Ping for the xfailed testsuite patch below the review
(actual constexpr.cc patch to be handled separately):
> From: Hans-Peter Nilsson <h...@axis.com>
> Date: Tue, 23 Jan 2024 05:55:00 +0100
>
> > Date: Mon, 22 Jan 2024 14:33:59 -0500
> > From: Marek Polacek <pola...@redhat.com>
>
> > The problem seems to be more about conversion so
> > g++.dg/conversion/reinterpret5.C
> > or g++.dg/cpp0x/constexpr-reinterpret3.C seems more appropriate.
> >
> > > @@ -0,0 +1,49 @@
> >
> > Please add
> >
> > PR c++/113545
>
> > > + unsigned const char c =
> > > swbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo));
> > > + xyzzy(c);
> > > + unsigned const char d =
> > > ifbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo));
> >
> > I suppose we should also test a C-style cast (which leads to a
> > reinterpret_cast
> > in this case).
> >
> > Maybe check we get an error when c/d are constexpr (that used to ICE).
>
> Like this? Not sure about the value of that variant, but here goes.
>
> I checked that these behave as expected (xfail as ICE properly) without the
> previosly posted patch to cp/constexpr.cc and XPASS with it applied.
>
> Ok to commit?
>
> -- >8 --
> Subject: [PATCH] c++: testcases for PR113545 (constexpr with switch and
> passing non-constexpr parameter)
>
> gcc/testsuite:
> PR c++/113545
> * g++.dg/cpp0x/constexpr-reinterpret3.C,
> g++.dg/cpp0x/constexpr-reinterpret4.C: New tests.
> ---
> .../g++.dg/cpp0x/constexpr-reinterpret3.C | 55 +++++++++++++++++++
> .../g++.dg/cpp0x/constexpr-reinterpret4.C | 54 ++++++++++++++++++
> 2 files changed, 109 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret3.C
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret4.C
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret3.C
> b/gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret3.C
> new file mode 100644
> index 000000000000..319cc5e8bee9
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret3.C
> @@ -0,0 +1,55 @@
> +// PR c++/113545
> +// { dg-do run { target c++11 } }
> +// { dg-ice "PR112545 - constexpr function with switch called for
> reinterpret_cast" }
> +
> +char foo;
> +
> +// This one caught a call to gcc_unreachable in
> +// cp/constexpr.cc:label_matches, when passed a convert_expr from the
> +// cast in the call.
> +constexpr unsigned char swbar(__UINTPTR_TYPE__ baz)
> +{
> + switch (baz)
> + {
> + case 13:
> + return 11;
> + case 14:
> + return 78;
> + case 2048:
> + return 13;
> + default:
> + return 42;
> + }
> +}
> +
> +// For reference, the equivalent* if-statements.
> +constexpr unsigned char ifbar(__UINTPTR_TYPE__ baz)
> +{
> + if (baz == 13)
> + return 11;
> + else if (baz == 14)
> + return 78;
> + else if (baz == 2048)
> + return 13;
> + else
> + return 42;
> +}
> +
> +__attribute__ ((__noipa__))
> +void xyzzy(int x)
> +{
> + if (x != 42)
> + __builtin_abort ();
> +}
> +
> +int main()
> +{
> + unsigned const char c = swbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo));
> + xyzzy(c);
> + unsigned const char d = ifbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo));
> + xyzzy(d);
> + unsigned const char e = swbar((__UINTPTR_TYPE__) &foo);
> + xyzzy(e);
> + unsigned const char f = ifbar((__UINTPTR_TYPE__) &foo);
> + xyzzy(f);
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret4.C
> b/gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret4.C
> new file mode 100644
> index 000000000000..4d0fdf2c0a78
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-reinterpret4.C
> @@ -0,0 +1,54 @@
> +// PR c++/113545
> +// { dg-do compile { target c++11 } }
> +
> +char foo;
> +
> +// This one caught a call to gcc_unreachable in
> +// cp/constexpr.cc:label_matches, when passed a convert_expr from the
> +// cast in the call.
> +constexpr unsigned char swbar(__UINTPTR_TYPE__ baz)
> +{
> + switch (baz)
> + {
> + case 13:
> + return 11;
> + case 14:
> + return 78;
> + case 2048:
> + return 13;
> + default:
> + return 42;
> + }
> +}
> +
> +// For reference, the equivalent* if-statements.
> +constexpr unsigned char ifbar(__UINTPTR_TYPE__ baz)
> +{
> + if (baz == 13)
> + return 11;
> + else if (baz == 14)
> + return 78;
> + else if (baz == 2048)
> + return 13;
> + else
> + return 42;
> +}
> +
> +__attribute__ ((__noipa__))
> +void xyzzy(int x)
> +{
> + if (x != 42)
> + __builtin_abort ();
> +}
> +
> +int main()
> +{
> + unsigned constexpr char c =
> swbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo)); // { dg-error "conversion
> from pointer type" }
> + xyzzy(c);
> + unsigned constexpr char d =
> ifbar(reinterpret_cast<__UINTPTR_TYPE__>(&foo)); // { dg-error "conversion
> from pointer type" }
> + xyzzy(d);
> + unsigned constexpr char e = swbar((__UINTPTR_TYPE__) &foo); // { dg-error
> "conversion from pointer type" }
> + xyzzy(e);
> + unsigned constexpr char f = ifbar((__UINTPTR_TYPE__) &foo); // { dg-error
> "conversion from pointer type" }
> + xyzzy(f);
> +}
> --
> 2.30.2
>
