git: 2b9dbcd390df - main - lib/msun/tests: Skip fenv_test:masking if exceptions can't be trapped

[Alex Richardson]

The branch main has been updated by arichardson:

URL: https://cgit.FreeBSD.org/src/commit/?id=2b9dbcd390dfbd573d3403360a36c5ade9815266

commit 2b9dbcd390dfbd573d3403360a36c5ade9815266
Author:     Alex Richardson <arichardson at FreeBSD.org>
AuthorDate: 2021-03-22 11:53:40 +0000
Commit:     Alex Richardson <arichardson at FreeBSD.org>
CommitDate: 2021-03-22 11:55:07 +0000

    lib/msun/tests: Skip fenv_test:masking if exceptions can't be trapped
    
    Some CPUs (e.g. AArch64 QEMU) cannot trap on floating point exceptions and
    therefore ignore the writes to the floating point control register inside
    feenableexcept(). If no exceptions are enabled after
    feenableexcept(FE_ALL_EXCEPT), we can assume that the CPU does not
    support exceptions and we can then skip the test.
    
    Reviewed By:    dim
    Differential Revision: https://reviews.freebsd.org/D29095
---
 lib/msun/tests/fenv_test.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib/msun/tests/fenv_test.c b/lib/msun/tests/fenv_test.c
index 76998a7cb2d5..f275f0725504 100644
--- a/lib/msun/tests/fenv_test.c
+++ b/lib/msun/tests/fenv_test.c
@@ -392,7 +392,27 @@ ATF_TC_BODY(masking, tc)
 	int except, pass, raise, status;
 	unsigned i;
 
-	ATF_CHECK_EQ(0, (fegetexcept() & ALL_STD_EXCEPT));
+	ATF_REQUIRE_EQ(0, (fegetexcept() & ALL_STD_EXCEPT));
+
+	/*
+	 * Some CPUs, e.g. AArch64 QEMU does not support trapping on FP
+	 * exceptions. In that case the trap enable bits are all RAZ/WI, so
+	 * writing to those bits will be ignored and the the next read will
+	 * return all zeroes for those bits. Skip the test if no floating
+	 * point exceptions are supported and mark it XFAIL if some are missing.
+	 */
+	ATF_REQUIRE_EQ(0, (feenableexcept(FE_ALL_EXCEPT)));
+	except = fegetexcept();
+	if (except == 0) {
+		atf_tc_skip("CPU does not support trapping on floating point "
+		    "exceptions.");
+	} else if ((except & ALL_STD_EXCEPT) != ALL_STD_EXCEPT) {
+		atf_tc_expect_fail("Not all floating point exceptions can be "
+		    "set to trap: %#x vs %#x", except, ALL_STD_EXCEPT);
+	}
+	fedisableexcept(FE_ALL_EXCEPT);
+
+
 	ATF_CHECK_EQ(0, (feenableexcept(FE_INVALID|FE_OVERFLOW) & ALL_STD_EXCEPT));
 	ATF_CHECK_EQ((FE_INVALID | FE_OVERFLOW), (feenableexcept(FE_UNDERFLOW) & ALL_STD_EXCEPT));
 	ATF_CHECK_EQ((FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW), (fedisableexcept(FE_OVERFLOW) & ALL_STD_EXCEPT));