Avoid inlining floor into rem_pio2

Possible workaround for
#976 (comment)

Inline assembly in the body of a function currently causes the compiler
to consider that function possibly unwinding, even if said asm
originated from inlining an `extern "C"` function. This patch wraps the
problematic callsite with `#[inline(never)]`.

Author: quaternic

libm/src/math/rem_pio2_large.rs

@@ -11,7 +11,7 @@
  * ====================================================
  */
 
-use super::{floor, scalbn};
+use super::scalbn;
 
 // initial value for jk
 const INIT_JK: [usize; 4] = [3, 4, 4, 6];
@@ -223,6 +223,14 @@ const PIO2: [f64; 8] = [
 /// independent of the exponent of the input.
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
 pub(crate) fn rem_pio2_large(x: &[f64], y: &mut [f64], e0: i32, prec: usize) -> i32 {
+    // FIXME(rust-lang/rust#144518): Inline assembly would cause `no_panic` to fail
+    // on the callers of this function. As a workaround, avoid inlining `floor` here
+    // when implemented with assembly.
+    #[cfg_attr(x86_no_sse, inline(never))]
+    extern "C" fn floor(x: f64) -> f64 {
+        super::floor(x)
+    }
+
     let x1p24 = f64::from_bits(0x4170000000000000); // 0x1p24 === 2 ^ 24
     let x1p_24 = f64::from_bits(0x3e70000000000000); // 0x1p_24 === 2 ^ (-24)