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authorAurelien Jarno <aurelien@aurel32.net>2016-08-02 09:18:59 +0200
committerMike Frysinger <vapier@gentoo.org>2016-12-08 00:38:41 -0500
commitb099b9c11b003927010b18fe7adf66b5f1c1817c (patch)
tree92300c6afd897492aa1b4f908fb726ae30ed53d2
parent201fca8584b5aca30e807890b607064f16ef38ef (diff)
downloadglibc-gentoo/2.23.tar.gz
glibc-gentoo/2.23.tar.xz
glibc-gentoo/2.23.zip
alpha: fix trunc for big input values gentoo/2.23
The alpha specific version of trunc and truncf always add and subtract
0x1.0p23 or 0x1.0p52 even for big values. This causes this kind of
errors in the testsuite:

  Failure: Test: trunc_towardzero (0x1p107)
  Result:
   is:          1.6225927682921334e+32   0x1.fffffffffffffp+106
   should be:   1.6225927682921336e+32   0x1.0000000000000p+107
   difference:  1.8014398509481984e+16   0x1.0000000000000p+54
   ulp       :  0.5000
   max.ulp   :  0.0000

Change this by returning the input value when its absolute value is
greater than 0x1.0p23 or 0x1.0p52. NaN have to go through the add and
subtract operations to get possibly silenced.

Finally remove the code to handle inexact exception, trunc should never
generate such an exception.

Changelog:
	* sysdeps/alpha/fpu/s_trunc.c (__trunc): Return the input value
	when its absolute value is greater than 0x1.0p52.
	[_IEEE_FP_INEXACT] Remove.
	* sysdeps/alpha/fpu/s_truncf.c (__truncf): Return the input value
	when its absolute value is greater than 0x1.0p23.
	[_IEEE_FP_INEXACT] Remove.

(cherry picked from commit b74d259fe793499134eb743222cd8dd7c74a31ce)
(cherry picked from commit 3a5aa2ee4ffc515c8e7e615ea38d6b3b20ed0a30)
-rw-r--r--sysdeps/alpha/fpu/s_trunc.c7
-rw-r--r--sysdeps/alpha/fpu/s_truncf.c7
2 files changed, 6 insertions, 8 deletions
diff --git a/sysdeps/alpha/fpu/s_trunc.c b/sysdeps/alpha/fpu/s_trunc.c
index 16cb114a72..4b986a6926 100644
--- a/sysdeps/alpha/fpu/s_trunc.c
+++ b/sysdeps/alpha/fpu/s_trunc.c
@@ -28,12 +28,11 @@ __trunc (double x)
   double two52 = copysign (0x1.0p52, x);
   double r, tmp;
 
+  if (isgreaterequal (fabs (x), 0x1.0p52))
+    return x;
+
   __asm (
-#ifdef _IEEE_FP_INEXACT
-	 "addt/suic %2, %3, %1\n\tsubt/suic %1, %3, %0"
-#else
 	 "addt/suc %2, %3, %1\n\tsubt/suc %1, %3, %0"
-#endif
 	 : "=&f"(r), "=&f"(tmp)
 	 : "f"(x), "f"(two52));
 
diff --git a/sysdeps/alpha/fpu/s_truncf.c b/sysdeps/alpha/fpu/s_truncf.c
index 2290f28295..3e93356166 100644
--- a/sysdeps/alpha/fpu/s_truncf.c
+++ b/sysdeps/alpha/fpu/s_truncf.c
@@ -27,12 +27,11 @@ __truncf (float x)
   float two23 = copysignf (0x1.0p23, x);
   float r, tmp;
 
+  if (isgreaterequal (fabsf (x), 0x1.0p23))
+    return x;
+
   __asm (
-#ifdef _IEEE_FP_INEXACT
-	 "adds/suic %2, %3, %1\n\tsubs/suic %1, %3, %0"
-#else
 	 "adds/suc %2, %3, %1\n\tsubs/suc %1, %3, %0"
-#endif
 	 : "=&f"(r), "=&f"(tmp)
 	 : "f"(x), "f"(two23));