[gcc r14-10111] c++/modules testsuite: restrict expensive pr99023 test

[Patrick Palka <ppalka@gcc.gnu.org>]

https://gcc.gnu.org/g:26a3edbe2357cf975f345ad1b59b9f9a3444316e

commit r14-10111-g26a3edbe2357cf975f345ad1b59b9f9a3444316e
Author: Patrick Palka <ppalka@redhat.com>
Date:   Wed Apr 24 17:51:54 2024 -0400

    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.
    
    Reviewed-by: Jason Merrill <jason@redhat.com>

Diff:
---
 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} }