From 910e650f9b539a4d813dbd59ab2273690f5b646e Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 17 Apr 2026 15:38:33 +0200
Subject: [PATCH 1/2] Update the cc crate for rustc_llvm

Latest stacker needs a newer cc than 1.2.16 as older versions don't have
windows arm64ec support.
---
 Cargo.lock                     | 5 +++--
 compiler/rustc_llvm/Cargo.toml | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 873182dde9102..f2b11e384f3c9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -560,10 +560,11 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.2.16"
+version = "1.2.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be714c154be609ec7f5dad223a33bf1482fff90472de28f7362806e6d4832b8c"
+checksum = "e1354349954c6fc9cb0deab020f27f783cf0b604e8bb754dc4658ecf0d29c35f"
 dependencies = [
+ "find-msvc-tools",
  "jobserver",
  "libc",
  "shlex",
diff --git a/compiler/rustc_llvm/Cargo.toml b/compiler/rustc_llvm/Cargo.toml
index c9f8cd9495834..025299f4ae4eb 100644
--- a/compiler/rustc_llvm/Cargo.toml
+++ b/compiler/rustc_llvm/Cargo.toml
@@ -11,7 +11,7 @@ libc = "0.2.73"
 [build-dependencies]
 # tidy-alphabetical-start
 # `cc` updates often break things, so we pin it here.
-cc = "=1.2.16"
+cc = "=1.2.39"
 shlex = "1.3.0"
 # tidy-alphabetical-end
 

From 017dec40f689927e16dbae1b61cbb04cd9c8b879 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Fri, 8 May 2026 16:41:40 +0200
Subject: [PATCH 2/2] Build C code with LTO when LTO is enabled for rust code

---
 src/bootstrap/src/utils/cc_detect.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/bootstrap/src/utils/cc_detect.rs b/src/bootstrap/src/utils/cc_detect.rs
index 1ab2b92070c93..ca25e5dfc5762 100644
--- a/src/bootstrap/src/utils/cc_detect.rs
+++ b/src/bootstrap/src/utils/cc_detect.rs
@@ -25,7 +25,7 @@ use std::collections::HashSet;
 use std::iter;
 use std::path::{Path, PathBuf};
 
-use crate::core::config::{CompressDebuginfo, TargetSelection};
+use crate::core::config::{CompressDebuginfo, RustcLto, TargetSelection};
 use crate::utils::exec::{BootstrapCommand, command};
 use crate::{Build, CLang, GitRepo};
 
@@ -61,6 +61,15 @@ fn new_cc_build(build: &Build, target: TargetSelection) -> cc::Build {
             }
         }
     }
+    match build.config.rust_lto {
+        RustcLto::Off | RustcLto::ThinLocal => {}
+        RustcLto::Thin => {
+            cfg.flag_if_supported("-flto=thin");
+        }
+        RustcLto::Fat => {
+            cfg.flag_if_supported("-flto=full");
+        }
+    }
     cfg
 }