Re: [PATCH] c++/modules testsuite: avoid expensive ggc-min-expand=0

[Jason Merrill <jason@redhat.com>]

On 4/24/24 05:49, Patrick Palka wrote:
> On Tue, 23 Apr 2024, Jason Merrill wrote:
> 
>> On 4/23/24 11:28, Patrick Palka wrote:
>>> Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
>>
>> Is the test being run for multiple standard levels?  I'd rather restrict it to
>> one and keep fully testing GC-safety.
> 
> Ah yeah, looks like it runs three times by default, in C++17, C++20 and
> C++23 mode.  Like so?  The speedup is almost as good as using
> ggc-min-expand=1.

OK.

> Interestingly, restricting to one standard level _and_ using
> ggc-min-expand=1 does not give further speedup.
> 
> -- >8 --
> 
> Subject: [PATCH] c++/modules testsuite: restrict expensive pr99023 test
> 
> The pr99023 testcase uses --param=ggc-min-expand=0 which forces a GC
> during every collection point and consequently is very slow to run,
> and ends up being the main bottleneck of the modules.exp testsuite.
> 
> So this patch restricts this test to run once, in C++20 mode, instead of
> multiple times (C++17, C++20 and C++23 mode by default).  After this
> patch the modules.exp testsuite finishes in 3m instead of 3m40s with -j8
> on my machine.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/modules/pr99023_a.X: Run only in C++20 mode.
> 	* g++.dg/modules/pr99023_b.X: Likewise.
> ---
>   gcc/testsuite/g++.dg/modules/pr99023_a.X | 1 +
>   gcc/testsuite/g++.dg/modules/pr99023_b.X | 1 +
>   2 files changed, 2 insertions(+)
> 
> diff --git a/gcc/testsuite/g++.dg/modules/pr99023_a.X b/gcc/testsuite/g++.dg/modules/pr99023_a.X
> index c872d15f792..507e9569535 100644
> --- a/gcc/testsuite/g++.dg/modules/pr99023_a.X
> +++ b/gcc/testsuite/g++.dg/modules/pr99023_a.X
> @@ -1,4 +1,5 @@
>   // PR c++/99023, ICE
> +// { dg-require-effective-target c++20_only }
>   // { dg-additional-options {-x c++-system-header initializer_list -fmodules-ts --param ggc-min-expand=0} }
>   
>   // { dg-prune-output {linker input file unused} }
> diff --git a/gcc/testsuite/g++.dg/modules/pr99023_b.X b/gcc/testsuite/g++.dg/modules/pr99023_b.X
> index ca5f32e5bcc..59d32bee8d5 100644
> --- a/gcc/testsuite/g++.dg/modules/pr99023_b.X
> +++ b/gcc/testsuite/g++.dg/modules/pr99023_b.X
> @@ -1,4 +1,5 @@
>   // PR c++/99023, ICE
> +// { dg-require-effective-target c++20_only }
>   // { dg-additional-options {-x c++-system-header iostream -fmodules-ts -flang-info-include-translate=<initializer_list> --param ggc-min-expand=0} }
>   
>   // { dg-prune-output {linker input file unused} }