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Force eval for fma implementations

This commit is contained in:
Richard Henderson 2014-08-01 12:13:50 -10:00
parent 6f64e7d75f
commit 4896f04920
5 changed files with 33 additions and 20 deletions
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9
ChangeLog
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@ -1,3 +1,12 @@
2014-08-01 Richard Henderon <rth@redhat.com>
* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Use math_force_eval before
feclearexcept; use math_opt_barrier instead of open-coded asm; fix
typo in exact zero test.
* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Likewise.
* sysdeps/ieee754/ldbl-96/s_fma.c (__fma): Likewise.
* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Likewise.
2014-08-01 Roland McGrath <roland@hack.frob.com> 2014-08-01 Roland McGrath <roland@hack.frob.com>
* sysdeps/unix/sysv/linux/arm/sysdep.h (PTR_MANGLE_LOAD, PTR_MANGLE) * sysdeps/unix/sysv/linux/arm/sysdep.h (PTR_MANGLE_LOAD, PTR_MANGLE)

11
sysdeps/ieee754/dbl-64/s_fma.c
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@ -198,16 +198,17 @@ __fma (double x, double y, double z)
t1 = m1 - t1; t1 = m1 - t1;
t2 = z - t2; t2 = z - t2;
double a2 = t1 + t2; double a2 = t1 + t2;
/* Ensure the arithmetic is not scheduled after feclearexcept call. */
math_force_eval (m2);
math_force_eval (a2);
feclearexcept (FE_INEXACT); feclearexcept (FE_INEXACT);
/* If the result is an exact zero, ensure it has the correct /* If the result is an exact zero, ensure it has the correct sign. */
sign. */
if (a1 == 0 && m2 == 0) if (a1 == 0 && m2 == 0)
{ {
libc_feupdateenv (&env); libc_feupdateenv (&env);
/* Ensure that round-to-nearest value of z + m1 is not /* Ensure that round-to-nearest value of z + m1 is not reused. */
reused. */ z = math_opt_barrier (z);
asm volatile ("" : "=m" (z) : "m" (z));
return z + m1; return z + m1;
} }

11
sysdeps/ieee754/ldbl-128/s_fmal.c
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@ -203,16 +203,17 @@ __fmal (long double x, long double y, long double z)
t1 = m1 - t1; t1 = m1 - t1;
t2 = z - t2; t2 = z - t2;
long double a2 = t1 + t2; long double a2 = t1 + t2;
/* Ensure the arithmetic is not scheduled after feclearexcept call. */
math_force_eval (m2);
math_force_eval (a2);
feclearexcept (FE_INEXACT); feclearexcept (FE_INEXACT);
/* If the result is an exact zero, ensure it has the correct /* If the result is an exact zero, ensure it has the correct sign. */
sign. */
if (a1 == 0 && m2 == 0) if (a1 == 0 && m2 == 0)
{ {
feupdateenv (&env); feupdateenv (&env);
/* Ensure that round-to-nearest value of z + m1 is not /* Ensure that round-to-nearest value of z + m1 is not reused. */
reused. */ z = math_opt_barrier (z);
asm volatile ("" : "=m" (z) : "m" (z));
return z + m1; return z + m1;
} }

11
sysdeps/ieee754/ldbl-96/s_fma.c
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@ -64,16 +64,17 @@ __fma (double x, double y, double z)
t1 = m1 - t1; t1 = m1 - t1;
t2 = z - t2; t2 = z - t2;
long double a2 = t1 + t2; long double a2 = t1 + t2;
/* Ensure the arithmetic is not scheduled after feclearexcept call. */
math_force_eval (m2);
math_force_eval (a2);
feclearexcept (FE_INEXACT); feclearexcept (FE_INEXACT);
/* If the result is an exact zero, ensure it has the correct /* If the result is an exact zero, ensure it has the correct sign. */
sign. */
if (a1 == 0 && m2 == 0) if (a1 == 0 && m2 == 0)
{ {
feupdateenv (&env); feupdateenv (&env);
/* Ensure that round-to-nearest value of z + m1 is not /* Ensure that round-to-nearest value of z + m1 is not reused. */
reused. */ z = math_opt_barrier (z);
asm volatile ("" : "=m" (z) : "m" (z));
return z + m1; return z + m1;
} }

11
sysdeps/ieee754/ldbl-96/s_fmal.c
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@ -201,16 +201,17 @@ __fmal (long double x, long double y, long double z)
t1 = m1 - t1; t1 = m1 - t1;
t2 = z - t2; t2 = z - t2;
long double a2 = t1 + t2; long double a2 = t1 + t2;
/* Ensure the arithmetic is not scheduled after feclearexcept call. */
math_force_eval (m2);
math_force_eval (a2);
feclearexcept (FE_INEXACT); feclearexcept (FE_INEXACT);
/* If the result is an exact zero, ensure it has the correct /* If the result is an exact zero, ensure it has the correct sign. */
sign. */
if (a1 == 0 && m2 == 0) if (a1 == 0 && m2 == 0)
{ {
feupdateenv (&env); feupdateenv (&env);
/* Ensure that round-to-nearest value of z + m1 is not /* Ensure that round-to-nearest value of z + m1 is not reused. */
reused. */ z = math_opt_barrier (z);
asm volatile ("" : "=m" (z) : "m" (z));
return z + m1; return z + m1;
} }