From 3944b32e048b4362808ffa847cd2feb7d3525e06 Mon Sep 17 00:00:00 2001
From: Freddie Akeroyd <freddie.akeroyd@stfc.ac.uk>
Date: Mon, 17 Feb 2020 13:30:15 +0000
Subject: [PATCH] Add back in optimisation disable

---
 src/libCom/calc/calcPerform.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/libCom/calc/calcPerform.c b/src/libCom/calc/calcPerform.c
index 4a073c774..40e173b61 100644
--- a/src/libCom/calc/calcPerform.c
+++ b/src/libCom/calc/calcPerform.c
@@ -25,6 +25,7 @@
 #include "postfix.h"
 #include "postfixPvt.h"
 
+
 static double calcRandom(void);
 static int cond_search(const char **ppinst, int match);
 
@@ -32,6 +33,11 @@ static int cond_search(const char **ppinst, int match);
 #define PI 3.14159265358979323
 #endif
 
+/* Turn off global optimization for 64-bit MSVC builds */
+#if defined(_WIN32) && defined(_M_X64) && !defined(_MINGW)
+#  pragma optimize("g", off)
+#endif
+
 /* calcPerform
  *
  * Evalutate the postfix expression
@@ -392,6 +398,10 @@ epicsShareFunc long
     return 0;
 }
 
+#if defined(_WIN32) && defined(_M_X64) && !defined(_MINGW)
+#  pragma optimize("", on)
+#endif
+
 epicsShareFunc long
 calcArgUsage(const char *pinst, unsigned long *pinputs, unsigned long *pstores)
 {