A compiler and method of optimizing code by partial inlining of a subset of blocks of called blocks of code into calling blocks of code. A restart of the called blocks of code is provided for the case where non-inlined blocks of code are reached at run time. Blocks selected for partial inlining may include global side effects depending on the computer program environment. Global side effects in the selected blocks of code leading to a restart are sanitized in order to defer changes to the global state of the computer program.