https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122018

            Bug ID: 122018
           Summary: x86 doesn't use bitmanip to both set and test bit
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: uis9936 at gmail dot com
  Target Milestone: ---

Created attachment 62425
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62425&action=edit
Full testcase

x86 has instructions bt(bit test) and bts(bit test and set). As name suggests,
bts is equivalent to bt, but also sets bit. GCC can generate bt when the bit is
only tested, bts when bit is only set, but can't generate bts when bit is both
tested and set. It can be verified by commenting line 5 or 6 of provided
testcase.

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