Disable f16 for LoongArch64

[heiher]

Disable f161 for LoongArch64 due to incorrect code generation on LLVM 19, which causes failures in testcrate/tests/conv.rs. This workaround will remain in place until llvm/llvm-project#109093 is merged or we upgrade to LLVM 20.

[tgross35]

Do tests pass if you only disable FFI calls here

compiler-builtins/testcrate/build.rs

Lines 55 to 66 in d4a3955

	if (target.arch == "aarch64" && target.os == "linux")
	|| target.arch.starts_with("arm")
	|| target.arch == "powerpc"
	|| target.arch == "powerpc64"
	|| target.arch == "powerpc64le"
	|| (target.arch == "x86" && !target.has_feature("sse"))
	|| target.os == "windows"
	// Linking says "error: function signature mismatch: __extendhfsf2" and seems to
	// think the signature is either `(i32) -> f32` or `(f32) -> f32`. See
	// <https://github.com/llvm/llvm-project/issues/96438>.
	|| target.arch == "wasm32"
	|| target.arch == "wasm64"

instead of disabling everything for the type?

[heiher]

Do tests pass if you only disable FFI calls here

compiler-builtins/testcrate/build.rs

Lines 55 to 66 in d4a3955

	if (target.arch == "aarch64" && target.os == "linux")
	|| target.arch.starts_with("arm")
	|| target.arch == "powerpc"
	|| target.arch == "powerpc64"
	|| target.arch == "powerpc64le"
	|| (target.arch == "x86" && !target.has_feature("sse"))
	|| target.os == "windows"
	// Linking says "error: function signature mismatch: __extendhfsf2" and seems to
	// think the signature is either `(i32) -> f32` or `(f32) -> f32`. See
	// <https://github.com/llvm/llvm-project/issues/96438>.
	|| target.arch == "wasm32"
	|| target.arch == "wasm64"

instead of disabling everything for the type?

No, they are still failing.

[tgross35]

Thanks for checking, I updated the comment but this lgtm

[tgross35]

If you need it in rust-lang/rust, this is released in 0.1.138 https://github.com/rust-lang/compiler-builtins/releases/tag/compiler_builtins-v0.1.138. Will probably be a few days before we can bump to that version since a few builtins updates are already queued.