Remove dependencies on libm functions from libcore.

There wasn't any particular reason the functions needed to be there
anyway, so just get rid of them, and adjust libstd to compensate.

With this change, libcore depends on exactly two floating-point functions:
fmod and fmodf.  They are implicitly referenced because they are
used to implement "%".

1 files changed, 16 insertions, 2 deletions

diff --git a/src/libcoretest/num/flt2dec/mod.rs b/src/libcoretest/num/flt2dec/mod.rs
index 488cd3a779c..8ae33a44202 100644
--- a/src/libcoretest/num/flt2dec/mod.rs
+++ b/src/libcoretest/num/flt2dec/mod.rs
@@ -164,12 +164,26 @@ fn check_exact<F, T>(mut f: F, v: T, vstr: &str, expected: &[u8], expectedk: i16
     }
 }
 
+trait TestableFloat : DecodableFloat + fmt::Display {
+    /// Returns `x * 2^exp`. Almost same to `std::{f32,f64}::ldexp`.
+    /// This is used for testing.
+    fn ldexpi(f: i64, exp: isize) -> Self;
+}
+
+impl TestableFloat for f32 {
+    fn ldexpi(f: i64, exp: isize) -> Self { f as Self * (exp as Self).exp2() }
+}
+
+impl TestableFloat for f64 {
+    fn ldexpi(f: i64, exp: isize) -> Self { f as Self * (exp as Self).exp2() }
+}
+
 fn check_exact_one<F, T>(mut f: F, x: i64, e: isize, tstr: &str, expected: &[u8], expectedk: i16)
-        where T: DecodableFloat + fmt::Display,
+        where T: TestableFloat,
               F: FnMut(&Decoded, &mut [u8], i16) -> (usize, i16) {
     // use a large enough buffer
     let mut buf = [b'_'; 1024];
-    let v: T = DecodableFloat::ldexpi(x, e);
+    let v: T = TestableFloat::ldexpi(x, e);
     let decoded = decode_finite(v);
 
     try_exact!(f(&decoded) => &mut buf, &expected, expectedk;