Add regression test for #105626

tests/ui/numbers-arithmetic/issue-105626.rs

@@ -0,0 +1,17 @@
+// run-pass
+// only-x86
+// min-system-llvm-version: 16
+// compile-flags: -Ctarget-feature=+sse2
+
+use std::hint::black_box;
+
+fn main() {
+    let n: i64 = black_box(0x3fffffdfffffff);
+    let r = f32::from_bits(0x5a7fffff);
+
+    assert_ne!((n as f64) as f32, n as f32);
+
+    // FIXME: these assertions fail if only x87 is enabled
+    assert_eq!(n as i64 as f32, r);
+    assert_eq!(n as u64 as f32, r);
+}