From 25a2ba2ee4febf9c22f7add7e14a0a50b3fd984d Mon Sep 17 00:00:00 2001
From: Scott McMurray <scottmcm@users.noreply.github.com>
Date: Sat, 26 Aug 2023 17:42:59 -0700
Subject: [PATCH] Use `preserve_mostcc` for `extern "rust-cold"`

As experimentation in 115242 has shown looks better than `coldcc`.

And *don't* use a different convention for cold on Windows, because that actually ends up making things worse.

cc tracking issue 97544
---
 src/abi/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/abi/mod.rs b/src/abi/mod.rs
index b7f56a2986c..5d775b9b532 100644
--- a/src/abi/mod.rs
+++ b/src/abi/mod.rs
@@ -39,7 +39,7 @@ fn clif_sig_from_fn_abi<'tcx>(
 pub(crate) fn conv_to_call_conv(sess: &Session, c: Conv, default_call_conv: CallConv) -> CallConv {
     match c {
         Conv::Rust | Conv::C => default_call_conv,
-        Conv::RustCold => CallConv::Cold,
+        Conv::Cold | Conv::PreserveMost | Conv::PreserveAll => CallConv::Cold,
         Conv::X86_64SysV => CallConv::SystemV,
         Conv::X86_64Win64 => CallConv::WindowsFastcall,