Date: Thu, 13 Sep 2012 09:10:24 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Ian Lepore <freebsd@damnhippie.dyndns.org> Cc: toolchain@freebsd.org, Tijl Coosemans <tijl@coosemans.org>, Dimitry Andric <dim@freebsd.org>, Nathan Whitehorn <nwhitehorn@freebsd.org>, current@freebsd.org Subject: Re: Clang as default compiler November 4th Message-ID: <20120913161024.GA13846@troutmask.apl.washington.edu> In-Reply-To: <1347550332.1110.108.camel@revolution.hippie.lan> References: <20120910211207.GC64920@lor.one-eyed-alien.net> <20120911104518.GF37286@deviant.kiev.zoral.com.ua> <20120911120649.GA52235@freebsd.org> <20120911132410.GA87126@troutmask.apl.washington.edu> <504F4645.4070900@FreeBSD.org> <504F4A6B.4010001@coosemans.org> <504F5101.8090906@FreeBSD.org> <505101C3.70203@freebsd.org> <20120913020833.GA8255@troutmask.apl.washington.edu> <1347550332.1110.108.camel@revolution.hippie.lan>
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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
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