Auto merge of #150447 - WaffleLapkin:maybe-dangling-semantics, r=RalfJung

Implement `MaybeDangling` compiler support



Tracking issue: rust-lang/rust#118166



cc @RalfJung

Author: bors

src/type_of.rs

@@ -288,7 +288,9 @@ impl<'tcx> LayoutGccExt<'tcx> for TyAndLayout<'tcx> {
             Float(f) => cx.type_from_float(f),
             Pointer(address_space) => {
                 // If we know the alignment, pick something better than i8.
-                let pointee = if let Some(pointee) = self.pointee_info_at(cx, offset) {
+                let pointee = if let Some(pointee) = self.pointee_info_at(cx, offset)
+                    && pointee.align > rustc_abi::Align::ONE
+                {
                     cx.type_pointee_for_align(pointee.align)
                 } else {
                     cx.type_i8()