error "8:expected '\]' before ':' token" "backslash" { target c++14_down } .-4 } +// { dg-error "6:missing template arguments before" "template" { target c++14_down } .-4 } +// { dg-error "7:expected primary-expression before ':' token" "primary" { target c++14_down } .-5 } +// { dg-error "7:expected '\]' before ':' token" "backslash" { target c++14_down } .-6 } +// { dg-error "9:expected identifier" "" { target c++17 } .-8 } +// { dg-error "8:expected" "" { target c++17 } .-9 } +// { dg-error "7:expected identifier" "" { target c++17 } .-9 } +// { dg-error "7:expected" "" { target c++17 } .-10 } // int Foo[2]; Foo[::value] = 0; diff --git a/gcc/testsuite/g++.dg/torture/pr34850.C b/gcc/testsuite/g++.dg/torture/pr34850.C index c4d808c5a0d..59dd5dfde7d 100644 --- a/gcc/testsuite/g++.dg/torture/pr34850.C +++ b/gcc/testsuite/g++.dg/torture/pr34850.C @@ -1,6 +1,6 @@ /* { dg-do compile } */ /* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */ -/* { dg-options "-ffat-lto-objects -Wno-return-type" } */ +/* { dg-options "-ffat-lto-objects -Wno-return-type -Wno-attribute-warning" } */typedef unsigned char uint8_t;typedef unsigned int uint32_t; diff --git a/gcc/testsuite/g++.dg/torture/pr49394.C b/gcc/testsuite/g++.dg/torture/pr49394.C index 7bd8fd4dc72..75901a5d668 100644 --- a/gcc/testsuite/g++.dg/torture/pr49394.C +++ b/gcc/testsuite/g++.dg/torture/pr49394.C @@ -7,6 +7,8 @@ struct Mutex ~Mutex () #if __cplusplus <= 201402L throw(int) // { dg-warning "deprecated" "" { target { c++11 && { ! c++17 } } } } +#else + noexcept(false) #endif { if (locked) diff --git a/gcc/testsuite/g++.dg/torture/pr82154.C b/gcc/testsuite/g++.dg/torture/pr82154.C index e229c3e640e..698340d8c65 100644 --- a/gcc/testsuite/g++.dg/torture/pr82154.C +++ b/gcc/testsuite/g++.dg/torture/pr82154.C @@ -1,5 +1,6 @@ // { dg-do compile } -// { dg-additional-options "-Wno-deprecated" } +// { dg-additional-options "-std=c++14 -Wno-deprecated" } +// C++17 does not allow dynamic exception specification.namespace a {int b; diff --git a/gcc/testsuite/g++.dg/ubsan/pr85029.C b/gcc/testsuite/g++.dg/ubsan/pr85029.C index 07472af16a5..836ce69cc15 100644 --- a/gcc/testsuite/g++.dg/ubsan/pr85029.C +++ b/gcc/testsuite/g++.dg/ubsan/pr85029.C @@ -1,7 +1,7 @@ // PR sanitizer/85029 // { dg-do compile } // { dg-skip-if "" { *-*-* } { "-flto -fno-fat-lto-objects" } } -// { dg-options "-fsanitize=undefined" } +// { dg-options "-fsanitize=undefined -Wno-register" }struct B {virtual B bar (); diff --git a/gcc/testsuite/g++.dg/ubsan/vptr-12.C b/gcc/testsuite/g++.dg/ubsan/vptr-12.C index f23bbc3fd10..79d4290754e 100644 --- a/gcc/testsuite/g++.dg/ubsan/vptr-12.C +++ b/gcc/testsuite/g++.dg/ubsan/vptr-12.C @@ -1,6 +1,7 @@ // { dg-do run } // { dg-shouldfail "ubsan" } -// { dg-options "-fsanitize=vptr -fno-sanitize-recover=vptr" } +// { dg-options "-fsanitize=vptr -fno-sanitize-recover=vptr -fstrong-eval-order=some" } +// FIXME: See PR95221 for why we use a specific eval order.struct MyClass{ @@ -18,5 +19,5 @@ main () return 0; }-// { dg-output "\[^\n\r]*vptr-12.C:16:\[0-9]*: runtime error: member call on address 0x\[0-9a-fA-F]* which does not point to an object of type 'MyClass'(\n|\r\n|\r)" }+// { dg-output "\[^\n\r]*vptr-12.C:17:\[0-9]*: runtime error: member call on address 0x\[0-9a-fA-F]* which does not point to an object of type 'MyClass'(\n|\r\n|\r)" } // { dg-output "0x\[0-9a-fA-F]*: note: object has invalid vptr" } diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp index b335108358d..58638a3e189 100644 --- a/gcc/testsuite/lib/target-supports.exp +++ b/gcc/testsuite/lib/target-supports.exp @@ -9046,7 +9046,7 @@ proc check_effective_target_c++ { } { return 0 }-set cxx_default "c++14"+set cxx_default "c++17" # Check whether the current active language standard supports the features # of C++11/C++14 by checking for the presence of one of the -std flags. # This assumes that the default for the compiler is $cxx_default, and that diff --git a/gcc/testsuite/obj-c++.dg/try-catch-9.mm b/gcc/testsuite/obj-c++.dg/try-catch-9.mm index 73c7c991709..b2dc61b9989 100644 --- a/gcc/testsuite/obj-c++.dg/try-catch-9.mm +++ b/gcc/testsuite/obj-c++.dg/try-catch-9.mm @@ -6,7 +6,7 @@ /* { dg-xfail-run-if "PR23616" { *-*-* } { "-fgnu-runtime" } { "-fnext-runtime" } } */ /* { dg-xfail-if "Needs OBJC2 ABI" { *-*-darwin* && { lp64 && { ! objc2 } } } { "-fnext-runtime" "-fgnu-runtime" } { "" } } /* { dg-prune-output ".*internal compiler error.*" } */ -/* { dg-options "-fobjc-exceptions -O2" } */ +/* { dg-options "-fobjc-exceptions -O2 -Wno-register" } */#include "../objc-obj-c++-shared/TestsuiteObject.m"#include <stdlib.h> diff --git a/libgomp/testsuite/libgomp.c++/atomic-3.C b/libgomp/testsuite/libgomp.c++/atomic-3.C index f957b2fece5..c02532d3206 100644 --- a/libgomp/testsuite/libgomp.c++/atomic-3.C +++ b/libgomp/testsuite/libgomp.c++/atomic-3.C @@ -1,5 +1,6 @@ // { dg-do run } -// { dg-options "-Wno-deprecated" } +// C++17 forbids ++ on bool. +// { dg-options "-Wno-deprecated -std=gnu++14" }extern "C" void abort (void);bool v, x1, x2, x3, x4, x5, x6; base-commit: a2d196e75cef95c2b70734ad02e94f9da0e769fe
