From 92e5c4f2dd3d51937f04d276a2aa166cf02c815b Mon Sep 17 00:00:00 2001
From: Chris Denton <chris@chrisdenton.dev>
Date: Wed, 1 Jul 2026 18:42:57 +0000
Subject: [PATCH] Disable f128 support on wasm

---
 compiler/rustc_codegen_llvm/src/llvm_util.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 73b7f699b606d..3f32e08854f91 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -401,6 +401,8 @@ fn update_target_reliable_float_cfg(sess: &Session, cfg: &mut TargetConfig) {
         (Arch::X86_64, Os::Windows) if *target_env == Env::Gnu && *target_abi != CfgAbi::Llvm => {
             false
         }
+        // Missing intrinsic <https://github.com/rust-lang/rust/issues/158673>
+        (Arch::Wasm32 | Arch::Wasm64, _) => false,
         // There are no known problems on other platforms, so the only requirement is that symbols
         // are available. `compiler-builtins` provides all symbols required for core `f128`
         // support, so this should work for everything else.