Merge pull request #11485 from mixxxdj/denormals_test_fix

Fix MathUtil.Denormals with clang 15/16
mixxxdj · Apr 17, 2023 · 0c4e1e3 · 0c4e1e3
2 parents 16c4343 + c9342ec
commit 0c4e1e3
Showing 1 changed file with 11 additions and 4 deletions.
diff --git a/src/test/mathutiltest.cpp b/src/test/mathutiltest.cpp
@@ -64,19 +64,26 @@ TEST_F(MathUtilTest, Denormal) {
     _MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_OFF);
     _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_OFF);
 
-    volatile float fDenormal = std::numeric_limits<float>::min() / 2.0f;
+    // Note: The volatile keyword makes sure that the division is executed on the target
+    // and not by the pre-processor. In case of clang >= 15 the pre-processor flushes to
+    // zero with -ffast-math enabled.
+    volatile float fDenormal = std::numeric_limits<float>::min();
+    fDenormal /= 2.0f;
     EXPECT_NE(0.0f, fDenormal);
 
-    volatile double dDenormal = std::numeric_limits<double>::min() / 2.0;
+    volatile double dDenormal = std::numeric_limits<double>::min();
+    dDenormal /= 2.0;
     EXPECT_NE(0.0, dDenormal);
 
     _MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
     _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
 
-    fDenormal = std::numeric_limits<float>::min() / 2.0f;
+    fDenormal = std::numeric_limits<float>::min();
+    fDenormal /= 2.0f;
     EXPECT_EQ(0.0f, fDenormal);
 
-    dDenormal = std::numeric_limits<double>::min() / 2.0;
+    dDenormal = std::numeric_limits<double>::min();
+    dDenormal /= 2.0;
     EXPECT_EQ(0.0, dDenormal);
 
 #endif