libstdc++: Fix atomic<long double> tests (PR 91153, PR 93224)

These tests fail with AIX double double. Use different floating point
values that behave less surprisingly.

libstdc++-v3/ChangeLog:

	PR libstdc++/91153
	PR target/93224
	* testsuite/29_atomics/atomic_float/1.cc: Use different values
	for tests.
	* testsuite/29_atomics/atomic_ref/float.cc: Likewise.

(cherry picked from commit c6f431bba531bac3212b66069cf0f9718edf0132)

libstdc++-v3/testsuite/29_atomics/atomic_float/1.cc

@@ -453,27 +453,28 @@ test03()
     ok = a1.compare_exchange_strong(expected, 3.2l, mo);
     VERIFY( !ok && a1.load() == 2.56l && expected == 2.56l );
 
-    f0 = a0.fetch_add(1.2l);
-    VERIFY( f0 == 12.8l );
-    VERIFY( a0 == 14.0l );
-    f1 = a1.fetch_add(2.4l, mo);
-    VERIFY( f1 == 2.56l );
-    VERIFY( a1 == 4.96l );
-
-    f0 = a0.fetch_sub(1.2l);
-    VERIFY( f0 == 14.0l );
-    VERIFY( a0 == 12.8l );
-    f1 = a1.fetch_sub(3.5l, mo);
-    VERIFY( f1 == 4.96l );
-    VERIFY( a1 == 1.46l );
-
-    f0 = a0 += 1.2l;
-    VERIFY( f0 == 14.0l );
-    VERIFY( a0 == 14.0l );
-
-    f0 = a0 -= 0.8l;
-    VERIFY( f0 == 13.2l );
-    VERIFY( a0 == 13.2l );
+    a1 = a0 = 0.5l;
+    f0 = a0.fetch_add(0.25l);
+    VERIFY( f0 == 0.5l );
+    VERIFY( a0 == 0.75l );
+    f1 = a1.fetch_add(0.25l, mo);
+    VERIFY( f1 == 0.5l );
+    VERIFY( a1 == 0.75l );
+
+    f0 = a0.fetch_sub(0.5l);
+    VERIFY( f0 == 0.75l );
+    VERIFY( a0 == 0.25l );
+    f1 = a1.fetch_sub(0.5l, mo);
+    VERIFY( f1 == 0.75l );
+    VERIFY( a1 == 0.25l );
+
+    f0 = a0 += 0.75l;
+    VERIFY( f0 == 1.0l );
+    VERIFY( a0 == 1.0l );
+
+    f0 = a0 -= 0.5l;
+    VERIFY( f0 == 0.5l );
+    VERIFY( a0 == 0.5l );
   }
 
   // Repeat for volatile std::atomic<long double>
@@ -540,27 +541,28 @@ test03()
     ok = a1.compare_exchange_strong(expected, 3.2l, mo);
     VERIFY( !ok && a1.load() == 2.56l && expected == 2.56l );
 
-    f0 = a0.fetch_add(1.2l);
-    VERIFY( f0 == 12.8l );
-    VERIFY( a0 == 14.0l );
-    f1 = a1.fetch_add(2.4l, mo);
-    VERIFY( f1 == 2.56l );
-    VERIFY( a1 == 4.96l );
-
-    f0 = a0.fetch_sub(1.2l);
-    VERIFY( f0 == 14.0l );
-    VERIFY( a0 == 12.8l );
-    f1 = a1.fetch_sub(3.5l, mo);
-    VERIFY( f1 == 4.96l );
-    VERIFY( a1 == 1.46l );
-
-    f0 = a0 += 1.2l;
-    VERIFY( f0 == 14.0l );
-    VERIFY( a0 == 14.0l );
-
-    f0 = a0 -= 0.8l;
-    VERIFY( f0 == 13.2l );
-    VERIFY( a0 == 13.2l );
+    a1 = a0 = 0.5l;
+    f0 = a0.fetch_add(0.25l);
+    VERIFY( f0 == 0.5l );
+    VERIFY( a0 == 0.75l );
+    f1 = a1.fetch_add(0.25l, mo);
+    VERIFY( f1 == 0.5l );
+    VERIFY( a1 == 0.75l );
+
+    f0 = a0.fetch_sub(0.5l);
+    VERIFY( f0 == 0.75l );
+    VERIFY( a0 == 0.25l );
+    f1 = a1.fetch_sub(0.5l, mo);
+    VERIFY( f1 == 0.75l );
+    VERIFY( a1 == 0.25l );
+
+    f0 = a0 += 0.75l;
+    VERIFY( f0 == 1.0l );
+    VERIFY( a0 == 1.0l );
+
+    f0 = a0 -= 0.5l;
+    VERIFY( f0 == 0.5l );
+    VERIFY( a0 == 0.5l );
   }
 }
 

libstdc++-v3/testsuite/29_atomics/atomic_ref/float.cc

@@ -267,31 +267,32 @@ test03()
     ok = a.compare_exchange_strong(expected, 6.4l, mo);
     VERIFY( !ok && a.load() == 204.8l && expected == 204.8l );
 
-    v = a.fetch_add(3.2l);
-    VERIFY( v == 204.8l );
-    VERIFY( a == 208.0l );
-    v = a.fetch_add(-8.5l, mo);
-    VERIFY( v == 208.0l );
-    VERIFY( a == 199.5l );
-
-    v = a.fetch_sub(109.5l);
-    VERIFY( v == 199.5l );
-    VERIFY( a == 90.0l );
-    v = a.fetch_sub(2, mo);
-    VERIFY( v == 90.0l );
-    VERIFY( a == 88.0l );
-
-    v = a += 5.0l;
-    VERIFY( v == 93.0l );
-    VERIFY( a == 93.0l );
-
-    v = a -= 6.5l;
-    VERIFY( v == 86.5l );
-    VERIFY( a == 86.5l );
+    a = 0.5l;
+    v = a.fetch_add(0.5l);
+    VERIFY( v == 0.5l );
+    VERIFY( a == 1.0l );
+    v = a.fetch_add(-0.2l, mo);
+    VERIFY( v == 1.0l );
+    VERIFY( a == 0.8l );
+
+    v = a.fetch_sub(0.4l);
+    VERIFY( v == 0.8l );
+    VERIFY( a == 0.4l );
+    v = a.fetch_sub(-0.4l, mo);
+    VERIFY( v == 0.4l );
+    VERIFY( a == 0.8l );
+
+    v = a += .8l;
+    VERIFY( v == 1.6l );
+    VERIFY( a == 1.6l );
+
+    v = a -= 0.6l;
+    VERIFY( v == 1.0l );
+    VERIFY( a == 1.0l );
   }
 
   if constexpr (std::atomic_ref<long double>::is_always_lock_free)
-    VERIFY( value == 86.5l );
+    VERIFY( value == 1.0l );
 }
 
 void