Trivial math builtins not inlined

While compiling for -march=armv7-a, Apple Clang from Xcode 4.2 fails to inline math builtins, relatively complex ones like __builtin_fmodf as well as trivial (single instruction) ones like __builtin_lrintf.
-ffast-math -D__NO_MATH_INLINES do not help...

__builtin_lrintf is most important to me as I need fast scalar float to int rounding and there is no intrisic for that AFAIK.

ps according to Other Builtins (Using the GNU Compiler Collection (GCC)) one needs to compile with -std=c99 in order to have std math.h functions recognized as builtins, but what if I (need to) specify -std=gnu++0x?