Flang was not able to convert simd directive which contains nested Fortran loops. The nested Fortran loops inside SIMD directive are modelled as FIR loops and they need to be translated into LLVM MLIR dialect. Differential Revision: https://reviews.llvm.org/D131402 Reviewed by: peixin Signed-off-by: Dominik Adamski <dominik.adamski@amd.com>