[Ada] Suppress GNAT FE up-level reference transformation for GNAT-LLVM
In the case of GNAT-LLVM, the GNAT FE no longer does expansion of
up-level references identified by the subprogram unnesting machinery
into activation record references. This is now only done by the FE when
generating C code. This expansion is already taken care of by the
gnat-llvm middle phase, so there's no benefit to also doing it in the
front end.
2019-09-19 Gary Dismukes <dismukes@adacore.com>
gcc/ada/
* exp_unst.adb (Unnest_Subprogram): Bypass the transformation of
up-level references unless Opt.Generate_C_Code is enabled.
From-SVN: r275942