From 855281c8871e43980fc41b54d1d5949a9863103d Mon Sep 17 00:00:00 2001
From: WANG Rui <wangrui@loongson.cn>
Date: Wed, 24 Dec 2025 16:04:58 +0800
Subject: [PATCH] Disable f16 on LoongArch for LLVM < 21

The `f16` type works on the LoongArch target starting from LLVM 21.
However, the current minimum supported external LLVM version is 20,
so `f16` must not be enabled on LoongArch for LLVM version < 21.
---
 compiler/rustc_codegen_llvm/src/llvm_util.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index a5a8f8e6a25e8..01181ce261842 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -383,6 +383,7 @@ fn update_target_reliable_float_cfg(sess: &Session, cfg: &mut TargetConfig) {
         // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
         (Arch::CSky, _) => false,
         (Arch::Hexagon, _) if major < 21 => false, // (fixed in llvm21)
+        (Arch::LoongArch32 | Arch::LoongArch64, _) if major < 21 => false, // (fixed in llvm21)
         (Arch::PowerPC | Arch::PowerPC64, _) => false,
         (Arch::Sparc | Arch::Sparc64, _) => false,
         (Arch::Wasm32 | Arch::Wasm64, _) => false,