Use builtins for fma/fmax/fmin/round on arm/arm64.

Bug: http://b/27829506
Test: ran tests and inspected arm/arm64/x86/x86-64 assembler
Change-Id: I8af60b44c75dddbb11949f208a8a70ed3cff12c8

1 files changed, 60 insertions, 0 deletions

diff --git a/libm/builtins.cpp b/libm/builtins.cpp
new file mode 100644
index 000000000..aec0f5fa0
--- /dev/null
+++ b/libm/builtins.cpp
@@ -0,0 +1,60 @@
+/*
+ * 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
+
+#if defined(__arm__) || defined(__aarch64__)
+float fmaf(float x, float y, float z) { return __builtin_fmaf(x, y, z); }
+double fma(double x, double y, double z) { return __builtin_fma(x, y, z); }
+
+float fmaxf(float x, float y) { return __builtin_fmaxf(x, y); }
+double fmax(double x, double y) { return __builtin_fmax(x, y); }
+
+float fminf(float x, float y) { return __builtin_fminf(x, y); }
+double fmin(double x, double y) { return __builtin_fmin(x, y); }
+
+float roundf(float x) { return __builtin_roundf(x); }
+double round(double x) { return __builtin_round(x); }
+#endif