On Wed, Dec 13, 2023 at 08:51:16AM +0100, Richard Biener wrote:
> On Tue, 12 Dec 2023, Peter Bergner wrote:
>
> > On 12/12/23 8:36 PM, Jason Merrill wrote:
> > > This test is failing for me below C++17, I think you need
> > >
> > > // { dg-do compile { target c++17 } }
> > > or
> > > // { dg-require-effective-target c++17 }
> >
> > Sorry about that. Should we do the above or should we just add
> > -std=c++17 to dg-options? ...or do we need to do both?
>
> Just do the above, the C++ testsuite iterates over all standards,
> adding -std=c++17 would just run that 5 times. But the above
> properly skips unsupported cases.
I believe if one uses explicit -std=gnu++17 or -std=c++17 in dg-options
then it will not iterate:
# If the testcase specifies a standard, use that one.
# If not, run it under several standards, allowing GNU extensions
# if there's a dg-options line.
if ![search_for $test "-std=*++"] {
and otherwise how many times exactly it iterates depends on what the user
asked for or what effective target is there (normally the default is
to iterate 4 times (98,14,17,20), one can use e.g.
GXX_TESTSUITE_STDS=98,11,14,17,20,23,26 to iterate 7 times, or the
default also changes if c++23, c++26 or c++11_only effective targets
are present somewhere in the test.
But sure, if the test is valid in C++17, 20, 23, 26, then
// { dg-do compile { target c++17 } }
is best (unless the test is mostly language version independent and
very expensive to compile or run).
Jakub
