From 6b09a93566cc891a56a8f9bb68a25d16ca4d91d3 Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Fri, 27 Sep 2024 18:35:30 -0400
Subject: [PATCH] Enable `f16` tests on non-GNU Windows

There is a MinGW ABI bug that prevents `f16` and `f128` from being
usable on `windows-gnu` targets. This does not affect MSVC; however, we
have `f16` and `f128` tests disabled on all Windows targets.

Update the gating to only affect `windows-gnu`, which means `f16` tests
will be enabled. There is no effect for `f128` since the default
fallback is `false`.
---
 library/std/build.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/library/std/build.rs b/library/std/build.rs
index 5da470c6462..7d37d4e9d7d 100644
--- a/library/std/build.rs
+++ b/library/std/build.rs
@@ -101,7 +101,7 @@ fn main() {
         // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
         ("arm64ec", _) => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
-        ("x86_64", "windows") => false,
+        ("x86_64", "windows") if target_env == "gnu" => false,
         // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
         ("csky", _) => false,
         ("hexagon", _) => false,
@@ -129,10 +129,10 @@ fn main() {
         // ABI unsupported  <https://github.com/llvm/llvm-project/issues/41838>
         ("sparc", _) => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
-        ("x86_64", "windows") => false,
+        ("x86_64", "windows") if target_env == "gnu" => false,
         // 64-bit Linux is about the only platform to have f128 symbols by default
         (_, "linux") if target_pointer_width == 64 => true,
-        // Same as for f16, except MacOS is also missing f128 symbols.
+        // Almost all OSs are missing symbol. compiler-builtins will have to add them.
         _ => false,
     };