Use compiler builtins for fabs.

Change-Id: Id3bf761d6dfc187f218b5215c53d76bddc83d50b

benchmarks/math_benchmark.cpp

@@ -258,3 +258,29 @@ void BM_math_signbit::Run(int iters, double value) {
 
   StopBenchmarkTiming();
 }
+
+BENCHMARK_WITH_ARG(BM_math_fabs_macro, double)->AT_COMMON_VALS;
+void BM_math_fabs_macro::Run(int iters, double value) {
+  StartBenchmarkTiming();
+
+  d = 0.0;
+  v = value;
+  for (int i = 0; i < iters; ++i) {
+    d += fabs(v);
+  }
+
+  StopBenchmarkTiming();
+}
+
+BENCHMARK_WITH_ARG(BM_math_fabs, double)->AT_COMMON_VALS;
+void BM_math_fabs::Run(int iters, double value) {
+  StartBenchmarkTiming();
+
+  d = 0.0;
+  v = value;
+  for (int i = 0; i < iters; ++i) {
+    d += (fabs)(v);
+  }
+
+  StopBenchmarkTiming();
+}

libm/Android.mk

@@ -108,8 +108,6 @@ LOCAL_SRC_FILES := \
     upstream-freebsd/lib/msun/src/s_exp2.c \
     upstream-freebsd/lib/msun/src/s_exp2f.c \
     upstream-freebsd/lib/msun/src/s_expm1f.c \
-    upstream-freebsd/lib/msun/src/s_fabs.c \
-    upstream-freebsd/lib/msun/src/s_fabsf.c \
     upstream-freebsd/lib/msun/src/s_fdim.c \
     upstream-freebsd/lib/msun/src/s_finite.c \
     upstream-freebsd/lib/msun/src/s_finitef.c \
@@ -175,7 +173,6 @@ LOCAL_SRC_FILES_64 := \
     upstream-freebsd/lib/msun/src/s_copysignl.c \
     upstream-freebsd/lib/msun/src/e_coshl.c \
     upstream-freebsd/lib/msun/src/s_cosl.c \
-    upstream-freebsd/lib/msun/src/s_fabsl.c \
     upstream-freebsd/lib/msun/src/s_floorl.c \
     upstream-freebsd/lib/msun/src/s_fmal.c \
     upstream-freebsd/lib/msun/src/s_fmaxl.c \
@@ -228,6 +225,10 @@ LOCAL_SRC_FILES += \
 LOCAL_SRC_FILES += \
     signbit.c \
 
+# Home-grown stuff.
+LOCAL_SRC_FILES += \
+    fabs.cpp \
+
 # Arch specific optimizations.
 
 # -----------------------------------------------------------------------------

libm/fabs.cpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <math.h>
+
+#include "fpmath.h"
+
+double fabs(double x) {
+#if __arm__
+  // Both Clang and GCC insist on moving r0/r1 into a double register
+  // and using fabs where bit-twiddling would be a better choice.
+  // They get fabsf right, but we need to be careful in fabsl too.
+  IEEEd2bits u;
+  u.d = x;
+  u.bits.sign = 0;
+  return u.d;
+#else
+  return __builtin_fabs(x);
+#endif
+}
+
+float fabsf(float x) {
+  return __builtin_fabsf(x);
+}
+
+#if defined(__LP64__)
+long double fabsl(long double x) { return __builtin_fabsl(x); }
+#else
+long double fabsl(long double x) {
+  // Don't use __builtin_fabs here because of ARM. (See fabs above.)
+  return fabs(x);
+}
+#endif

libm/fake_long_double.c

@@ -25,7 +25,6 @@
  */
 
 long double copysignl(long double a1, long double a2) { return copysign(a1, a2); }
-long double fabsl(long double a1) { return fabs(a1); }
 long double fmaxl(long double a1, long double a2) { return fmax(a1, a2); }
 long double fmodl(long double a1, long double a2) { return fmod(a1, a2); }
 long double fminl(long double a1, long double a2) { return fmin(a1, a2); }

libm/include/math.h

@@ -20,6 +20,8 @@
 #include <sys/cdefs.h>
 #include <limits.h>
 
+#define __BIONIC_MATH_INLINE extern __inline__ __always_inline __attribute__((gnu_inline)) __attribute__((__artificial__))
+
 __BEGIN_DECLS
 #pragma GCC visibility push(default)
 
@@ -161,6 +163,7 @@ double	sqrt(double);
 
 double	ceil(double);
 double	fabs(double) __pure2;
+__BIONIC_MATH_INLINE double fabs(double x) { return __builtin_fabs(x); }
 double	floor(double);
 double	fmod(double, double);
 
@@ -279,6 +282,7 @@ float	sqrtf(float);
 
 float	ceilf(float);
 float	fabsf(float) __pure2;
+__BIONIC_MATH_INLINE float fabsf(float x) { return __builtin_fabsf(x); }
 float	floorf(float);
 float	fmodf(float, float);
 float	roundf(float);
@@ -366,6 +370,7 @@ long double	exp2l(long double);
 long double	expl(long double);
 long double	expm1l(long double);
 long double	fabsl(long double) __pure2;
+__BIONIC_MATH_INLINE long double fabsl(long double x) { return __builtin_fabsl(x); }
 long double	fdiml(long double, long double);
 long double	floorl(long double);
 long double	fmal(long double, long double, long double);

libm/upstream-freebsd/lib/msun/src/s_fabs.c

@@ -1,31 +0,0 @@
-/* @(#)s_fabs.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.
- * ====================================================
- */
-
-#ifndef lint
-static char rcsid[] = "$FreeBSD$";
-#endif
-
-/*
- * fabs(x) returns the absolute value of x.
- */
-
-#include "math.h"
-#include "math_private.h"
-
-double
-fabs(double x)
-{
-	u_int32_t high;
-	GET_HIGH_WORD(high,x);
-	SET_HIGH_WORD(x,high&0x7fffffff);
-        return x;
-}

libm/upstream-freebsd/lib/msun/src/s_fabsf.c

@@ -1,33 +0,0 @@
-/* s_fabsf.c -- float version of s_fabs.c.
- * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
- */
-
-/*
- * ====================================================
- * 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.
- * ====================================================
- */
-
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-/*
- * fabsf(x) returns the absolute value of x.
- */
-
-#include "math.h"
-#include "math_private.h"
-
-float
-fabsf(float x)
-{
-	u_int32_t ix;
-	GET_FLOAT_WORD(ix,x);
-	SET_FLOAT_WORD(x,ix&0x7fffffff);
-        return x;
-}