Add x86 optimization of rint functions and tests

Change-Id: I5e7696ff9bcb1efc2625100ef8565b68dca2326c
Signed-off-by: Jingwei Zhang <jingwei.zhang@intel.com>
diff --git a/libm/x86/lrintf.S b/libm/x86/lrintf.S
new file mode 100644
index 0000000..bc8fcb3
--- /dev/null
+++ b/libm/x86/lrintf.S
@@ -0,0 +1,33 @@
+/*
+Copyright (c) 2014, Intel Corporation
+All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright notice,
+    * this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright notice,
+    * this list of conditions and the following disclaimer in the documentation
+    * and/or other materials provided with the distribution.
+    * Neither the name of Intel Corporation nor the names of its contributors
+    * may be used to endorse or promote products derived from this software
+    * without specific prior written permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <private/bionic_asm.h>
+
+ENTRY(lrintf)
+  // LP32 sizeof(long) == 4.
+  movss     0x4(%esp),%xmm0
+  cvtss2si  %xmm0, %eax
+  ret
+END(lrintf)