Add an attribute to check the number of lanes in a SIMD vector after monomorphization

Unify zero-length and oversized SIMD errors

compiler/rustc_codegen_gcc/src/context.rs

@@ -529,7 +529,10 @@ impl<'gcc, 'tcx> HasX86AbiOpt for CodegenCx<'gcc, 'tcx> {
 impl<'gcc, 'tcx> LayoutOfHelpers<'tcx> for CodegenCx<'gcc, '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.dcx().emit_fatal(respan(span, err.into_diagnostic()))
         } else {
             self.tcx.dcx().emit_fatal(ssa_errors::FailedToGetLayout { span, ty, err })
@@ -545,7 +548,9 @@ impl<'gcc, 'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'gcc, 'tcx> {
         span: Span,
         fn_abi_request: FnAbiRequest<'tcx>,
     ) -> ! {
-        if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
+        if let FnAbiError::Layout(LayoutError::SizeOverflow(_) | LayoutError::InvalidSimd { .. }) =
+            err
+        {
             self.tcx.dcx().emit_fatal(respan(span, err))
         } else {
             match fn_abi_request {