Index: libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.float.pass.cpp
===================================================================
--- libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.float.pass.cpp
+++ libcxx/test/std/numerics/numeric.ops/numeric.ops.midpoint/midpoint.float.pass.cpp
@@ -81,25 +81,34 @@
     assert(d0 < d1);  // sanity checking
     assert(d1 < d2);  // sanity checking
 
-//  Since there's nothing in between, the midpoint has to be one or the other
-    T res;
-    res = std::midpoint(d0, d1);
-    assert(res == d0 || res == d1);
-    assert(d0 <= res);
-    assert(res <= d1);
-    res = std::midpoint(d1, d0);
-    assert(res == d0 || res == d1);
-    assert(d0 <= res);
-    assert(res <= d1);
-
-    res = std::midpoint(d1, d2);
-    assert(res == d1 || res == d2);
-    assert(d1 <= res);
-    assert(res <= d2);
-    res = std::midpoint(d2, d1);
-    assert(res == d1 || res == d2);
-    assert(d1 <= res);
-    assert(res <= d2);
+#if defined(__PPC__) && __LONG_DOUBLE_128__ && !__LONG_DOUBLE_IEEE128__
+    // For 128 bit long double implemented as 2 doubles on PowerPC,
+    // nextafterl() of libm gives imprecise results which fails the
+    // midpoint() tests below. So skip the test for this case.
+    if constexpr (sizeof(T) != 16)
+#endif
+    {
+        // Since there's nothing in between, the midpoint has to be one or
+        // the other.
+        T res;
+        res = std::midpoint(d0, d1);
+        assert(res == d0 || res == d1);
+        assert(d0 <= res);
+        assert(res <= d1);
+        res = std::midpoint(d1, d0);
+        assert(res == d0 || res == d1);
+        assert(d0 <= res);
+        assert(res <= d1);
+
+        res = std::midpoint(d1, d2);
+        assert(res == d1 || res == d2);
+        assert(d1 <= res);
+        assert(res <= d2);
+        res = std::midpoint(d2, d1);
+        assert(res == d1 || res == d2);
+        assert(d1 <= res);
+        assert(res <= d2);
+    }
 }