Fix an assertion failure in isMacOSXVersionLT for IOS targets.

Check if the triple OS is IOS instead of checking for arm/thumb architectures
and check that before calling isMacOSXVersionLT.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149454 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp b/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
index 6c800a2..68c578e 100644
--- a/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/CallAndMessageChecker.cpp
@@ -286,10 +286,9 @@
 }
 
 static bool supportsNilWithFloatRet(const llvm::Triple &triple) {
-  return triple.getVendor() == llvm::Triple::Apple &&
-         (!triple.isMacOSXVersionLT(10,5) ||
-          triple.getArch() == llvm::Triple::arm || 
-          triple.getArch() == llvm::Triple::thumb);
+  return (triple.getVendor() == llvm::Triple::Apple &&
+          (triple.getOS() == llvm::Triple::IOS ||
+           !triple.isMacOSXVersionLT(10,5)));
 }
 
 void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C,