When trying to build sci-libs/openblas, it fails with
strmm_kernel_LN.o: No such file or directory
../Makefile.tail:40: recipe for target 'libs' failed
Some user there https://github.com/xianyi/OpenBLAS/issues/657 provided a patch with can work.
Please test it and merge into tree if it works.
System uname: Linux-3.18.11-gentoo-x86_64-Intel-R-_Core-TM-_i7-4700HQ_CPU_@_2.40GHz-with-gentoo-2.2
So there seems to be no 32bit mode on that processor.