Merge ~freddie-akeroyd/epics-base:nan_inf_tests into ~epics-core/epics-base/+git/epics-base:7.0

[Freddie Akeroyd]

Change tests to be more "a + -b" like than "a + -a" to avoid compiler optimisation issues

[Andrew Johnson (anj)]

Group 10/4:

Suggest epicsCalcTest() should compare the string expression against the known expected result (for inf/nan calculations) so don't use Freddie's change as currently written to this file.

The epicsMathTest() changes are tricking the optimizer, which is a brittle thing. Idea is to concentrate these kinds of tests in this file, to document the known issues. As a result removing the compiler checks and calls to testToDo() from here is less helpful, we'd still like to see those until we stop building on compilers that fail. Having ToDo tests pass isn't a problem.

AI on MAD to merge and fix this.

review: Needs Fixing

[mdavidsaver (mdavidsaver)]

Superseded by already merged changes.

Unmerged commits

e0e6c19... by Freddie Akeroyd on 2019-09-30

Use additional local NaN/Inf in binary operations

This is to avoid issues with evaluating e.g. Inf + -Inf with
some compilers. The form "a + -b" more reflects likely
situations than "a + -a"

diff --git a/modules/libcom/test/epicsCalcTest.cpp b/modules/libcom/test/epicsCalcTest.cpp
index 2492c95..9edc7c6 100644
--- a/modules/libcom/test/epicsCalcTest.cpp
+++ b/modules/libcom/test/epicsCalcTest.cpp
@@ -294,6 +294,13 @@ static inline double MIN(double a, double b, double c, double d, double e,
 MAIN(epicsCalcTest)
 {
     int repeat;
+    /*
+     * we need to create these to avoid issues with "NaN + -NaN" etc
+     * and compiler optimisation. In the real world we would see a + -b
+     * rather than a + -a
+     * calc expressions are case insensive, so we can use "NaN + -NAN" in C
+     */
+    float inf = Inf, nan = NaN;
     const double a=1.0, b=2.0, c=3.0, d=4.0, e=5.0, f=6.0,
 		 g=7.0, h=8.0, i=9.0, j=10.0, k=11.0, l=12.0;
     
@@ -612,19 +619,11 @@ MAIN(epicsCalcTest)
     testExpr(0.0 + NaN);
     testExpr(Inf + 0.0);
     testExpr(Inf + Inf);
-#if defined(_WIN64) && defined(_MSC_VER)
-    testCalc("Inf + -Inf", NaN);
-#else
-    testExpr(Inf + -Inf);
-#endif
+    testExpr(Inf + -inf);
     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 + inf);
+    testExpr(-Inf + -inf);
     testExpr(-Inf + NaN);
     testExpr(NaN + 0.0);
     testExpr(NaN + Inf);
@@ -638,11 +637,11 @@ MAIN(epicsCalcTest)
     testExpr(0.0 - NaN);
     testExpr(Inf - 0.0);
     testExpr(Inf - Inf);
-    testExpr(Inf - -Inf);
+    testExpr(Inf - -inf);
     testExpr(Inf - NaN);
     testExpr(-Inf - 0.0);
-    testExpr(-Inf - Inf);
-    testExpr(-Inf - -Inf);
+    testExpr(-Inf - inf);
+    testExpr(-Inf - -inf);
     testExpr(-Inf - NaN);
     testExpr(NaN - 0.0);
     testExpr(NaN - Inf);
diff --git a/modules/libcom/test/epicsMathTest.c b/modules/libcom/test/epicsMathTest.c
index 8ea763c..b3e67cf 100644
--- a/modules/libcom/test/epicsMathTest.c
+++ b/modules/libcom/test/epicsMathTest.c
@@ -20,6 +20,13 @@ MAIN(epicsMathTest)
     double huge = 1e300;
     double tiny = 1e-300;
     double c;
+    /*
+     * we need to create these to avoid issues with "NaN + -NaN" etc and
+     * compiler optimisation. In the real world we would
+     * see a + -b rather than a + -a
+     */
+    float epicsINF_ = epicsINF;
+    float epicsNAN_ = epicsNAN;
     
     testPlan(35);
     
@@ -28,29 +35,17 @@ MAIN(epicsMathTest)
     
     testOk1(!isnan(epicsINF));
     testOk1(isinf(epicsINF));
-    testOk1(epicsINF == epicsINF);
+    testOk1(epicsINF == epicsINF_);
     testOk1(epicsINF > 0.0);
-    testOk1(epicsINF - epicsINF != 0.0);
+    testOk1(epicsINF - epicsINF_ != 0.0);
 
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoBegin("Known failure on windows-x64");
-#endif
-    testOk1(epicsINF + -epicsINF != 0.0);
-    testOk1(-epicsINF + epicsINF != 0.0);
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoEnd();
-#endif
+    testOk1(epicsINF + -epicsINF_ != 0.0);
+    testOk1(-epicsINF + epicsINF_ != 0.0);
 
     testOk1(isnan(epicsINF - epicsINF));
 
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoBegin("Known failure on windows-x64");
-#endif
-    testOk1(isnan(epicsINF + -epicsINF));
-    testOk1(isnan(-epicsINF + epicsINF));
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoEnd();
-#endif
+    testOk1(isnan(epicsINF + -epicsINF_));
+    testOk1(isnan(-epicsINF + epicsINF_));
     
     testOk1(isnan(epicsNAN));
     testOk1(!isinf(epicsNAN));
@@ -62,14 +57,8 @@ MAIN(epicsMathTest)
     testOk1(!(epicsNAN > epicsNAN));
     testOk1(isnan(epicsNAN - epicsNAN));
 
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoBegin("Known failure on windows-x64");
-#endif
-    testOk1(isnan(epicsNAN + -epicsNAN));
-    testOk1(isnan(-epicsNAN + epicsNAN));
-#if defined(_WIN64) && defined(_MSC_VER)
-    testTodoEnd();
-#endif
+    testOk1(isnan(epicsNAN + -epicsNAN_));
+    testOk1(isnan(-epicsNAN + epicsNAN_));
     
     c = huge / tiny;
     testOk(!isnan(c), "!isnan(1e300 / 1e-300)");