Merge pull request #35882 from gaurav1086:hlo_parser_nullptr_derefere…

…ncing

PiperOrigin-RevId: 291440430
Change-Id: Ie588fccf880c234f15140421cabf993c606e3017

tensorflow/compiler/xla/service/hlo_parser.cc

@@ -635,6 +635,7 @@ bool HloParserImpl::ParseInstructionList(HloComputation** computation,
     // This means some instruction was marked as ROOT but we didn't find it in
     // the pool, which should not happen.
     if (root_node == nullptr) {
+      // LOG(FATAL) crashes the program by calling abort().
       LOG(FATAL) << "instruction " << root_name
                  << " was marked as ROOT but the parser has not seen it before";
     }