[opt-viewer] Remove positional arg checks (NFC)

Summary:
opt-stats.py and opt-viewer.py's argument parsers both take a positional
argument 'yaml_files'. Positional arguments in Python's argparse module are
required by default, so the subsequent checks for `len(args.yaml_files) == 0`
are unnecessary -- if the length was zero, then the call to
`parser.parse_args()` would have thrown an error already.

Because there is no way for `len(args.yaml_files)` to be zero at these
points, removing the code is NFC.

Reviewers: anemet, davidxl

Reviewed By: anemet

Subscribers: llvm-commits, fhahn

Differential Revision: https://reviews.llvm.org/D34567

llvm-svn: 306147

llvm/utils/opt-viewer/opt-stats.py

@@ -24,10 +24,6 @@ if __name__ == '__main__':
         help='Max job count (defaults to %(default)s, the current CPU count)')
     args = parser.parse_args()
 
-    if len(args.yaml_files) == 0:
-        parser.print_help()
-        sys.exit(1)
-
     if args.jobs == 1:
         pmap = map
     else:

llvm/utils/opt-viewer/opt-viewer.py

@@ -216,10 +216,6 @@ if __name__ == '__main__':
         help='set source directory')
     args = parser.parse_args()
 
-    if len(args.yaml_files) == 0:
-        parser.print_help()
-        sys.exit(1)
-
     if args.jobs == 1:
         pmap = map
     else: