Rollup merge of #33892 - seanmonstar:slice-eq-ptr, r=alexcrichton

core: check pointer equality when comparing byte slices

If pointer address and length are the same, it should be the same slice.

In experiments, I've seen that this doesn't happen as often in debug builds, but release builds seem to optimize to using a single pointer more often.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index 72d32607638..b6ae6fde1e3 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -1830,6 +1830,9 @@ impl<A> SlicePartialEq<A> for [A]
         if self.len() != other.len() {
             return false;
         }
+        if self.as_ptr() == other.as_ptr() {
+            return true;
+        }
         unsafe {
             let size = mem::size_of_val(self);
             memcmp(self.as_ptr() as *const u8,