Re: Clang as default compiler November 4th

On Thu, Sep 13, 2012 at 09:32:12AM -0600, Ian Lepore wrote:
> On Wed, 2012-09-12 at 19:08 -0700, Steve Kargl wrote:
> > In regards to my initial post in this thread, I was just trying
> > to assess whether any benchmarks have been performed on FreeBSD
> > for floating point generated by clang.  Other than the limited
> > testing that I've done, it appears that the answer is 'no'.
> > 
> 
> We have src/tools/tests/testfloat and src/tools/regression/lib/msun.  I
> know nothing about the former (just noticed it for the first time).  The
> latter I think is a set of correctness tests rather than performance
> tests.

It's quite clear that the clang proponent have not tried
to run src/tools/regression/lib/msun.

% setenv CC clang
% make  |& grep warning | wc -l
    1354
% make clean
% make |& tee make.log
% head -20 make.log
clang -O2 -pipe -march=opteron -O0 -lm  test-cexp.c  -o test-cexp
test-cexp.c:49:14: warning: pragma STDC FENV_ACCESS ON is not supported, ignoring pragma [-Wunknown-pragmas]
#pragma STDC FENV_ACCESS        ON
             ^
test-cexp.c:183:2: warning: expression result unused [-Wunused-value]
        testall(0.0, 1.0, ALL_STD_EXCEPT, 0, 1);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test-cexp.c:98:7: note: expanded from macro 'testall'
        test(cexp, x, result, exceptmask, excepts, checksign);          \
             ^
test-cexp.c:87:11: note: expanded from macro 'test'
        assert(((func), fetestexcept(exceptmask) == (excepts)));        \
                 ^
/usr/include/assert.h:54:21: note: expanded from macro 'assert'
#define assert(e)       ((e) ? (void)0 : __assert(__func__, __FILE__, \
                          ^
test-cexp.c:183:2: warning: expression result unused [-Wunused-value]
        testall(0.0, 1.0, ALL_STD_EXCEPT, 0, 1);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test-cexp.c:99:7: note: expanded from macro 'testall'

% tail -20 make.log
test-trig.c:69:11: note: expanded from macro 'test'
        assert(((func), fetestexcept(exceptmask) == (excepts)));        \
                 ^
/usr/include/assert.h:54:21: note: expanded from macro 'assert'
#define assert(e)       ((e) ? (void)0 : __assert(__func__, __FILE__, \
                          ^
74 warnings generated.
clang -O2 -pipe -march=opteron -O0 -lm  test-fenv.c  -o test-fenv
test-fenv.c:82:14: warning: pragma STDC FENV_ACCESS ON is not supported, ignoring pragma [-Wunknown-pragmas]
#pragma STDC FENV_ACCESS ON
             ^
1 warning generated.
for p in test-cexp test-conj test-csqrt test-ctrig  test-exponential test-fma  test-fmaxmin test-ilogb test-invtrig test-logarithm test-lrint  test-lround test-nan test-nearbyint test-next test-rem test-trig  test-fenv; do /usr/src/tools/regression/lib/msun/$p; done
Assertion failed: (((cexp), fetestexcept((0x04 | 0x20 | 0x01 | 0x08 | 0x10)) == (0))), function test_nan, file test-cexp.c, line 211.
1..7
ok 1 - cexp zero
Abort trap (core dumped)
*** [tests] Error code 134

Stop in /usr/src/tools/regression/lib/msun.


So, clang does not support "#pragma STDC FENV_ACCESS ON".
That (IMHO) is a show stopper for clang as the default compiler,
because at least msun/src/e_sqrtl.c uses this pragma.

-- 
Steve