[gcc r11-2408] testsuite: libstdc++ atomic_float/value_init.cc requires libatomic

[David Edelsohn <dje@gcc.gnu.org>]

https://gcc.gnu.org/g:55ede0bb87e74463c5b89fbfd501e85e9e683048

commit r11-2408-g55ede0bb87e74463c5b89fbfd501e85e9e683048
Author: David Edelsohn <dje.gcc@gmail.com>
Date:   Tue Jul 28 16:22:04 2020 -0400

    testsuite: libstdc++ atomic_float/value_init.cc requires libatomic
    
    atomic_float/value_init.cc requires libatomic for some targets, i.e., when
    it tries to perform an atomic operation with a 64 bit floating point
    double type on a 32 bit target.  This patch adds AIX and Darwin to the
    list of targets that require the libatomic option and adds the option to
    the atomic_float/value_init.cc testcase.
    
    libstdc++-v3/ChangeLog:
    
    2020-07-28  David Edelsohn  <dje.gcc@gmail.com>
                Jonathan Wakely  <jwakely@redhat.com>
                Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
    
            * testsuite/lib/dg-options.exp (add_options_for_libatomic): Add
            target powerpc-ibm-aix* and powerpc*-*-darwin*.
            * testsuite/29_atomics/atomic_float/value_init.cc: Add options
            for libatomic.

Diff:
---
 libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc | 1 +
 libstdc++-v3/testsuite/lib/dg-options.exp                    | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc b/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc
index 237c0dd13ed..38af9bdc8d4 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_float/value_init.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-add-options libatomic }
 
 #include <atomic>
 #include <testsuite_hooks.h>
diff --git a/libstdc++-v3/testsuite/lib/dg-options.exp b/libstdc++-v3/testsuite/lib/dg-options.exp
index 9bfae71adf3..d3f61cb5267 100644
--- a/libstdc++-v3/testsuite/lib/dg-options.exp
+++ b/libstdc++-v3/testsuite/lib/dg-options.exp
@@ -260,7 +260,10 @@ proc add_options_for_net_ts { flags } {
 # Add to FLAGS all the target-specific flags to link to libatomic, if required.
 
 proc add_options_for_libatomic { flags } {
-    if { [istarget hppa*-*-hpux*] || [istarget riscv*-*-*] } {
+    if { [istarget hppa*-*-hpux*]
+	 || [istarget powerpc-ibm-aix*]
+	 || [istarget powerpc*-*-darwin*]
+	 || [istarget riscv*-*-*] } {
 	return "$flags -L../../libatomic/.libs -latomic"
     }
     return $flags