diff --git a/CMakeLists.txt b/CMakeLists.txt
index 795a23320..6e858a421 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -324,6 +324,15 @@ if (("${TARGET_ARCHITECTURE}" STREQUAL "x86_64") OR ("${TARGET_ARCHITECTURE}" ST
   unset(SSE_FLAGS)
 endif()
 
+# FIXME: Remove "x.." when CMP0054 is set to NEW
+if ("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC")
+  # This is the default for MSVC already but to replicate the
+  # python/Makefile build system behaviour this flag is set
+  # explicitly.
+  z3_add_cxx_flag("/fp:precise" REQUIRED)
+endif()
+# There doesn't seem to be an equivalent for clang/gcc
+
 ################################################################################
 # Threading support
 ################################################################################
diff --git a/contrib/cmake/cmake/z3_add_cxx_flag.cmake b/contrib/cmake/cmake/z3_add_cxx_flag.cmake
index 0c56bb0f6..8bffd7de3 100644
--- a/contrib/cmake/cmake/z3_add_cxx_flag.cmake
+++ b/contrib/cmake/cmake/z3_add_cxx_flag.cmake
@@ -7,6 +7,7 @@ function(z3_add_cxx_flag flag)
   string(REPLACE "/" "_" SANITIZED_FLAG_NAME "${SANITIZED_FLAG_NAME}")
   string(REPLACE "=" "_" SANITIZED_FLAG_NAME "${SANITIZED_FLAG_NAME}")
   string(REPLACE " " "_" SANITIZED_FLAG_NAME "${SANITIZED_FLAG_NAME}")
+  string(REPLACE ":" "_" SANITIZED_FLAG_NAME "${SANITIZED_FLAG_NAME}")
   unset(HAS_${SANITIZED_FLAG_NAME})
   CHECK_CXX_COMPILER_FLAG("${flag}" HAS_${SANITIZED_FLAG_NAME})
   if (z3_add_flag_REQUIRED AND NOT HAS_${SANITIZED_FLAG_NAME})