Reuse to_bits instead of badly reinventing it

Author: oli-obk

src/librustc_mir/hair/pattern/mod.rs

@@ -1092,27 +1092,24 @@ pub fn compare_const_vals<'a, 'tcx>(
                 (
                     Some(Value::ScalarPair(
                         Scalar::Ptr(ptr_a),
-                        Scalar::Bits {
-                            bits: size_a,
-                            defined: defined_a,
-                        },
+                        len_a,
                     )),
                     Some(Value::ScalarPair(
                         Scalar::Ptr(ptr_b),
-                        Scalar::Bits {
-                            bits: size_b,
-                            defined: defined_b,
-                        },
+                        len_b,
                     ))
-                ) if size_a == size_b &&
-                     ptr_a.offset.bytes() == 0 && ptr_b.offset.bytes() == 0 &&
-                     tcx.data_layout.pointer_size.bits() <= defined_a.into() &&
-                     tcx.data_layout.pointer_size.bits() <= defined_b.into() => {
-                    let map = tcx.alloc_map.lock();
-                    let alloc_a = map.unwrap_memory(ptr_a.alloc_id);
-                    let alloc_b = map.unwrap_memory(ptr_b.alloc_id);
-                    if alloc_a.bytes.len() as u64 == size_a as u64 {
-                        return from_bool(alloc_a == alloc_b);
+                ) if ptr_a.offset.bytes() == 0 && ptr_b.offset.bytes() == 0 => {
+                    if let Ok(len_a) = len_a.to_bits(tcx.data_layout.pointer_size) {
+                        if let Ok(len_b) = len_b.to_bits(tcx.data_layout.pointer_size) {
+                            if len_a == len_b {
+                                let map = tcx.alloc_map.lock();
+                                let alloc_a = map.unwrap_memory(ptr_a.alloc_id);
+                                let alloc_b = map.unwrap_memory(ptr_b.alloc_id);
+                                if alloc_a.bytes.len() as u128 == len_a {
+                                    return from_bool(alloc_a == alloc_b);
+                                }
+                            }
+                        }
                     }
                 }
                 _ => (),