From b53c717e6ab8e093e18fb1df9b8a8f22197469e1 Mon Sep 17 00:00:00 2001
From: Caleb Zulawski <caleb.zulawski@gmail.com>
Date: Tue, 16 Sep 2025 02:23:24 -0400
Subject: [PATCH] Add an attribute to check the number of lanes in a SIMD
 vector after monomorphization

Unify zero-length and oversized SIMD errors
---
 src/common.rs     | 9 +++++++--
 src/global_asm.rs | 5 ++++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/common.rs b/src/common.rs
index 2fbe5c02802a..81b1814605a1 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -439,7 +439,10 @@ pub(crate) fn anonymous_str(&mut self, msg: &str) -> Value {
 impl<'tcx> LayoutOfHelpers<'tcx> for FullyMonomorphizedLayoutCx<'tcx> {
     #[inline]
     fn handle_layout_err(&self, err: LayoutError<'tcx>, span: Span, ty: Ty<'tcx>) -> ! {
-        if let LayoutError::SizeOverflow(_) | LayoutError::ReferencesError(_) = err {
+        if let LayoutError::SizeOverflow(_)
+        | LayoutError::InvalidSimd { .. }
+        | LayoutError::ReferencesError(_) = err
+        {
             self.0.sess.dcx().span_fatal(span, err.to_string())
         } else {
             self.0
@@ -458,7 +461,9 @@ fn handle_fn_abi_err(
         span: Span,
         fn_abi_request: FnAbiRequest<'tcx>,
     ) -> ! {
-        if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
+        if let FnAbiError::Layout(LayoutError::SizeOverflow(_) | LayoutError::InvalidSimd { .. }) =
+            err
+        {
             self.0.sess.dcx().emit_fatal(Spanned { span, node: err })
         } else {
             match fn_abi_request {
diff --git a/src/global_asm.rs b/src/global_asm.rs
index 203b443269fa..1306c6aa5179 100644
--- a/src/global_asm.rs
+++ b/src/global_asm.rs
@@ -42,7 +42,10 @@ fn mangled_name(&self, instance: Instance<'tcx>) -> String {
 impl<'tcx> LayoutOfHelpers<'tcx> for GlobalAsmContext<'_, 'tcx> {
     #[inline]
     fn handle_layout_err(&self, err: LayoutError<'tcx>, span: Span, ty: Ty<'tcx>) -> ! {
-        if let LayoutError::SizeOverflow(_) | LayoutError::ReferencesError(_) = err {
+        if let LayoutError::SizeOverflow(_)
+        | LayoutError::InvalidSimd { .. }
+        | LayoutError::ReferencesError(_) = err
+        {
             self.tcx.sess.dcx().span_fatal(span, err.to_string())
         } else {
             self.tcx