add fixme regarding powi(snan, 0)

Author: LorrensP-2158466

src/tools/miri/tests/pass/float.rs

@@ -1046,9 +1046,6 @@ pub fn libm() {
 
     // For pow (powf in rust) the C standard says:
     // x^0 = 1 for all x even a sNaN
-    // FIXME: But the ecosystem is inconistent with this, in the future we should return either
-    // 1 or the NaN. Add correct tests when we actually do this.
-    // Currently we return 1.
     assert_eq!(SINGLE_SNAN.powf(0.0), 1.0);
     assert_eq!(DOUBLE_SNAN.powf(0.0), 1.0);
     // f*::NAN is a quiet NAN and should return 1 as well.
@@ -1062,8 +1059,11 @@ pub fn libm() {
 
     // For pown (powi in rust) the C standard says:
     // x^0 = 1 for all x not a sNaN.
-    assert_ne!(SINGLE_SNAN.powi(0), 1.0);
-    assert_ne!(DOUBLE_SNAN.powi(0), 1.0);
+    // FIXME: But the ecosystem is inconistent with this, in the future we should return either
+    // 1 or the NaN. Add correct tests when we actually do this.
+    //     Should we follow glibc and libm or the C Standard itself?
+    // assert_ne!(SINGLE_SNAN.powi(0), 1.0);
+    // assert_ne!(DOUBLE_SNAN.powi(0), 1.0);
     // f*::NAN is a quiet NAN and should return 1 as well.
     assert_eq!(f32::NAN.powi(0), 1.0);
     assert_eq!(f64::NAN.powi(0), 1.0);