diff mbox

[v3] force eval for fma implementations

Message ID 1406915515-18596-1-git-send-email-rth@twiddle.net
State New
Headers show

Commit Message

Richard Henderson Aug. 1, 2014, 5:51 p.m. UTC 
Now with corresponding fixes to ldbl-96/s_fma.c, ldbl-96/s_fmal.c
and ldbl-128/s_fmal.c, as suggested by Joseph.

Ok?


r~


	* 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.

---
 sysdeps/ieee754/dbl-64/s_fma.c    | 11 ++++++-----
 sysdeps/ieee754/ldbl-128/s_fmal.c | 11 ++++++-----
 sysdeps/ieee754/ldbl-96/s_fma.c   | 11 ++++++-----
 sysdeps/ieee754/ldbl-96/s_fmal.c  | 11 ++++++-----
 4 files changed, 24 insertions(+), 20 deletions(-)

Comments

Joseph Myers Aug. 1, 2014, 9:25 p.m. UTC | #1 
On Fri, 1 Aug 2014, Richard Henderson wrote:

> Now with corresponding fixes to ldbl-96/s_fma.c, ldbl-96/s_fmal.c
> and ldbl-128/s_fmal.c, as suggested by Joseph.
> 
> Ok?

OK.
diff mbox

Patch

diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
index 389acd4..77065aa 100644
--- a/sysdeps/ieee754/dbl-64/s_fma.c
+++ b/sysdeps/ieee754/dbl-64/s_fma.c
@@ -198,16 +198,17 @@  __fma (double x, double y, double z)
   t1 = m1 - t1;
   t2 = z - 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);
 
-  /* If the result is an exact zero, ensure it has the correct
-     sign.  */
+  /* If the result is an exact zero, ensure it has the correct sign.  */
   if (a1 == 0 && m2 == 0)
     {
       libc_feupdateenv (&env);
-      /* Ensure that round-to-nearest value of z + m1 is not
-	 reused.  */
-      asm volatile ("" : "=m" (z) : "m" (z));
+      /* Ensure that round-to-nearest value of z + m1 is not reused.  */
+      z = math_opt_barrier (z);
       return z + m1;
     }
 
diff --git a/sysdeps/ieee754/ldbl-128/s_fmal.c b/sysdeps/ieee754/ldbl-128/s_fmal.c
index 1d5f27b..8147094 100644
--- a/sysdeps/ieee754/ldbl-128/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-128/s_fmal.c
@@ -203,16 +203,17 @@  __fmal (long double x, long double y, long double z)
   t1 = m1 - t1;
   t2 = z - 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);
 
-  /* If the result is an exact zero, ensure it has the correct
-     sign.  */
+  /* If the result is an exact zero, ensure it has the correct sign.  */
   if (a1 == 0 && m2 == 0)
     {
       feupdateenv (&env);
-      /* Ensure that round-to-nearest value of z + m1 is not
-	 reused.  */
-      asm volatile ("" : "=m" (z) : "m" (z));
+      /* Ensure that round-to-nearest value of z + m1 is not reused.  */
+      z = math_opt_barrier (z);
       return z + m1;
     }
 
diff --git a/sysdeps/ieee754/ldbl-96/s_fma.c b/sysdeps/ieee754/ldbl-96/s_fma.c
index 354be4e..a27102e 100644
--- a/sysdeps/ieee754/ldbl-96/s_fma.c
+++ b/sysdeps/ieee754/ldbl-96/s_fma.c
@@ -64,16 +64,17 @@  __fma (double x, double y, double z)
   t1 = m1 - t1;
   t2 = z - 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);
 
-  /* If the result is an exact zero, ensure it has the correct
-     sign.  */
+  /* If the result is an exact zero, ensure it has the correct sign.  */
   if (a1 == 0 && m2 == 0)
     {
       feupdateenv (&env);
-      /* Ensure that round-to-nearest value of z + m1 is not
-	 reused.  */
-      asm volatile ("" : "=m" (z) : "m" (z));
+      /* Ensure that round-to-nearest value of z + m1 is not reused.  */
+      z = math_opt_barrier (z);
       return z + m1;
     }
 
diff --git a/sysdeps/ieee754/ldbl-96/s_fmal.c b/sysdeps/ieee754/ldbl-96/s_fmal.c
index 4983eda..0f299da 100644
--- a/sysdeps/ieee754/ldbl-96/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-96/s_fmal.c
@@ -201,16 +201,17 @@  __fmal (long double x, long double y, long double z)
   t1 = m1 - t1;
   t2 = z - 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);
 
-  /* If the result is an exact zero, ensure it has the correct
-     sign.  */
+  /* If the result is an exact zero, ensure it has the correct sign.  */
   if (a1 == 0 && m2 == 0)
     {
       feupdateenv (&env);
-      /* Ensure that round-to-nearest value of z + m1 is not
-	 reused.  */
-      asm volatile ("" : "=m" (z) : "m" (z));
+      /* Ensure that round-to-nearest value of z + m1 is not reused.  */
+      z = math_opt_barrier (z);
       return z + m1;
     }