1 files changed, 23 insertions, 10 deletions

diff --git a/library/stdarch/crates/assert-instr-macro/src/lib.rs b/library/stdarch/crates/assert-instr-macro/src/lib.rs
index f40f81fc033..702cd59c57f 100644
--- a/library/stdarch/crates/assert-instr-macro/src/lib.rs
+++ b/library/stdarch/crates/assert-instr-macro/src/lib.rs
@@ -48,14 +48,15 @@ pub fn assert_instr(
     use quote::ToTokens;
     let instr_str = instr
         .clone()
-        .into_tokens()
+        .into_token_stream()
         .to_string()
         .replace('.', "_")
         .replace(|c: char| c.is_whitespace(), "");
-    let assert_name = syn::Ident::from(
-        &format!("assert_{}_{}", name.as_ref(), instr_str)[..],
+    let assert_name = syn::Ident::new(
+        &format!("assert_{}_{}", name, instr_str),
+        name.span(),
     );
-    let shim_name = syn::Ident::from(format!("{}_shim", name.as_ref()));
+    let shim_name = syn::Ident::new(&format!("{}_shim", name), name.span());
     let mut inputs = Vec::new();
     let mut input_vals = Vec::new();
     let ret = &func.decl.output;
@@ -64,7 +65,7 @@ pub fn assert_instr(
             syn::FnArg::Captured(ref c) => c,
             ref v => panic!(
                 "arguments must not have patterns: `{:?}`",
-                v.clone().into_tokens()
+                v.clone().into_token_stream()
             ),
         };
         let ident = match capture.pat {
@@ -74,7 +75,7 @@ pub fn assert_instr(
         match invoc
             .args
             .iter()
-            .find(|a| a.0 == ident.as_ref())
+            .find(|a| *ident == a.0)
         {
             Some(&(_, ref tts)) => {
                 input_vals.push(quote! { #tts });
@@ -95,7 +96,7 @@ pub fn assert_instr(
                 .expect("attr.path.segments.first() failed")
                 .value()
                 .ident
-                .as_ref()
+                .to_string()
                 .starts_with("target")
         })
         .collect::<Vec<_>>();
@@ -108,15 +109,27 @@ pub fn assert_instr(
     } else {
         syn::LitStr::new("C", proc_macro2::Span::call_site())
     };
+    let shim_name_str = format!("{}{}", shim_name, assert_name);
     let to_test = quote! {
         #attrs
         unsafe extern #abi fn #shim_name(#(#inputs),*) #ret {
+            // The compiler in optimized mode by default runs a pass called
+            // "mergefunc" where it'll merge functions that look identical.
+            // Turns out some intrinsics produce identical code and they're
+            // folded together, meaning that one just jumps to another. This
+            // messes up our inspection of the disassembly of this function and
+            // we're not a huge fan of that.
+            //
+            // To thwart this pass and prevent functions from being merged we
+            // generate some code that's hopefully very tight in terms of
+            // codegen but is otherwise unique to prevent code from being
+            // folded.
+            ::stdsimd_test::_DONT_DEDUP = #shim_name_str;
             #name(#(#input_vals),*)
         }
     };
 
-    let tts: TokenStream = quote_spanned! {
-        proc_macro2::Span::call_site() =>
+    let tts: TokenStream = quote! {
         #[test]
         #[allow(non_snake_case)]
         #maybe_ignore
@@ -169,7 +182,7 @@ where
     T: Clone + IntoIterator,
     T::Item: quote::ToTokens,
 {
-    fn to_tokens(&self, tokens: &mut quote::Tokens) {
+    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
         for item in self.0.clone() {
             item.to_tokens(tokens);
         }