Allow f16 and f128 on s390x and non-mingw windows

Author: bjorn3

src/lib.rs

@@ -182,36 +182,23 @@ impl CodegenBackend for CraneliftCodegenBackend {
         // FIXME do `unstable_target_features` properly
         let unstable_target_features = target_features.clone();
 
-        // FIXME(f16_f128): LLVM 20 (currently used by `rustc`) passes `f128` in XMM registers on
-        // Windows, whereas LLVM 21+ and Cranelift pass it indirectly. This means that `f128` won't
-        // work when linking against a LLVM-built sysroot.
-        let has_reliable_f128 = !sess.target.is_like_windows;
-        let has_reliable_f16 = match &*sess.target.arch {
-            // FIXME(f16_f128): LLVM 20 does not support `f16` on s390x, meaning the required
-            // builtins are not available in `compiler-builtins`.
-            "s390x" => false,
-            // FIXME(f16_f128): `rustc_codegen_llvm` currently disables support on Windows GNU
-            // targets due to GCC using a different ABI than LLVM. Therefore `f16` won't be
-            // available when using a LLVM-built sysroot.
-            "x86_64"
-                if sess.target.os == "windows"
-                    && sess.target.env == "gnu"
-                    && sess.target.abi != "llvm" =>
-            {
-                false
-            }
-            _ => true,
-        };
+        // FIXME(f16_f128): `rustc_codegen_llvm` currently disables support on Windows GNU
+        // targets due to GCC using a different ABI than LLVM. Therefore `f16` and `f128`
+        // won't be available when using a LLVM-built sysroot.
+        let has_reliable_f16_f128 = !(sess.target.arch == "x86_64"
+            && sess.target.os == "windows"
+            && sess.target.env == "gnu"
+            && sess.target.abi != "llvm");
 
         TargetConfig {
             target_features,
             unstable_target_features,
             // `rustc_codegen_cranelift` polyfills functionality not yet
             // available in Cranelift.
-            has_reliable_f16,
-            has_reliable_f16_math: has_reliable_f16,
-            has_reliable_f128,
-            has_reliable_f128_math: has_reliable_f128,
+            has_reliable_f16: has_reliable_f16_f128,
+            has_reliable_f16_math: has_reliable_f16_f128,
+            has_reliable_f128: has_reliable_f16_f128,
+            has_reliable_f128_math: has_reliable_f16_f128,
         }
     }