core: Move intrinsic float functionality from std

The Float trait in libstd is quite a large trait which has dependencies on cmath
(libm) and such, which libcore cannot satisfy. It also has many functions that
libcore can implement, however, as LLVM has intrinsics or they're just bit
twiddling.

This commit moves what it can of the Float trait from the standard library into
libcore to allow floats to be usable in the core library. The remaining
functions are now resident in a FloatMath trait in the standard library (in the
prelude now). Previous code which was generic over just the Float trait may now
need to be generic over the FloatMath trait.

[breaking-change]

1 files changed, 3 insertions, 3 deletions

diff --git a/src/libtest/stats.rs b/src/libtest/stats.rs
index bf40a2d601f..b3c768a5199 100644
--- a/src/libtest/stats.rs
+++ b/src/libtest/stats.rs
@@ -38,7 +38,7 @@ fn local_sort<T: Float>(v: &mut [T]) {
 }
 
 /// Trait that provides simple descriptive statistics on a univariate set of numeric samples.
-pub trait Stats <T: Float + FromPrimitive>{
+pub trait Stats <T: FloatMath + FromPrimitive>{
 
     /// Sum of the samples.
     ///
@@ -143,7 +143,7 @@ pub struct Summary<T> {
     pub iqr: T,
 }
 
-impl<T: Float + FromPrimitive> Summary<T> {
+impl<T: FloatMath + FromPrimitive> Summary<T> {
 
     /// Construct a new summary of a sample set.
     pub fn new(samples: &[T]) -> Summary<T> {
@@ -164,7 +164,7 @@ impl<T: Float + FromPrimitive> Summary<T> {
     }
 }
 
-impl<'a,T: Float + FromPrimitive> Stats<T> for &'a [T] {
+impl<'a,T: FloatMath + FromPrimitive> Stats<T> for &'a [T] {
 
     // FIXME #11059 handle NaN, inf and overflow
     #[allow(deprecated_owned_vector)]