Auto merge of #75956 - jonas-schievink:lto-opt-sz, r=tmiasko

Fix -Clinker-plugin-lto with opt-levels s and z

Pass s and z as `-plugin-opt=O2` to the linker. This is what `-Os` and `-Oz` correspond to, apparently.

Fixes https://github.com/rust-lang/rust/issues/75940

3 files changed, 15 insertions, 3 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index 0ddf8bd316f..09dc51c57c2 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -221,10 +221,8 @@ impl<'a> GccLinker<'a> {
         let opt_level = match self.sess.opts.optimize {
             config::OptLevel::No => "O0",
             config::OptLevel::Less => "O1",
-            config::OptLevel::Default => "O2",
+            config::OptLevel::Default | config::OptLevel::Size | config::OptLevel::SizeMin => "O2",
             config::OptLevel::Aggressive => "O3",
-            config::OptLevel::Size => "Os",
-            config::OptLevel::SizeMin => "Oz",
         };
 
         self.linker_arg(&format!("-plugin-opt={}", opt_level));
diff --git a/src/test/ui/lto-opt-level-s.rs b/src/test/ui/lto-opt-level-s.rs
new file mode 100644
index 00000000000..a7d9d5024d3
--- /dev/null
+++ b/src/test/ui/lto-opt-level-s.rs
@@ -0,0 +1,7 @@
+// compile-flags: -Clinker-plugin-lto -Copt-level=s
+// build-pass
+// no-prefer-dynamic
+
+#![crate_type = "rlib"]
+
+pub fn foo() {}
diff --git a/src/test/ui/lto-opt-level-z.rs b/src/test/ui/lto-opt-level-z.rs
new file mode 100644
index 00000000000..bf1f5e2b263
--- /dev/null
+++ b/src/test/ui/lto-opt-level-z.rs
@@ -0,0 +1,7 @@
+// compile-flags: -Clinker-plugin-lto -Copt-level=z
+// build-pass
+// no-prefer-dynamic
+
+#![crate_type = "rlib"]
+
+pub fn foo() {}