So, the real loop is the instruction at address 0x4004d9. But a
breakpoint that's defined at the loop line (assume line 30 in this
case) is inserted at address 0x4004d4.
(gdb) break 30
Breakpoint 1 at 0x4004d4: file test.c, line 30.
Therefore, continuing a thread that was spinning on the loop does not hit
the breakpoint. The bug is reported at
https://bugs.llvm.org/show_bug.cgi?id=49614
Tweak the infinite loop to spin on a variable to avoid this bug. The
test is unrelated to the bug.
gdb/testsuite/ChangeLog:
2021-03-29 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.mi/user-selected-context-sync.exp: Spin on a variable in
the infinite loop to avoid a Clang bug.