  Numerical accuracy of floating point computation is a well studied topic
which has not made its way to the end-user in scientific computing. Yet, it has
become a critical issue with the recent requirements for code modernization to
harness new highly parallel hardware and perform higher resolution computation.
To democratize numerical accuracy analysis, it is important to propose tools
and methodologies to study large use cases in a reliable and automatic way. In
this paper, we propose verificarlo, an extension to the LLVM compiler to
automatically use Monte Carlo Arithmetic in a transparent way for the end-user.
It supports all the major languages including C, C++, and Fortran. Unlike
source-to-source approaches, our implementation captures the influence of
compiler optimizations on the numerical accuracy. We illustrate how Monte Carlo
Arithmetic using the verificarlo tool outperforms the existing approaches on
various use cases and is a step toward automatic numerical analysis.
