refactor + reword

Author: LorrensP-2158466

src/tools/miri/src/intrinsics/mod.rs

@@ -517,8 +517,8 @@ fn random_nan<S: Semantics>(rng: &mut StdRng) -> IeeeFloat<S> {
 ///
 /// For `powf*` operations of the form:
 ///
-/// - `x^(±0)` where `x` is a SNaN
-/// - `1^y` where `y` is SNaN
+/// - `(SNaN)^(±0)`
+/// - `1^(SNaN)`
 ///
 /// The result is implementation-defined:
 /// - musl returns for both `1.0`
@@ -553,13 +553,9 @@ fn fixed_float_value<S: Semantics>(
 
         // x^(±0) = 1 for any x, even a NaN, *but* not a SNaN
         ("powf32" | "powf64", [base, exp]) if exp.is_zero() => {
+            let rng = ecx.machine.rng.get_mut();
             // Handle both the musl and glibc cases non-deterministically.
-            if base.is_signaling() {
-                let rng = ecx.machine.rng.get_mut();
-                if rng.random() { one } else { random_nan(rng) }
-            } else {
-                one
-            }
+            if !base.is_signaling() || rng.random() { one } else { random_nan(rng) }
         }
 
         // There are a lot of cases for fixed outputs according to the C Standard, but these are mainly INF or zero
@@ -570,7 +566,7 @@ fn fixed_float_value<S: Semantics>(
 
 /// Returns `Some(output)` if `powi` (called `pown` in C) results in a fixed value specified in the C standard
 /// (specifically, C23 annex F.10.4.6) when doing `base^exp`. Otherwise, returns `None`.
-// REVIEW: I'm not sure what I should document here about pown(1, SNaN) since musl and glibc do the same and the C standard is explicit here.
+// TODO: I'm not sure what I should document here about pown(1, SNaN) since musl and glibc do the same and the C standard is explicit here.
 fn fixed_powi_float_value<S: Semantics>(
     ecx: &mut MiriInterpCx<'_>,
     base: IeeeFloat<S>,

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

@@ -1071,18 +1071,18 @@ pub fn libm() {
         ($pow_op:expr) => {{
             let mut nan_seen = false;
             let mut one_seen = false;
-        
+
             for _ in 0..64 {
                 let res = $pow_op;
                 nan_seen |= res.is_nan();
                 one_seen |= res == 1.0;
 
-                // speedup test
+                // little speedup
                 if nan_seen && one_seen { break; };
             }
 
             let op_as_str = stringify!($pow_op);
-        
+
             assert!(nan_seen && one_seen, "{} should return both `NaN` or `1.0` randomly", op_as_str);
         }};
     }