This paper presents techniques to tightly integrate worstcase execution time (WCET) information into a compiler framework. Currently, a tight integration of WCET information into the compilation process is strongly desired, but only some ad-hoc approaches have been reported currently. Previous publications mainly used self-written WCET estimators with very limited functionality and preciseness during compilation. A very tight integration of a high quality industry-relevant WCET analyzer into a compiler was not yet achieved up to now. This work is the first to present techniques capable of achieving such a tight coupling between a compiler and the WCET analyzer aiT. This is done by automatically translating the assembly-like contents of the compiler's low-level intermediate representation (LLIR) to aiT's exchange format CRL2. Additionally, the results produced by the WCET analyzer are automatically collected and re-imported into the compiler infrastructure. The work described...