1 files changed, 40 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/libm/src/math/trunc.rs b/vendor/compiler_builtins/libm/src/math/trunc.rs
new file mode 100644
index 000000000..f7892a2c5
--- /dev/null
+++ b/vendor/compiler_builtins/libm/src/math/trunc.rs
@@ -0,0 +1,40 @@
+use core::f64;
+
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn trunc(x: f64) -> f64 {
+    // On wasm32 we know that LLVM's intrinsic will compile to an optimized
+    // `f64.trunc` native instruction, so we can leverage this for both code size
+    // and speed.
+    llvm_intrinsically_optimized! {
+        #[cfg(target_arch = "wasm32")] {
+            return unsafe { ::core::intrinsics::truncf64(x) }
+        }
+    }
+    let x1p120 = f64::from_bits(0x4770000000000000); // 0x1p120f === 2 ^ 120
+
+    let mut i: u64 = x.to_bits();
+    let mut e: i64 = (i >> 52 & 0x7ff) as i64 - 0x3ff + 12;
+    let m: u64;
+
+    if e >= 52 + 12 {
+        return x;
+    }
+    if e < 12 {
+        e = 1;
+    }
+    m = -1i64 as u64 >> e;
+    if (i & m) == 0 {
+        return x;
+    }
+    force_eval!(x + x1p120);
+    i &= !m;
+    f64::from_bits(i)
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn sanity_check() {
+        assert_eq!(super::trunc(1.1), 1.0);
+    }
+}