Implement codegen support for lowering "library builtins" like __builtin_isinf 
to their corresponding library routines (e.g. isinf).  This allows us to handle
all the stuff in macos math.h, and other stuff as it's added to *Builtins.def.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@41634 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CGBuiltin.cpp b/CodeGen/CGBuiltin.cpp
index a04557b..03b5c2d 100644
--- a/CodeGen/CGBuiltin.cpp
+++ b/CodeGen/CGBuiltin.cpp
@@ -17,12 +17,16 @@
 #include "clang/AST/Builtins.h"
 #include "clang/AST/Expr.h"
 #include "llvm/Constants.h"
+#include "llvm/Function.h"
 using namespace clang;
 using namespace CodeGen;
 
 RValue CodeGenFunction::EmitBuiltinExpr(unsigned BuiltinID, const CallExpr *E) {
   switch (BuiltinID) {
   default:
+    if (getContext().BuiltinInfo.isLibFunction(BuiltinID))
+      return EmitCallExpr(CGM.getBuiltinLibFunction(BuiltinID), E);
+    
     fprintf(stderr, "Unimplemented builtin!!\n");
     E->dump();
 
@@ -46,9 +50,3 @@
       
   return RValue::get(0);
 }
-
-RValue CodeGenFunction::EmitBuiltinLibFuncExpr(unsigned BuiltinID, 
-                                               const CallExpr *E) {
-  //llvm::Function *Callee = CGM.getBuiltinLibFunction(BuiltinID);
-  return RValue();
-}