After more considerations and experience, switch to one of the
alternative plan for HLFIR variable that will avoid requiring naming
designators and having to maintain and update names in attributes after
inlining of code duplication.
The cost is the increase of fir.box usage, which in most cases should
be removed when lowering from HLFIR to FIR.
Differential Revision: https://reviews.llvm.org/D137634
This document describes a new HLFIR dialect with a new value type
(hlfir.expr) and some new higher level FIR operations to make lowering
to FIR more straightforward and make pattern matching of high level
Fortran concepts (array and character assignments, character operations,
and transformational intrinsics) easier in FIR.
This should allow implementing the remaining gaps in Fortran 95 features
without increasing the lowering code complexity too much, and get a
clean start for the remaining F2003 and F2018 features.
Differential Revision: https://reviews.llvm.org/D134285
