Auto merge of #106474 - erikdesjardins:noalias, r=bjorn3

cleanup: handle -Zmutable-noalias like -Zbox-noalias

r? `@bjorn3`

cc `@RalfJung` this will conflict with #106180

1 files changed, 0 insertions, 10 deletions

diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index a6fd2a7de6b..546540dfd76 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -34,13 +34,6 @@ pub trait ArgAttributesExt {
     );
 }
 
-fn should_use_mutable_noalias(cx: &CodegenCx<'_, '_>) -> bool {
-    // LLVM prior to version 12 had known miscompiles in the presence of
-    // noalias attributes (see #54878), but we don't support earlier
-    // versions at all anymore. We now enable mutable noalias by default.
-    cx.tcx.sess.opts.unstable_opts.mutable_noalias.unwrap_or(true)
-}
-
 const ABI_AFFECTING_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 1] =
     [(ArgAttribute::InReg, llvm::AttributeKind::InReg)];
 
@@ -88,9 +81,6 @@ fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'
                 attrs.push(llattr.create_attr(cx.llcx));
             }
         }
-        if regular.contains(ArgAttribute::NoAliasMutRef) && should_use_mutable_noalias(cx) {
-            attrs.push(llvm::AttributeKind::NoAlias.create_attr(cx.llcx));
-        }
     } else if cx.tcx.sess.opts.unstable_opts.sanitizer.contains(SanitizerSet::MEMORY) {
         // If we're not optimising, *but* memory sanitizer is on, emit noundef, since it affects
         // memory sanitizer's behavior.