math: Use wordsize-64 version for isnan

  - math.h will use compiler builtin for gcc 4.4 when built without
    -fsignaling-nans and the builtin is expanded inline for all
    support architectures.  As an example, there is no intra isnan
    call on libm for the architecture I checked, x86, arm, aarch64,
    and powerpc.

  - The resulting binary difference on 32 bits architecture is minimum
    for the non hotspot symbol.

  - It helps wordsize-64 architectures that use ldbl-opt.

  - It add some code simplification with reduction of duplicated
    implementations.

Checked on powerpc-linux-gnu (built without --with-cpu, with
--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch),
powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+
and --disable-multi-arch).

	* sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c: Move to ...
	* sysdeps/ieee754/dbl-64/s_isnan.c: ... here and format code.

Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>

3 files changed, 9 insertions, 51 deletions

diff --git a/ChangeLog b/ChangeLog
index 59a6484296..d020bb9920 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2019-06-12  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+	* sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c: Move to ...
+	* sysdeps/ieee754/dbl-64/s_isnan.c: ... here and format code.
+
 	* benchtests/Makefile (bench-math): Add isnan, isinf, and isfinite.
 	(CFLAGS-bench-isnan.c, CFLAGS-bench-isinf.c,
 	CFLAGS-bench-isfinite.c): New rule.
diff --git a/sysdeps/ieee754/dbl-64/s_isnan.c b/sysdeps/ieee754/dbl-64/s_isnan.c
index 82723eeb8a..1f1535dea3 100644
--- a/sysdeps/ieee754/dbl-64/s_isnan.c
+++ b/sysdeps/ieee754/dbl-64/s_isnan.c
@@ -10,10 +10,6 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_isnan.c,v 1.8 1995/05/10 20:47:36 jtc Exp $";
-#endif
-
 /*
  * isnan(x) returns 1 is x is nan, else 0;
  * no branching!
@@ -23,17 +19,16 @@ static char rcsid[] = "$NetBSD: s_isnan.c,v 1.8 1995/05/10 20:47:36 jtc Exp $";
 #include <math_private.h>
 #include <ldbl-classify-compat.h>
 #include <shlib-compat.h>
+#include <stdint.h>
 
-#undef __isnan
 int
 __isnan (double x)
 {
-  int32_t hx, lx;
-  EXTRACT_WORDS (hx, lx, x);
-  hx &= 0x7fffffff;
-  hx |= (uint32_t) (lx | (-lx)) >> 31;
-  hx = 0x7ff00000 - hx;
-  return (int) (((uint32_t) hx) >> 31);
+  int64_t hx;
+  EXTRACT_WORDS64 (hx, x);
+  hx &= UINT64_C (0x7fffffffffffffff);
+  hx = UINT64_C (0x7ff0000000000000) - hx;
+  return (int)(((uint64_t)hx)>>63);
 }
 hidden_def (__isnan)
 weak_alias (__isnan, isnan)
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c
deleted file mode 100644
index cd805d157b..0000000000
--- a/sysdeps/ieee754/dbl-64/wordsize-64/s_isnan.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/* @(#)s_isnan.c 5.1 93/09/24 */
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunPro, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
- */
-
-/*
- * isnan(x) returns 1 is x is nan, else 0;
- * no branching!
- */
-
-#include <math.h>
-#include <math_private.h>
-#include <ldbl-classify-compat.h>
-#include <shlib-compat.h>
-#include <stdint.h>
-
-#undef __isnan
-int __isnan(double x)
-{
-	int64_t hx;
-	EXTRACT_WORDS64(hx,x);
-	hx &= UINT64_C(0x7fffffffffffffff);
-	hx = UINT64_C(0x7ff0000000000000) - hx;
-	return (int)(((uint64_t)hx)>>63);
-}
-hidden_def (__isnan)
-weak_alias (__isnan, isnan)
-#ifdef NO_LONG_DOUBLE
-# if LDBL_CLASSIFY_COMPAT && SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
-compat_symbol (libc, __isnan, __isnanl, GLIBC_2_0);
-# endif
-weak_alias (__isnan, isnanl)
-#endif