Add support for __builtin_expect which is needed for assert,

among other things.

Also change a codegen warning to dump to stderr so it doesn't
mess with -emit-llvm output

llvm-svn: 44497

Author: ojhunt

clang/CodeGen/CGBuiltin.cpp

@@ -97,6 +97,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(unsigned BuiltinID, const CallExpr *E) {
 
     return RValue::get(Result);
   }
+  case Builtin::BI__builtin_expect: {
+    llvm::Value *Condition = EmitScalarExpr(E->getArg(0));   
+    return RValue::get(Condition);
+  }
   }
 
   return RValue::get(0);

clang/CodeGen/CGStmt.cpp

@@ -38,7 +38,7 @@ void CodeGenFunction::EmitStmt(const Stmt *S) {
       else
         EmitAggExpr(E, 0, false);
     } else {
-      printf("Unimplemented stmt!\n");
+      fprintf(stderr, "Unimplemented stmt!\n");
       S->dump(getContext().SourceMgr);
     }
     break;

clang/include/clang/AST/Builtins.def

@@ -67,5 +67,6 @@ BUILTIN(__builtin_va_start, "va&.", "n")
 BUILTIN(__builtin_va_end, "va&", "n")
 BUILTIN(__builtin_va_copy, "va&a", "n")
 BUILTIN(__builtin_memcpy, "v*v*vC*z", "n")
+BUILTIN(__builtin_expect, "iii"   , "nc")
 
 #undef BUILTIN