b04445d4a8
C++20 isn't final quite yet, but all that remains is formalities, so let's go ahead and change all the references. I think for the next C++ standard we can just call it C++23 rather than C++2b, since the committee has been consistent about time-based releases rather than feature-based. gcc/c-family/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * c.opt (std=c++20): Make c++2a the alias. (std=gnu++20): Likewise. * c-common.h (cxx_dialect): Change cxx2a to cxx20. * c-opts.c: Adjust. * c-cppbuiltin.c: Adjust. * c-ubsan.c: Adjust. * c-warn.c: Adjust. gcc/cp/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * call.c, class.c, constexpr.c, constraint.cc, decl.c, init.c, lambda.c, lex.c, method.c, name-lookup.c, parser.c, pt.c, tree.c, typeck2.c: Change cxx2a to cxx20. libcpp/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * include/cpplib.h (enum c_lang): Change CXX2A to CXX20. * init.c, lex.c: Adjust.
100 lines
1.7 KiB
C
100 lines
1.7 KiB
C
// PR c++/91353 - P1331R2: Allow trivial default init in constexpr contexts.
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// { dg-do compile { target c++20 } }
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// Test basic use.
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struct S {
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int i;
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constexpr S(bool b) {
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if (b)
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i = 42;
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}
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};
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constexpr S s1(true);
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constexpr S s2(false); // { dg-error "not a constant expression" }
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constexpr int
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fn1 (int x)
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{
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int a;
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a = 5;
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return x + a;
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}
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static_assert (fn1 (2) == 7);
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constexpr int
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fn2 (int x)
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{
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const int a; // { dg-error "uninitialized .const a." }
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constexpr int b; // { dg-error "uninitialized .const b." }
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return x;
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}
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constexpr int
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fn3 (int x)
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{
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int a; // { dg-message ".int a. is not const" }
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return x + a; // { dg-error "the value of .a. is not usable in a constant expression" }
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}
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constexpr int a = fn3 (5); // { dg-message "in .constexpr. expansion of" }
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constexpr int
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fn4 ()
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{
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struct S { int a = -5; int b; } s;
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return s.a;
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}
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static_assert (fn4 () == -5);
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constexpr int
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fn5 ()
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{
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struct S { int a = 9; int b; } s;
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return s.b;
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}
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constexpr int b = fn5 (); // { dg-error "accessing uninitialized member" }
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// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
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constexpr int
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fn6 ()
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{
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int a;
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return 42;
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}
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static_assert (fn6 () == 42);
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constexpr int
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fn7 (bool b)
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{
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int a; // { dg-message ".int a. is not const" }
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if (b)
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a = 42;
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return a;
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}
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static_assert (fn7 (true) == 42);
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static_assert (fn7 (false) == 42); // { dg-error "non-constant condition|the value of .a. is not usable" }
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// { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
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constexpr int
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fn8 (int n)
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{
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int r;
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switch (n)
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{
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case 1:
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r = n;
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return r;
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case 42:
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r = n;
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return r;
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}
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}
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static_assert (fn8 (1) == 1);
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static_assert (fn8 (42) == 42);
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