From bb91d99e1b5bbce04cdf3f34abac454564420a63 Mon Sep 17 00:00:00 2001
From: Matthew Kennedy <matthewkennedy@outlook.com>
Date: Fri, 15 Jul 2022 15:17:57 -0700
Subject: [PATCH] isnan.h

---
 util/include/rusefi/interpolation.h |  1 +
 util/include/rusefi/isnan.h         | 14 ++++++++++++++
 2 files changed, 15 insertions(+)
 create mode 100644 util/include/rusefi/isnan.h

diff --git a/util/include/rusefi/interpolation.h b/util/include/rusefi/interpolation.h
index 7952cba..da57131 100644
--- a/util/include/rusefi/interpolation.h
+++ b/util/include/rusefi/interpolation.h
@@ -2,6 +2,7 @@
 
 #include <cstdint>
 
+#include "isnan.h"
 #include "scaled_channel.h"
 
 namespace priv {
diff --git a/util/include/rusefi/isnan.h b/util/include/rusefi/isnan.h
new file mode 100644
index 0000000..026f1c2
--- /dev/null
+++ b/util/include/rusefi/isnan.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#if defined(__cplusplus) && defined(__OPTIMIZE__)
+#include <type_traits>
+// "g++ -O2" version, adds more strict type check and yet no "strict-aliasing" warnings!
+#define cisnan(f) ({ \
+	static_assert(sizeof(f) == sizeof(int32_t)); \
+	union cisnanu_t { std::remove_reference_t<decltype(f)> __f; int32_t __i; } __cisnan_u = { f }; \
+	__cisnan_u.__i == 0x7FC00000; \
+})
+#else
+// "g++ -O0" or other C++/C compilers
+#define cisnan(f) (*(((int*) (&f))) == 0x7FC00000)
+#endif /* __cplusplus && __OPTIMIZE__ */