Another small thing which might be environmental... llvmjit_types.bc is getting installed into ${prefix}/lib here, but you're looking for it in ${prefix}/lib/postgresql:
gmake[3]: Entering directory '/usr/home/munro/projects/postgres/src/backend/lib' /usr/bin/install -c -m 644 llvmjit_types.bc '/home/munro/install/lib' postgres=# set jit_above_cost = 0; SET postgres=# set jit_expressions = on; SET postgres=# select 4 + 4; ERROR: LLVMCreateMemoryBufferWithContentsOfFile(/usr/home/munro/install/lib/postgresql/llvmjit_types.bc) failed: No such file or directory $ mv ~/install/lib/llvmjit_types.bc ~/install/lib/postgresql/ postgres=# select 4 + 4; ?column? ---------- 8 (1 row) -- Thomas Munro http://www.enterprisedb.com