disable some tests for non-x86_64 platforms

testcrate/src/lib.rs

@@ -9,6 +9,9 @@
 //! encounter. The randomized fuzz testing is specially designed to cover wide swaths of search
 //! space in as few iterations as possible. See `fuzz_values` in `testcrate/tests/misc.rs` for an
 //! example.
+//!
+//! Some floating point tests are only enabled on x86_64, because many other targets do not have
+//! correct rounding.
 #![no_std]
 
 use compiler_builtins::float::Float;

testcrate/tests/addsub.rs

@@ -91,6 +91,7 @@ macro_rules! float_sum {
     };
 }
 
+#[cfg(target_arch = "x86_64")]
 #[test]
 fn float_addsub() {
     use compiler_builtins::float::{

testcrate/tests/conv.rs

@@ -12,6 +12,7 @@ macro_rules! i_to_f {
     };
 }
 
+#[cfg(target_arch = "x86_64")]
 #[test]
 fn int_to_float() {
     use compiler_builtins::float::conv::{