perf record -b -g <command>
  perf report --branch-history

This merges the LBRs with the callgraphs.

However it would be nice if it also works without callgraphs (-g) set in
perf record, so that only the LBRs are displayed.  But currently perf
report errors in this case. For example,

  perf record -b <command>
  perf report --branch-history

  Error:
  Selected -g or --branch-history but no callchain data. Did
  you call 'perf record' without -g?

This patch displays the LBRs only even if callgraphs(-g) is not enabled
in perf record.

Change log:

v2: According to Milian Wolff's comment, change the obsolete error
message. Now the error message is:

                 ┌─Error:─────────────────────────────────────┐
                 │Selected -g or --branch-history.            │
                 │But no callchain or branch data.            │
                 │Did you call 'perf record' without -g or -b?│
                 │                                            │
                 │                                            │
                 │Press any key...                            │
                 └────────────────────────────────────────────┘

When passing the last parameter to hists__fprintf,
changes "|" to "||".

  hists__fprintf(hists, !quiet, 0, 0, rep->min_percent, stdout,
                 symbol_conf.use_callchain || symbol_conf.show_branchflag_count);
Signed-off-by: Yao Jin <yao.jin@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1494240182-28899-1-git-send-email-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>