Enable optimization of sin / cos pair into call to __sincos_stret for iOS7+.

rdar://12856873
Patch by Evan Cheng, with a fix for rdar://13209539 by Tilmann Scheller

llvm-svn: 193942
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index 392b6f5..f59e522 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -281,6 +281,11 @@
   return SchedModel->MispredictPenalty;
 }
 
+bool ARMSubtarget::hasSinCos() const {
+  return getTargetTriple().getOS() == Triple::IOS &&
+    !getTargetTriple().isOSVersionLT(7, 0);
+}
+
 bool ARMSubtarget::enablePostRAScheduler(
            CodeGenOpt::Level OptLevel,
            TargetSubtargetInfo::AntiDepBreakMode& Mode,