Sync from rust 1459b3128e288a85fcc4dd1fee7ada2cdcf28794

Author: bjorn3

src/base.rs

@@ -336,17 +336,10 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
                 crate::abi::codegen_return(fx);
             }
             TerminatorKind::Assert { cond, expected, msg, target, cleanup: _ } => {
-                if !fx.tcx.sess.overflow_checks() {
-                    let overflow_not_to_check = match msg {
-                        AssertKind::OverflowNeg(..) => true,
-                        AssertKind::Overflow(op, ..) => op.is_checkable(),
-                        _ => false,
-                    };
-                    if overflow_not_to_check {
-                        let target = fx.get_block(*target);
-                        fx.bcx.ins().jump(target, &[]);
-                        continue;
-                    }
+                if !fx.tcx.sess.overflow_checks() && msg.is_optional_overflow_check() {
+                    let target = fx.get_block(*target);
+                    fx.bcx.ins().jump(target, &[]);
+                    continue;
                 }
                 let cond = codegen_operand(fx, cond).load_scalar(fx);
 
@@ -706,6 +699,10 @@ fn codegen_stmt<'tcx>(
                     let operand = codegen_operand(fx, operand);
                     operand.coerce_dyn_star(fx, lval);
                 }
+                Rvalue::Cast(CastKind::Transmute, ref operand, _to_ty) => {
+                    let operand = codegen_operand(fx, operand);
+                    lval.write_cvalue_transmute(fx, operand);
+                }
                 Rvalue::Discriminant(place) => {
                     let place = codegen_place(fx, place);
                     let value = place.to_cvalue(fx);

src/intrinsics/mod.rs

@@ -557,16 +557,6 @@ fn codegen_regular_intrinsic_call<'tcx>(
             fx.bcx.ins().band(ptr, mask);
         }
 
-        sym::transmute => {
-            intrinsic_args!(fx, args => (from); intrinsic);
-
-            if ret.layout().abi.is_uninhabited() {
-                crate::base::codegen_panic(fx, "Transmuting to uninhabited type.", source_info);
-                return;
-            }
-
-            ret.write_cvalue_transmute(fx, from);
-        }
         sym::write_bytes | sym::volatile_set_memory => {
             intrinsic_args!(fx, args => (dst, val, count); intrinsic);
             let val = val.load_scalar(fx);

src/vtable.rs

@@ -48,9 +48,7 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
 ) -> (Pointer, Value) {
     let (ptr, vtable) = 'block: {
         if let Abi::Scalar(_) = arg.layout().abi {
-            'descend_newtypes: while !arg.layout().ty.is_unsafe_ptr()
-                && !arg.layout().ty.is_region_ptr()
-            {
+            'descend_newtypes: while !arg.layout().ty.is_unsafe_ptr() && !arg.layout().ty.is_ref() {
                 for i in 0..arg.layout().fields.count() {
                     let field = arg.value_field(fx, mir::Field::new(i));
                     if !field.layout().is_zst() {