These tests check whether the compiler evaluates floating-point

expressions properly.  Some of the tests depend on the compiler
implementing C99's FENV_ACCESS pragma, and only commercial compilers
do; those tests are currently skipped.  If any of the enabled tests
fail, then odds are the libm regression tests will fail also.
This should make it easier to diagnose reported problems on platforms
I don't have.

Currently, gcc passes all the tests that don't depend on FENV_ACCESS
on amd64 and sparc64.  Clang fails a few on amd64 (see clang bug
11406).  Both gcc and clang fare poorly on i386, which has well-known
issues.
This commit is contained in:
David Schultz 2012-01-20 06:57:21 +00:00
parent 7082a2cf72
commit b831cdf6b1
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=230368
3 changed files with 293 additions and 0 deletions

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# $FreeBSD$
TESTS= float
CFLAGS+=-lm
.PHONY: tests
tests: ${TESTS}
for p in ${TESTS}; do ${.OBJDIR}/$$p; done
.PHONY: clean
clean:
-rm -f ${TESTS}

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/*-
* Copyright (c) 2012 David Schultz <das@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Test that floating-point arithmetic works as specified by the C standard.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <fenv.h>
#include <float.h>
#include <math.h>
#include <stdio.h>
#ifdef __i386__
#include <ieeefp.h>
#endif
#define ALL_STD_EXCEPT (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \
FE_OVERFLOW | FE_UNDERFLOW)
#define TWICE(x) ((x) + (x))
#define test(desc, pass) test1((desc), (pass), 0)
#define skiptest(desc, pass) test1((desc), (pass), 1)
#pragma STDC FENV_ACCESS ON
static const float one_f = 1.0 + FLT_EPSILON / 2;
static const double one_d = 1.0 + DBL_EPSILON / 2;
static const long double one_ld = 1.0L + LDBL_EPSILON / 2;
static int testnum, failures;
static void
test1(const char *testdesc, int pass, int skip)
{
testnum++;
printf("%sok %d - %s%s\n", pass || skip ? "" : "not ", testnum,
skip ? "(SKIPPED) " : "", testdesc);
if (!pass && !skip)
failures++;
}
/*
* Compare d1 and d2 using special rules: NaN == NaN and +0 != -0.
*/
static int
fpequal(long double d1, long double d2)
{
if (d1 != d2)
return (isnan(d1) && isnan(d2));
return (copysignl(1.0, d1) == copysignl(1.0, d2));
}
void
run_zero_opt_test(double d1, double d2)
{
test("optimizations don't break the sign of 0",
fpequal(d1 - d2, 0.0)
&& fpequal(-d1 + 0.0, 0.0)
&& fpequal(-d1 - d2, -0.0)
&& fpequal(-(d1 - d2), -0.0)
&& fpequal(-d1 - (-d2), 0.0));
}
void
run_inf_opt_test(double d)
{
test("optimizations don't break infinities",
fpequal(d / d, NAN) && fpequal(0.0 * d, NAN));
}
static inline double
todouble(long double ld)
{
return (ld);
}
static inline float
tofloat(double d)
{
return (d);
}
void
run_tests(void)
{
volatile long double vld;
long double ld;
volatile double vd;
double d;
volatile float vf;
float f;
int x;
test("sign bits", fpequal(-0.0, -0.0) && !fpequal(0.0, -0.0));
vd = NAN;
test("NaN equality", fpequal(NAN, NAN) && NAN != NAN && vd != vd);
feclearexcept(ALL_STD_EXCEPT);
test("NaN comparison returns false", !(vd <= vd));
/*
* XXX disabled; gcc/amd64 botches this IEEE 754 requirement by
* emitting ucomisd instead of comisd.
*/
skiptest("FENV_ACCESS: NaN comparison raises invalid exception",
fetestexcept(ALL_STD_EXCEPT) == FE_INVALID);
vd = 0.0;
run_zero_opt_test(vd, vd);
vd = INFINITY;
run_inf_opt_test(vd);
feclearexcept(ALL_STD_EXCEPT);
vd = INFINITY;
x = (int)vd;
/* XXX disabled (works with -O0); gcc doesn't support FENV_ACCESS */
skiptest("FENV_ACCESS: Inf->int conversion raises invalid exception",
fetestexcept(ALL_STD_EXCEPT) == FE_INVALID);
/* Raising an inexact exception here is an IEEE-854 requirement. */
feclearexcept(ALL_STD_EXCEPT);
vd = 0.75;
x = (int)vd;
