From fe8b8a08911d254824d3c03253d773d51d242996 Mon Sep 17 00:00:00 2001
From: Matthew Parkinson <mattpark@microsoft.com>
Date: Sun, 12 Apr 2020 08:56:02 +0100
Subject: [PATCH] Improved assume defines.

---
 src/ds/defines.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/ds/defines.h b/src/ds/defines.h
index f697e1f..f22dd64 100644
--- a/src/ds/defines.h
+++ b/src/ds/defines.h
@@ -62,6 +62,12 @@ namespace snmalloc
 #else
 #  if __has_builtin(__builtin_assume)
 #    define SNMALLOC_ASSUME(x) __builtin_assume((x))
+#  elif defined(_MSC_VER)
+#    define SNMALLOC_ASSUME(x) __assume((x));
+#  elif defined(__GNUC__)
+#    define SNMALLOC_ASSUME(x) \
+      if (!(x)) \
+        __builtin_unreachable();
 #  else
 #    define SNMALLOC_ASSUME(x) \
       do \