[PATCH] Use the middle-end boolean_type_node

[FX]

> The regression with 8 bit boolean types surfaced with the z10 machine. The ABI is much older. Since
> we cannot change it anymore we should rather talk to the hardware guys to add the instruction we
> need. So for now we probably have to live with the regression in the Fortran cases since as I
> understand it your change fixes an actual problem.

As far as I understand (and Jane will correct me if I am wrong), the patch does not fix anything in particular. The idea was that, by transitioning from having all boolean expressions from “int” to “bool” (in C terms), and thus from 32-bit to 8-bit on “typical” targets, the optimizer might be able to emit more compact code. I am not sure this was tested.

So: maybe it is a case of "Profile. Don't speculate.”

FX