guard on math_errhandling & MATH_ERR{NO,EXCEPT} in fp assertions

Author: Flandini

libc/test/UnitTest/ErrnoSetterMatcher.h

@@ -189,7 +189,9 @@ static ErrnoSetterMatcherBuilder<RetT> returns(internal::Comparator<RetT> cmp) {
 
 // Used to check that `LIBC_NAMESPACE::libc_errno` was 0 or a specific
 // errno after executing `expr_or_statement` from a state where
-// `LIBC_NAMESPACE::libc_errno` was 0.
+// `LIBC_NAMESPACE::libc_errno` was 0. This is generic, so does not check
+// `math_errhandling & MATH_ERRNO` before errno matching, see FPTest.h for
+// assertions that check this.
 //
 // Expects `expected` to be convertible to int type.
 //

libc/test/UnitTest/FPExceptMatcher.h

@@ -147,8 +147,10 @@ class FPExceptCallableMatcher : public Matcher<bool> {
     expr_or_statement;                                                         \
     int expected_ = (expected);                                                \
     int mask_ = expected_ ? expected_ : FE_ALL_EXCEPT;                         \
-    EXPECT_FP_EXCEPT_EQUAL(expected_,                                          \
-                           LIBC_NAMESPACE::fputil::test_except(mask_));        \
+    if (math_errhandling & MATH_ERREXCEPT) {                                   \
+      EXPECT_FP_EXCEPT_EQUAL(expected_,                                        \
+                             LIBC_NAMESPACE::fputil::test_except(mask_));      \
+    }                                                                          \
   } while (0)
 
 #else // !LIBC_TEST_HAS_MATCHERS()

libc/test/UnitTest/FPTest.h

@@ -92,8 +92,11 @@ struct FPTest : public ErrnoSafeTest, public FEnvSafeTest {
 // were set
 #define EXPECT_ERRNO_FP_EXCEPT(expected_errno, expected_fexn,                  \
                                expr_or_statement)                              \
-  EXPECT_FP_EXCEPT((expected_fexn),                                            \
-                   EXPECT_ERRNO((expected_errno), expr_or_statement))
+  EXPECT_FP_EXCEPT((expected_fexn), EXPECT_ERRNO((expected_errno), {           \
+                     expr_or_statement;                                        \
+                     if (!(math_errhandling & MATH_ERRNO))                     \
+                       break;                                                  \
+                   }))
 
 #define EXPECT_NO_ERRNO_FP_EXCEPT(expr_or_statement)                           \
   EXPECT_ERRNO_FP_EXCEPT(0, 0, expr_or_statement)