Merge pull request #730 from tgross35/f16-f128-config-update

Disable `f16` on platforms that have recursion problems

Author: tgross35

configure.rs

@@ -51,31 +51,46 @@ impl Target {
 /// Configure whether or not `f16` and `f128` support should be enabled.
 pub fn configure_f16_f128(target: &Target) {
     // Set whether or not `f16` and `f128` are supported at a basic level by LLVM. This only means
-    // that the backend will not crash when using these types. This does not mean that the
-    // backend does the right thing, or that the platform doesn't have ABI bugs.
+    // that the backend will not crash when using these types and generates code that can be called
+    // without crashing (no infinite recursion). This does not mean that the platform doesn't have
+    // ABI or other bugs.
     //
     // We do this here rather than in `rust-lang/rust` because configuring via cargo features is
     // not straightforward.
     //
     // Original source of this list:
     // <https://github.com/rust-lang/compiler-builtins/pull/652#issuecomment-2266151350>
-    let (f16_ok, f128_ok) = match target.arch.as_str() {
-        // `f16` and `f128` both crash <https://github.com/llvm/llvm-project/issues/94434>
-        "arm64ec" => (false, false),
-        // `f16` crashes <https://github.com/llvm/llvm-project/issues/50374>
-        "s390x" => (false, true),
-        // FIXME(llvm): `f16` test failures fixed by <https://github.com/llvm/llvm-project/pull/107791>
-        "loongarch64" => (false, true),
-        // `f128` crashes <https://github.com/llvm/llvm-project/issues/96432>
-        "mips64" | "mips64r6" => (true, false),
-        // `f128` crashes <https://github.com/llvm/llvm-project/issues/101545>
-        "powerpc64" if &target.os == "aix" => (true, false),
-        // `f128` crashes <https://github.com/llvm/llvm-project/issues/41838>
-        "sparc" => (true, false),
-        // `f16` miscompiles <https://github.com/llvm/llvm-project/issues/96438>
-        "wasm32" | "wasm64" => (false, true),
+    let f16_enabled = match target.arch.as_str() {
+        // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
+        "arm64ec" => false,
+        // Selection failure <https://github.com/llvm/llvm-project/issues/50374>
+        "s390x" => false,
+        // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
+        // FIXME(llvm): loongarch fixed by <https://github.com/llvm/llvm-project/pull/107791>
+        "csky" => false,
+        "hexagon" => false,
+        "loongarch64" => false,
+        "mips" | "mips64" | "mips32r6" | "mips64r6" => false,
+        "powerpc" | "powerpc64" => false,
+        "sparc" | "sparc64" => false,
+        "wasm32" | "wasm64" => false,
         // Most everything else works as of LLVM 19
-        _ => (true, true),
+        _ => true,
+    };
+
+    let f128_enabled = match target.arch.as_str() {
+        // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
+        "arm64ec" => false,
+        // Selection failure <https://github.com/llvm/llvm-project/issues/96432>
+        "mips64" | "mips64r6" => false,
+        // Selection failure <https://github.com/llvm/llvm-project/issues/95471>
+        "nvptx64" => false,
+        // Selection failure <https://github.com/llvm/llvm-project/issues/101545>
+        "powerpc64" if &target.os == "aix" => false,
+        // Selection failure <https://github.com/llvm/llvm-project/issues/41838>
+        "sparc" => false,
+        // Most everything else works as of LLVM 19
+        _ => true,
     };
 
     // If the feature is set, disable these types.
@@ -84,11 +99,11 @@ pub fn configure_f16_f128(target: &Target) {
     println!("cargo::rustc-check-cfg=cfg(f16_enabled)");
     println!("cargo::rustc-check-cfg=cfg(f128_enabled)");
 
-    if f16_ok && !disable_both {
+    if f16_enabled && !disable_both {
         println!("cargo::rustc-cfg=f16_enabled");
     }
 
-    if f128_ok && !disable_both {
+    if f128_enabled && !disable_both {
         println!("cargo::rustc-cfg=f128_enabled");
     }
 }