From 6a9b179fafdbfa038fe42e710d8b027711c6f17d Mon Sep 17 00:00:00 2001
From: Antoni Boucher <bouanto@zoho.com>
Date: Sat, 25 Jul 2026 15:06:31 -0400
Subject: [PATCH] Send -fno-lto when linker plugin LTO is not requested to
 avoid having GCC do LTO when using rustc_codegen_gcc

---
 compiler/rustc_codegen_ssa/src/back/linker.rs |  9 ++++++++-
 tests/run-make/fno-lto/main.rs                |  1 +
 tests/run-make/fno-lto/rmake.rs               | 17 +++++++++++++++++
 tests/run-make/linker-warning/rmake.rs        |  1 +
 4 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 tests/run-make/fno-lto/main.rs
 create mode 100644 tests/run-make/fno-lto/rmake.rs

diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index 15f0c450f55f8..515d3be2c4a49 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -900,7 +900,14 @@ impl<'a> Linker for GccLinker<'a> {
     fn linker_plugin_lto(&mut self) {
         match self.sess.opts.cg.linker_plugin_lto {
             LinkerPluginLto::Disabled => {
-                // Nothing to do
+                // GCC, when used as a linker, will perform LTO even without -flto when it sees
+                // object files with the GCC IR (which can happen when using rustc_codegen_gcc).
+                // Since the std is compiled with -Cembed-bitcode=yes, any program using the std
+                // will have the linker do LTO.
+                // So, we disable this with -fno-lto when linker plugin LTO is not requested.
+                if self.is_cc() && self.codegen_backend == "gcc" {
+                    self.cc_arg("-fno-lto");
+                }
             }
             LinkerPluginLto::LinkerPluginAuto => {
                 self.push_linker_plugin_lto_args(None);
diff --git a/tests/run-make/fno-lto/main.rs b/tests/run-make/fno-lto/main.rs
new file mode 100644
index 0000000000000..f328e4d9d04c3
--- /dev/null
+++ b/tests/run-make/fno-lto/main.rs
@@ -0,0 +1 @@
+fn main() {}
diff --git a/tests/run-make/fno-lto/rmake.rs b/tests/run-make/fno-lto/rmake.rs
new file mode 100644
index 0000000000000..db6fe7e6797f5
--- /dev/null
+++ b/tests/run-make/fno-lto/rmake.rs
@@ -0,0 +1,17 @@
+//@ needs-target-std
+//@ ignore-msvc
+//@ ignore-wasm
+//@ needs-backends: gcc
+
+use run_make_support::rustc;
+
+fn main() {
+    rustc().input("main.rs").print("link-args").run_unchecked().assert_stdout_contains("-fno-lto");
+
+    rustc()
+        .input("main.rs")
+        .arg("-Clinker-plugin-lto")
+        .print("link-args")
+        .run_unchecked()
+        .assert_stdout_not_contains("-fno-lto");
+}
diff --git a/tests/run-make/linker-warning/rmake.rs b/tests/run-make/linker-warning/rmake.rs
index b25d892507907..d183d115a55e1 100644
--- a/tests/run-make/linker-warning/rmake.rs
+++ b/tests/run-make/linker-warning/rmake.rs
@@ -1,4 +1,5 @@
 //@ ignore-cross-compile (need to run fake linker)
+//@ ignore-backends: gcc
 
 use run_make_support::{Rustc, diff, regex, rustc};