[flang] Add support for -acc for compatibility with nvfortran.

[ygribov]

I realize that the wrapper may be removed in few months so let me know if this is irrelevant.

[awarzynski]

This change will make the flang script support nvfortran a bit better, but that's at the cost of some extra complexity. And this script has never been meant to be particularly scalable or extensible :) @ygribov , do you envisage more such options? Or is this a one off?

flang/tools/f18/flang

182

-acc is not accepted by Flang, so it's in a yet different category. Also, the current comment is out-of-date: -fopenmp and -fopenacc _are_ in the same category as -I and -J. Would you mind updating it accordingly?

261–265

This new case makes sense, but could you make it clear that this is specifically for nvfortan? Updating the comment would be fine.

264

[ygribov]

In D117766#3266403, @awarzynski wrote:

@ygribov , do you envisage more such options? Or is this a one off?

I expect it to be one off because other relevant flags seem to already be supported. nvfortran's OpenACC is better than gfortran's one so it's generally preferred for OpenACC testing.

[ygribov]

Resolve review comments.

[awarzynski]

LGTM, thanks for addressing my comments!

flang/tools/f18/flang

categorise_files()
   done
 }
 
 # === categorise_opts ==========================================================
 #
 # Categorises compiler options into options for:
 #   * the Flang driver (either new or the "throwaway" driver)
 #   * the external Fortran driver that will generate the code
 # Most options accepted by Flang will be claimed by it. The only exceptions are
-# `-I` and `-J`.
+# `-I`, `-J`, `-fopenmp` and `-fopenacc` which are passed to both compilers
+# and `-acc` which is replaced with `-fopenacc` for compatibility with
+# external nvfortran compiler.
 #
 # INPUTS:
 #   $1 - all compiler options (array, name reference)
 # OUTPUTS:
 #   $2 - compiler options for the Flang driver (array, name reference)
 #   $3 - compiler options for the external driver (array, name reference)
 # =============================================================================
 categorise_opts()
for opt in "${all_opts[@]}"; do
     elif
       # Options that are needed for both Flang and the external driver.
       [[ $opt =~ -I.* ]] ||
       [[ $opt =~ -J.* ]] ||
       [[ $opt == "-fopenmp" ]] ||
       [[ $opt == "-fopenacc" ]]; then
       flang_opts+=($opt)
       fc_opts+=($opt)
+    elif
+      # Options that have different names in Flang and the external driver.
+      [[ $opt == "-acc" ]]; then
+      flang_opts+=("-fopenacc")
+      fc_opts+=($opt)
     else
       # All other options are claimed for the external driver.
       fc_opts+=($opt)
     fi
   done
 }
 
 # === preprocess ==============================================================