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[COMMITTED,3/4] alpha: Implement math_opt_barrier and math_force_eval

Message ID 1404410446-30243-3-git-send-email-rth@twiddle.net
State New
Headers show

Commit Message

Richard Henderson July 3, 2014, 6 p.m. UTC 
We need not force values to memory like i387.
---
 ChangeLog                        | 3 +++
 sysdeps/alpha/fpu/math_private.h | 6 ++++++
 2 files changed, 9 insertions(+)
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Patch

diff --git a/ChangeLog b/ChangeLog
index 017003e..e84fbbf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@ 
 2014-07-03  Richard Henderson  <rth@redhat.com>
 
+	* sysdeps/alpha/fpu/math_private.h (math_opt_barrier): New.
+	(math_force_eval): New.
+
 	* sysdeps/alpha/fpu/s_lround.c: Add 0.5 with chopped rounding.
 	* sysdeps/alpha/fpu/s_lroundf.c: Likewise.
 
diff --git a/sysdeps/alpha/fpu/math_private.h b/sysdeps/alpha/fpu/math_private.h
index 22ab3b9..9e06e25 100644
--- a/sysdeps/alpha/fpu/math_private.h
+++ b/sysdeps/alpha/fpu/math_private.h
@@ -13,6 +13,12 @@ 
 # define __isnanf __isnanf
 #endif
 
+/* Generic code forces values to memory; we don't need to do that.  */
+#define math_opt_barrier(x) \
+  ({ __typeof (x) __x = (x); __asm ("" : "+frm" (__x)); __x; })
+#define math_force_eval(x) \
+  ({ __typeof (x) __x = (x); __asm __volatile__ ("" : : "frm" (__x)); })
+
 #include_next <math_private.h>
 
 #ifdef __alpha_fix__