diff --git a/modules/libcom/test/epicsCalcTest.cpp b/modules/libcom/test/epicsCalcTest.cpp
index 2492c95ba..25701b153 100644
--- a/modules/libcom/test/epicsCalcTest.cpp
+++ b/modules/libcom/test/epicsCalcTest.cpp
@@ -612,18 +612,12 @@ MAIN(epicsCalcTest)
     testExpr(0.0 + NaN);
     testExpr(Inf + 0.0);
     testExpr(Inf + Inf);
-#if defined(_WIN64) && defined(_MSC_VER)
+    // only test CALC as MSVC seems to incorrectly evaluate this expression at compile time.
+    // see note in epicsMathTest
     testCalc("Inf + -Inf", NaN);
-#else
-    testExpr(Inf + -Inf);
-#endif
     testExpr(Inf + NaN);
     testExpr(-Inf + 0.0);
-#if defined(_WIN64) && defined(_MSC_VER)
     testCalc("-Inf + Inf", NaN);
-#else
-    testExpr(-Inf + Inf);
-#endif
     testExpr(-Inf + -Inf);
     testExpr(-Inf + NaN);
     testExpr(NaN + 0.0);
diff --git a/modules/libcom/test/epicsMathTest.c b/modules/libcom/test/epicsMathTest.c
index 8ea763cf0..6d1fb85e8 100644
--- a/modules/libcom/test/epicsMathTest.c
+++ b/modules/libcom/test/epicsMathTest.c
@@ -32,23 +32,23 @@ MAIN(epicsMathTest)
     testOk1(epicsINF > 0.0);
     testOk1(epicsINF - epicsINF != 0.0);
 
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoBegin("Known failure on windows-x64");
+#if defined(_MSC_VER)
+    testTodoBegin("Known failure on windows (MSVC optimizer bug?)");
 #endif
     testOk1(epicsINF + -epicsINF != 0.0);
     testOk1(-epicsINF + epicsINF != 0.0);
-#if defined(_WIN64) && defined(_MSC_VER)
+#if defined(_MSC_VER)
     testTodoEnd();
 #endif
 
     testOk1(isnan(epicsINF - epicsINF));
 
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoBegin("Known failure on windows-x64");
+#if defined(_MSC_VER)
+    testTodoBegin("Known failure on windows (MSVC optimizer bug?)");
 #endif
     testOk1(isnan(epicsINF + -epicsINF));
     testOk1(isnan(-epicsINF + epicsINF));
-#if defined(_WIN64) && defined(_MSC_VER)
+#if defined(_MSC_VER)
     testTodoEnd();
 #endif
     
@@ -62,12 +62,12 @@ MAIN(epicsMathTest)
     testOk1(!(epicsNAN > epicsNAN));
     testOk1(isnan(epicsNAN - epicsNAN));
 
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoBegin("Known failure on windows-x64");
+#if defined(_MSC_VER)
+    testTodoBegin("Known failure on windows (MSVC optimizer bug?)");
 #endif
     testOk1(isnan(epicsNAN + -epicsNAN));
     testOk1(isnan(-epicsNAN + epicsNAN));
-#if defined(_WIN64) && defined(_MSC_VER)
+#if defined(_MSC_VER)
     testTodoEnd();
 #endif