Enable f16 for LoongArch

Author: heiher

configure.rs

@@ -76,10 +76,8 @@ pub fn configure_f16_f128(target: &Target) {
         // Selection failure <https://github.com/llvm/llvm-project/issues/50374>
         "s390x" => false,
         // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
-        // FIXME(llvm20): loongarch fixed by <https://github.com/llvm/llvm-project/pull/107791>
         "csky" => false,
         "hexagon" => false,
-        "loongarch64" => false,
         "powerpc" | "powerpc64" => false,
         "sparc" | "sparc64" => false,
         "wasm32" | "wasm64" => false,

testcrate/build.rs

@@ -92,7 +92,7 @@ fn main() {
     }
 
     // These platforms do not have `__gnu_f2h_ieee` or `__gnu_h2f_ieee`.
-    if false {
+    if target.arch == "loongarch64" {
         features.insert(Feature::NoSysF16GnuConvert);
     }