llvm treats calls to some functions with names and arguments that match the -standard C library as being the C library functions, and may perform -optimizations or generate code for them under that assumption. These -functions currently include: -acos, asin, atan, atan2, ceil, cos, cosf, cosh, exp, fabs, floor, fmod, log, -log10, malloc, pow, sin, sinh, sqrt, sqrtf, sin, sinf, tan, tanh.
+standard C99 library as being the C99 library functions, and may perform +optimizations or generate code for them under that assumption. This is +something we'd like to change in the future to provide better support for +freestanding environments and non-C-based langauges.