From 9ca739e65a6f8269898d178c6371b1d6b96948ee Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Sun, 6 Oct 2024 23:36:22 -0400
Subject: [PATCH] cfg out checks in add and sub but not offset

...because the checks in offset found bugs in a crater run.
---
 core/src/ptr/const_ptr.rs | 4 ++++
 core/src/ptr/mut_ptr.rs   | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/core/src/ptr/const_ptr.rs b/core/src/ptr/const_ptr.rs
index 4727dc77d18d4..c9af7f13e46c4 100644
--- a/core/src/ptr/const_ptr.rs
+++ b/core/src/ptr/const_ptr.rs
@@ -887,6 +887,7 @@ impl<T: ?Sized> *const T {
     where
         T: Sized,
     {
+        #[cfg(debug_assertions)]
         #[inline]
         const fn runtime_add_nowrap(this: *const (), count: usize, size: usize) -> bool {
             #[inline]
@@ -905,6 +906,7 @@ impl<T: ?Sized> *const T {
             intrinsics::const_eval_select((this, count, size), comptime, runtime)
         }
 
+        #[cfg(debug_assertions)] // Expensive, and doesn't catch much in the wild.
         ub_checks::assert_unsafe_precondition!(
             check_language_ub,
             "ptr::add requires that the address calculation does not overflow",
@@ -993,6 +995,7 @@ impl<T: ?Sized> *const T {
     where
         T: Sized,
     {
+        #[cfg(debug_assertions)]
         #[inline]
         const fn runtime_sub_nowrap(this: *const (), count: usize, size: usize) -> bool {
             #[inline]
@@ -1010,6 +1013,7 @@ impl<T: ?Sized> *const T {
             intrinsics::const_eval_select((this, count, size), comptime, runtime)
         }
 
+        #[cfg(debug_assertions)] // Expensive, and doesn't catch much in the wild.
         ub_checks::assert_unsafe_precondition!(
             check_language_ub,
             "ptr::sub requires that the address calculation does not overflow",
diff --git a/core/src/ptr/mut_ptr.rs b/core/src/ptr/mut_ptr.rs
index 8dbce1fdb984e..e458bb4642fc6 100644
--- a/core/src/ptr/mut_ptr.rs
+++ b/core/src/ptr/mut_ptr.rs
@@ -971,6 +971,7 @@ impl<T: ?Sized> *mut T {
     where
         T: Sized,
     {
+        #[cfg(debug_assertions)]
         #[inline]
         const fn runtime_add_nowrap(this: *const (), count: usize, size: usize) -> bool {
             #[inline]
@@ -989,6 +990,7 @@ impl<T: ?Sized> *mut T {
             intrinsics::const_eval_select((this, count, size), comptime, runtime)
         }
 
+        #[cfg(debug_assertions)] // Expensive, and doesn't catch much in the wild.
         ub_checks::assert_unsafe_precondition!(
             check_language_ub,
             "ptr::add requires that the address calculation does not overflow",
@@ -1077,6 +1079,7 @@ impl<T: ?Sized> *mut T {
     where
         T: Sized,
     {
+        #[cfg(debug_assertions)]
         #[inline]
         const fn runtime_sub_nowrap(this: *const (), count: usize, size: usize) -> bool {
             #[inline]
@@ -1094,6 +1097,7 @@ impl<T: ?Sized> *mut T {
             intrinsics::const_eval_select((this, count, size), comptime, runtime)
         }
 
+        #[cfg(debug_assertions)] // Expensive, and doesn't catch much in the wild.
         ub_checks::assert_unsafe_precondition!(
             check_language_ub,
             "ptr::sub requires that the address calculation does not overflow",