https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79981
--- Comment #5 from Dominik Vogt <vogt at linux dot vnet.ibm.com> --- The knowledge that the integer can only assume the values 0 and 1 seems to be hard coded. Is it possible to add value range information? With that, all conditions and arithmetics could be done with the integer, and the boolean value would only be useful if the return value is explicitly stored in memory or so. Doing calculations with the boolean type (QImode) is something we really need to avoid on s390x because it eventually results in widening the value to SImode with bit arithmetics and clobbering the condition code as a side effect.
