Teach SDISel to combine fsin / fcos into a fsincos node if the following
conditions are met:
1. They share the same operand and are in the same BB.
2. Both outputs are used.
3. The target has a native instruction that maps to ISD::FSINCOS node or
   the target provides a sincos library call.

Implemented the generic optimization in sdisel and enabled it for
Mac OSX. Also added an additional optimization for x86_64 Mac OSX by
using an alternative entry point __sincos_stret which returns the two
results in xmm0 / xmm1.

rdar://13087969
PR13204


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173755 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index 53c28f4..dad95c6 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -155,6 +155,11 @@
   return 0;
 }
 
+bool X86Subtarget::hasSinCos() const {
+  return getTargetTriple().isMacOSX() &&
+    !getTargetTriple().isMacOSXVersionLT(10, 9);
+}
+
 /// IsLegalToCallImmediateAddr - Return true if the subtarget allows calls
 /// to immediate address.
 bool X86Subtarget::IsLegalToCallImmediateAddr(const TargetMachine &TM) const {