case madviseUnsupported:
		// Since Linux 3.18, support for madvise is optional.
		// Fall back on mmap if it's not supported.
		// _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE will unmap all the
		// pages in the old mapping, and remap the memory region.
		mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
	}

	if debug.harddecommit > 0 {
		p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)

      replacer.create<mlir::func::ReturnOp>(yield_op.getLoc(),
                                            yield_op.getOperands());
      yield_op.erase();
    }

    // Remap the captured operands in the (former) island block with newly
    // created entry block arguments in the function body.
    {
      Block &entry_block = outlined_func.getBody().front();