1 files changed, 81 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/libm/src/math/floor.rs b/vendor/compiler_builtins/libm/src/math/floor.rs
new file mode 100644
index 000000000..d09f9a1a1
--- /dev/null
+++ b/vendor/compiler_builtins/libm/src/math/floor.rs
@@ -0,0 +1,81 @@
+#![allow(unreachable_code)]
+use core::f64;
+
+const TOINT: f64 = 1. / f64::EPSILON;
+
+/// Floor (f64)
+///
+/// Finds the nearest integer less than or equal to `x`.
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn floor(x: f64) -> f64 {
+    // On wasm32 we know that LLVM's intrinsic will compile to an optimized
+    // `f64.floor` native instruction, so we can leverage this for both code size
+    // and speed.
+    llvm_intrinsically_optimized! {
+        #[cfg(target_arch = "wasm32")] {
+            return unsafe { ::core::intrinsics::floorf64(x) }
+        }
+    }
+    #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))]
+    {
+        //use an alternative implementation on x86, because the
+        //main implementation fails with the x87 FPU used by
+        //debian i386, probablly due to excess precision issues.
+        //basic implementation taken from https://github.com/rust-lang/libm/issues/219
+        use super::fabs;
+        if fabs(x).to_bits() < 4503599627370496.0_f64.to_bits() {
+            let truncated = x as i64 as f64;
+            if truncated > x {
+                return truncated - 1.0;
+            } else {
+                return truncated;
+            }
+        } else {
+            return x;
+        }
+    }
+    let ui = x.to_bits();
+    let e = ((ui >> 52) & 0x7ff) as i32;
+
+    if (e >= 0x3ff + 52) || (x == 0.) {
+        return x;
+    }
+    /* y = int(x) - x, where int(x) is an integer neighbor of x */
+    let y = if (ui >> 63) != 0 {
+        x - TOINT + TOINT - x
+    } else {
+        x + TOINT - TOINT - x
+    };
+    /* special case because of non-nearest rounding modes */
+    if e < 0x3ff {
+        force_eval!(y);
+        return if (ui >> 63) != 0 { -1. } else { 0. };
+    }
+    if y > 0. {
+        x + y - 1.
+    } else {
+        x + y
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use core::f64::*;
+
+    #[test]
+    fn sanity_check() {
+        assert_eq!(floor(1.1), 1.0);
+        assert_eq!(floor(2.9), 2.0);
+    }
+
+    /// The spec: https://en.cppreference.com/w/cpp/numeric/math/floor
+    #[test]
+    fn spec_tests() {
+        // Not Asserted: that the current rounding mode has no effect.
+        assert!(floor(NAN).is_nan());
+        for f in [0.0, -0.0, INFINITY, NEG_INFINITY].iter().copied() {
+            assert_eq!(floor(f), f);
+        }
+    }
+}