From f3e470c3e4caee7b947fd49f26a5add170ea6265 Mon Sep 17 00:00:00 2001
From: Nathaniel Wesley Filardo <nfilardo@microsoft.com>
Date: Sun, 12 Nov 2023 00:22:50 +0000
Subject: [PATCH] realloc: ASSUME non-NULL source pointer for memcpy

NULL has size zero, which rounds up to zero, and so would have been handled.
---
 src/snmalloc/override/libc.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/snmalloc/override/libc.h b/src/snmalloc/override/libc.h
index 05a82ec..a7fd211 100644
--- a/src/snmalloc/override/libc.h
+++ b/src/snmalloc/override/libc.h
@@ -74,7 +74,10 @@ namespace snmalloc::libc
       // Guard memcpy as GCC is assuming not nullptr for ptr after the memcpy
       // otherwise.
       if (SNMALLOC_UNLIKELY(sz != 0))
+      {
+        SNMALLOC_ASSUME(ptr != nullptr);
         ::memcpy(p, ptr, sz);
+      }
       a.dealloc(ptr);
     }
     else if (SNMALLOC_LIKELY(size == 0))
@@ -174,4 +177,4 @@ namespace snmalloc::libc
     *memptr = p;
     return 0;
   }
-} // namespace snmalloc::libc
\ No newline at end of file
+} // namespace snmalloc::libc