test("0.75->int conversion rounds toward 0, raises inexact exception",
x == 0 && fetestexcept(ALL_STD_EXCEPT) == FE_INEXACT);
feclearexcept(ALL_STD_EXCEPT);
vd = -42.0;
x = (int)vd;
test("-42.0->int conversion is exact, raises no exception",
x == -42 && fetestexcept(ALL_STD_EXCEPT) == 0);
feclearexcept(ALL_STD_EXCEPT);
x = (int)INFINITY;
/* XXX disabled; gcc doesn't support FENV_ACCESS */
skiptest("FENV_ACCESS: const Inf->int conversion raises invalid",
fetestexcept(ALL_STD_EXCEPT) == FE_INVALID);
feclearexcept(ALL_STD_EXCEPT);
x = (int)0.5;
/* XXX disabled; gcc doesn't support FENV_ACCESS */
skiptest("FENV_ACCESS: const double->int conversion raises inexact",
x == 0 && fetestexcept(ALL_STD_EXCEPT) == FE_INEXACT);
test("compile-time constants don't have too much precision",
one_f == 1.0L && one_d == 1.0L && one_ld == 1.0L);
test("const minimum rounding precision",
1.0F + FLT_EPSILON != 1.0F &&
1.0 + DBL_EPSILON != 1.0 &&
1.0L + LDBL_EPSILON != 1.0L);
/* It isn't the compiler's fault if this fails on FreeBSD/i386. */
vf = FLT_EPSILON;
vd = DBL_EPSILON;
vld = LDBL_EPSILON;
test("runtime minimum rounding precision",
1.0F + vf != 1.0F && 1.0 + vd != 1.0 && 1.0L + vld != 1.0L);
test("explicit float to float conversion discards extra precision",
(float)(1.0F + FLT_EPSILON * 0.5F) == 1.0F &&
(float)(1.0F + vf * 0.5F) == 1.0F);
test("explicit double to float conversion discards extra precision",
(float)(1.0 + FLT_EPSILON * 0.5) == 1.0F &&
(float)(1.0 + vf * 0.5) == 1.0F);
test("explicit ldouble to float conversion discards extra precision",
(float)(1.0L + FLT_EPSILON * 0.5L) == 1.0F &&
(float)(1.0L + vf * 0.5L) == 1.0F);
test("explicit double to double conversion discards extra precision",
(double)(1.0 + DBL_EPSILON * 0.5) == 1.0 &&
(double)(1.0 + vd * 0.5) == 1.0);
test("explicit ldouble to double conversion discards extra precision",
(double)(1.0L + DBL_EPSILON * 0.5L) == 1.0 &&
(double)(1.0L + vd * 0.5L) == 1.0);
/*
* FLT_EVAL_METHOD > 1 implies that float expressions are always
* evaluated in double precision or higher, but some compilers get
* this wrong when registers spill to memory. The following expression
* forces a spill when there are at most 8 FP registers.
*/
test("implicit promption to double or higher precision is consistent",
#if FLT_EVAL_METHOD == 1 || FLT_EVAL_METHOD == 2 || defined(__i386__)
TWICE(TWICE(TWICE(TWICE(TWICE(
TWICE(TWICE(TWICE(TWICE(1.0F + vf * 0.5F)))))))))
== (1.0 + FLT_EPSILON * 0.5) * 512.0
#else
1
#endif
);
f = 1.0 + FLT_EPSILON * 0.5;
d = 1.0L + DBL_EPSILON * 0.5L;
test("const assignment discards extra precision", f == 1.0F && d == 1.0);
f = 1.0 + vf * 0.5;
d = 1.0L + vd * 0.5L;
test("variable assignment discards explicit extra precision",
f == 1.0F && d == 1.0);
f = 1.0F + vf * 0.5F;
d = 1.0 + vd * 0.5;
test("variable assignment discards implicit extra precision",
f == 1.0F && d == 1.0);
test("return discards extra precision",
tofloat(1.0 + vf * 0.5) == 1.0F &&
todouble(1.0L + vd * 0.5L) == 1.0);
fesetround(FE_UPWARD);
/* XXX disabled (works with -frounding-math) */
skiptest("FENV_ACCESS: constant arithmetic respects rounding mode",
1.0F + FLT_MIN == 1.0F + FLT_EPSILON &&
1.0 + DBL_MIN == 1.0 + DBL_EPSILON &&
1.0L + LDBL_MIN == 1.0L + LDBL_EPSILON);
fesetround(FE_TONEAREST);
ld = vld * 0.5;
test("associativity is respected",
1.0L + ld + (LDBL_EPSILON * 0.5) == 1.0L &&
1.0L + (LDBL_EPSILON * 0.5) + ld == 1.0L &&
ld + 1.0 + (LDBL_EPSILON * 0.5) == 1.0L &&
ld + (LDBL_EPSILON * 0.5) + 1.0 == 1.0L + LDBL_EPSILON);
}
int
main(int argc, char *argv[])
{
printf("1..26\n");
#ifdef __i386__
fpsetprec(FP_PE);
#endif
run_tests();
return (failures);
}

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#!/bin/sh
# $FreeBSD$
cd `dirname $0`
executable=`basename $0 .t`
make $executable 2>&1 > /dev/null
exec ./$executable