add `-Zmin-function-alignment`

1 files changed, 5 insertions, 1 deletions

diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index f8454fd9960..f84cafb0c4f 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -472,7 +472,11 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
         let allocated_pointer = AttributeKind::AllocatedPointer.create_attr(cx.llcx);
         attributes::apply_to_llfn(llfn, AttributePlace::Argument(0), &[allocated_pointer]);
     }
-    if let Some(align) = codegen_fn_attrs.alignment {
+    // function alignment can be set globally with the `-Zmin-function-alignment=<n>` flag;
+    // the alignment from a `#[repr(align(<n>))]` is used if it specifies a higher alignment.
+    if let Some(align) =
+        Ord::max(cx.tcx.sess.opts.unstable_opts.min_function_alignment, codegen_fn_attrs.alignment)
+    {
         llvm::set_alignment(llfn, align);
     }
     if let Some(backchain) = backchain_attr(cx) {