I noticed that C++14 [basic.types] says that "a type is a literal type if it is: void, [...]". Yet our literal_type_p doesn't consider void type as a literal type. The following is an attempt to fix that along with a testcase. It seems that void was only added in C++14, so check for cxx14 as well.
Bootstrapped/regtested on ppc64-linux, ok for trunk? 2014-11-21 Marek Polacek <pola...@redhat.com> * constexpr.c (literal_type_p): Return true for void type in C++14. * g++.dg/cpp0x/constexpr-function2.C: Limit dg-error to C++11. * g++.dg/cpp0x/constexpr-neg1.C: Likewise. * g++.dg/cpp1y/constexpr-void1.C: New test. diff --git gcc/cp/constexpr.c gcc/cp/constexpr.c index 2678223..0a258cf 100644 --- gcc/cp/constexpr.c +++ gcc/cp/constexpr.c @@ -59,7 +59,8 @@ literal_type_p (tree t) { if (SCALAR_TYPE_P (t) || TREE_CODE (t) == VECTOR_TYPE - || TREE_CODE (t) == REFERENCE_TYPE) + || TREE_CODE (t) == REFERENCE_TYPE + || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) return true; if (CLASS_TYPE_P (t)) { diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-function2.C gcc/testsuite/g++.dg/cpp0x/constexpr-function2.C index 8c51c9d..95ee244 100644 --- gcc/testsuite/g++.dg/cpp0x/constexpr-function2.C +++ gcc/testsuite/g++.dg/cpp0x/constexpr-function2.C @@ -23,7 +23,7 @@ constexpr int area = squarei(side); // { dg-error "side|argument" } int next(constexpr int x) // { dg-error "parameter" } { return x + 1; } -constexpr void f(int x) // { dg-error "return type .void" } +constexpr void f(int x) // { dg-error "return type .void" "" { target c++11_only } } { /* ... */ } constexpr int prev(int x) diff --git gcc/testsuite/g++.dg/cpp0x/constexpr-neg1.C gcc/testsuite/g++.dg/cpp0x/constexpr-neg1.C index 35f5e8e..dfa1d6b 100644 --- gcc/testsuite/g++.dg/cpp0x/constexpr-neg1.C +++ gcc/testsuite/g++.dg/cpp0x/constexpr-neg1.C @@ -29,7 +29,7 @@ int next(constexpr int x) { // { dg-error "parameter" } extern constexpr int memsz; // { dg-error "definition" } // error: return type is void -constexpr void f(int x) // { dg-error "void" } +constexpr void f(int x) // { dg-error "void" "" { target c++11_only } } { /* ... */ } // error: use of decrement constexpr int prev(int x) diff --git gcc/testsuite/g++.dg/cpp1y/constexpr-void1.C gcc/testsuite/g++.dg/cpp1y/constexpr-void1.C index e69de29..10ef5bc 100644 --- gcc/testsuite/g++.dg/cpp1y/constexpr-void1.C +++ gcc/testsuite/g++.dg/cpp1y/constexpr-void1.C @@ -0,0 +1,13 @@ +// { dg-do compile { target c++14 } } + +struct S +{ + int i = 20; + + constexpr void + foo (void) + { + if (i > 20) + __builtin_abort (); + } +}; Marek