Using llvm 4.0.1 and the latest git commit from libclc ( 17648cd846390e294feafef21c32c7106eac1e24 ): I am getting a cpu endless loop with clpeak, fixable with ctrl+c. Other samples, such as Matrix Multiply work fine. CLOVER_DEBUG=llvm,asm,clc CLOVER_OUTPUT=clover.out clpeak >dump 2>dump.err