On Wed, Feb 5, 2020 at 4:18 PM Marek Polacek <pola...@redhat.com> wrote:
> Since reshape_init_array_1 can now reuse a single constructor for
> an array of non-aggregate type, we might run into a scenario where
> we reuse a constructor with TREE_SIDE_EFFECTS. This broke this test
> because we have something like { { expr } } and we try to reshape it,
> so we recurse on the inner CONSTRUCTOR, reuse an existing CONSTRUCTOR
> with TREE_SIDE_EFFECTS, and then ICE on the discrepancy because the
> outermost CONSTRUCTOR doesn't have TREE_SIDE_EFFECTS. In this case
> EXPR was a call to an operator function so TREE_SIDE_EFFECTS should
> be set. Naturally one would want to fix this by calling
> recompute_constructor_flags in an appropriate place so that the flags
> on the CONSTRUCTORs match. The appropriate place would be at the end
> of reshape_init, but this breaks initlist109.C: there we are dealing
> with { { TARGET_EXPR <{}> } } where the outermost { } is TREE_CONSTANT
> but the inner { } is not, so recompute_constructor_flags would clear
> the constant flag in the outermost { }. Seems resonable but it upsets
> check_initializer which then complains about "non-constant in-class
> initialization invalid for static member". TARGET_EXPRs are always
> created with TREE_SIDE_EFFECTS on, but that is mutually exclusive
> with TREE_CONSTANT. So we're in a bind.
>
> Fixed by not reusing a CONSTRUCTOR that has TREE_SIDE_EFFECTS; in the
> grand scheme of things it isn't measurable: it only affects ~3 tests
> in the testsuite.
>
Bootstrapped/regtested on x86_64-linux, ok for trunk?
>
OK.
PR c++/93559 - ICE with CONSTRUCTOR flags verification.
> * decl.c (reshape_init_array_1): Don't reuse a CONSTRUCTOR with
> TREE_SIDE_EFFECTS.
>
> * g++.dg/cpp0x/initlist119.C: New test.
> * g++.dg/cpp0x/initlist120.C: New test.
> ---
> gcc/cp/decl.c | 4 +++-
> gcc/testsuite/g++.dg/cpp0x/initlist119.C | 15 +++++++++++++++
> gcc/testsuite/g++.dg/cpp0x/initlist120.C | 16 ++++++++++++++++
> 3 files changed, 34 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist119.C
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist120.C
>
> diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
> index 859fd1bb931..d90007ba475 100644
> --- a/gcc/cp/decl.c
> +++ b/gcc/cp/decl.c
> @@ -5989,7 +5989,9 @@ reshape_init_array_1 (tree elt_type, tree max_index,
> reshape_iter *d,
> /* The initializer for an array is always a CONSTRUCTOR. If this is the
> outermost CONSTRUCTOR and the element type is non-aggregate, we
> don't need
> to build a new one. */
> - bool reuse = first_initializer_p && !CP_AGGREGATE_TYPE_P (elt_type);
> + bool reuse = (first_initializer_p
> + && !CP_AGGREGATE_TYPE_P (elt_type)
> + && !TREE_SIDE_EFFECTS (first_initializer_p));
> if (reuse)
> new_init = first_initializer_p;
> else
> diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist119.C
> b/gcc/testsuite/g++.dg/cpp0x/initlist119.C
> new file mode 100644
> index 00000000000..80f391f64c7
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/initlist119.C
> @@ -0,0 +1,15 @@
> +// PR c++/93559 - ICE with CONSTRUCTOR flags verification.
> +// { dg-do compile { target c++11 } }
> +
> +struct E { int d[10]; };
> +
> +struct S {
> + constexpr int operator()(char) { return 42; }
> +};
> +
> +template <typename> struct X {
> + constexpr static E foo(S s) { return {{s(1)}}; }
> +};
> +
> +S s;
> +static_assert((X<S>::foo(s), 1), "");
> diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist120.C
> b/gcc/testsuite/g++.dg/cpp0x/initlist120.C
> new file mode 100644
> index 00000000000..8d03166e197
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/initlist120.C
> @@ -0,0 +1,16 @@
> +// PR c++/93559 - ICE with CONSTRUCTOR flags verification.
> +// { dg-do compile { target c++11 } }
> +
> +struct F { int d[10]; };
> +struct E { F f; };
> +
> +struct S {
> + constexpr int operator()(char) { return 42; }
> +};
> +
> +template <typename> struct X {
> + constexpr static E foo(S s) { return {{{s(1)}}}; }
> +};
> +
> +S s;
> +static_assert((X<S>::foo(s), 1), "");
>
> base-commit: 91bc3c98851670360dfcd312399c3ba35fb50231
> --
> Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA
>
>
