> Date: Wed, 7 Feb 2024 21:11:59 -0500
> From: Marek Polacek <pola...@redhat.com>
> On Wed, Feb 07, 2024 at 04:32:57PM -0500, Jason Merrill wrote:
> > On 2/6/24 19:23, Hans-Peter Nilsson wrote:
> > > > Date: Mon, 22 Jan 2024 14:33:59 -0500
> > > > From: Marek Polacek <pola...@redhat.com>
> > >
> > > > On Mon, Jan 22, 2024 at 06:02:32PM +0100, Hans-Peter Nilsson wrote:
> > > > > I don't really know whether this is the right way to treat
> > > > > CONVERT_EXPR as below, but... Regtested native
> > > > > x86_64-linux-gnu. Ok to commit?
> > > >
> > > > Thanks for taking a look at this problem.
> > >
> > > Thanks for the initial review.
> > Incidentally, these testcases seem to require C++14; you can't have a switch
> > in a constexpr function in C++11.
> >
> > Jason
>
> > diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
> > index 2ebb1470dd5..fa346fe01c9 100644
> > --- a/gcc/cp/constexpr.cc
> > +++ b/gcc/cp/constexpr.cc
> > @@ -7106,6 +7106,16 @@ cxx_eval_switch_expr (const constexpr_ctx *ctx, tree
> > t,
> > cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue,
> > non_constant_p, overflow_p);
> > VERIFY_CONSTANT (cond);
> > + if (TREE_CODE (cond) != INTEGER_CST)
> > + {
> > + /* If the condition doesn't reduce to an INTEGER_CST it isn't a
> > usable
> > + switch condition even if it's constant enough for other things
> > + (c++/113545). */
> > + gcc_checking_assert (ctx->quiet);
> > + *non_constant_p = true;
> > + return t;
> > + }
> > +
> > *jump_target = cond;
> >
> > tree body
>
> The patch makes sense to me, although I'm afraid that losing the
> REINTERPRET_CAST_P flag will cause other issues.
>
> HP, sorry that I never got back to you. I would be more than happy to
> take the patch above, add some tests and test/bootstrap it, unless you
> want to do that yourself.
>
> Thanks & sorry again,
No worries, feel very welcome to deal with handling the
actual fix. Also, you're better prepared than me, when it
comes to dealing with any possible fallout. :)
I'll send an updated version of the test-cases, moving them
to the C++14 test directory (cpp1y, right?) and qualify them
as c++14 instead, as Jason pointed out.
brgds, H-P
