ctutils: remove target_pointer_width gating (#1389)

From #1387, via rustc itself:

    expected values for `target_pointer_width` are: `16`, `32`, and `64`

So these impls should actually be ubiquitously available, for now.

If we remove the gating in this crate, then all we need to do to handle
new pointer widths is ship a fix for `cmov`.

Author: tarcieri

ctutils/src/traits/ct_lookup.rs

@@ -99,8 +99,6 @@ mod tests {
             assert!(EXAMPLE.ct_lookup(4u32).is_none().to_bool());
         }
 
-        // usize only has a `CtEq` impl on 32-bit and 64-bit targets currently
-        #[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
         #[test]
         fn ct_lookup_usize() {
             assert_eq!(EXAMPLE.ct_lookup(0usize).unwrap(), 1);
@@ -125,8 +123,6 @@ mod tests {
             assert!(EXAMPLE.ct_lookup(4u32).is_none().to_bool());
         }
 
-        // usize only has a `CtEq` impl on 32-bit and 64-bit targets currently
-        #[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
         #[test]
         fn ct_lookup_usize() {
             assert_eq!(EXAMPLE.ct_lookup(0usize).unwrap(), 1);

ctutils/src/traits/ct_select.rs

@@ -101,7 +101,9 @@ macro_rules! impl_ct_select_with_ct_assign {
     };
 }
 
-impl_ct_select_with_ct_assign!(i8, i16, i32, i64, i128, u8, u16, u32, u64, u128);
+impl_ct_select_with_ct_assign!(
+    i8, i16, i32, i64, i128, isize, u8, u16, u32, u64, u128, usize
+);
 
 /// Impl `CtSelect` for `NonZero<T>` by calling the `CtSelect` impl for `T`.
 macro_rules! impl_ct_select_for_nonzero_integer {
@@ -135,38 +137,6 @@ impl_ct_select_for_nonzero_integer!(
     NonZeroU128
 );
 
-#[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
-impl CtSelect for isize {
-    #[cfg(target_pointer_width = "32")]
-    #[inline]
-    fn ct_select(&self, other: &Self, choice: Choice) -> Self {
-        (*self as i32).ct_select(&(*other as i32), choice) as isize
-    }
-
-    #[cfg(target_pointer_width = "64")]
-    #[allow(clippy::cast_possible_truncation)]
-    #[inline]
-    fn ct_select(&self, other: &Self, choice: Choice) -> Self {
-        (*self as i64).ct_select(&(*other as i64), choice) as isize
-    }
-}
-
-#[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
-impl CtSelect for usize {
-    #[cfg(target_pointer_width = "32")]
-    #[inline]
-    fn ct_select(&self, other: &Self, choice: Choice) -> Self {
-        (*self as u32).ct_select(&(*other as u32), choice) as usize
-    }
-
-    #[cfg(target_pointer_width = "64")]
-    #[allow(clippy::cast_possible_truncation)]
-    #[inline]
-    fn ct_select(&self, other: &Self, choice: Choice) -> Self {
-        (*self as u64).ct_select(&(*other as u64), choice) as usize
-    }
-}
-
 impl CtSelect for cmp::Ordering {
     fn ct_select(&self, other: &Self, choice: Choice) -> Self {
         // `Ordering` is `#[repr(i8)]` where: