[llvm] [TableGen] Avoid assignmentInAssert warning (PR #139715)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-m68k-linux-cross` running on `suse-gary-m68k-cross` while building `llvm` at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/27/builds/9973

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'LLVM :: TableGen/GlobalISelCombinerEmitter/match-table-imms.td' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen -I /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/../../../include -gen-global-isel-combiner      -combiners=MyCombiner /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-imms.td |  /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/FileCheck /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-imms.td # RUN: at line 1
+ /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen -I /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/../../../include -gen-global-isel-combiner -combiners=MyCombiner /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-imms.td
+ /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/FileCheck /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-imms.td
llvm-tblgen: /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp:2615: virtual void {anonymous}::GICombinerEmitter::emitTestSimplePredicate(llvm::raw_ostream&): Assertion `ExpectedID == ID && "combine rules are not ordered!"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen -I /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/../../../include -gen-global-isel-combiner -combiners=MyCombiner /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-imms.td
 #0 0x000000000077d15b llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen+0x77d15b)
 #1 0x000000000077a4b6 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #2 0x00007f4dcbe41580 __restore_rt (/lib64/libc.so.6+0x41580)
 #3 0x00007f4dcbe9a25c __pthread_kill_implementation (/lib64/libc.so.6+0x9a25c)
 #4 0x00007f4dcbe414b6 gsignal (/lib64/libc.so.6+0x414b6)
 #5 0x00007f4dcbe2891a abort (/lib64/libc.so.6+0x2891a)
 #6 0x00007f4dcbe2882e _nl_load_domain.cold (/lib64/libc.so.6+0x2882e)
 #7 0x00007f4dcbe392d6 (/lib64/libc.so.6+0x392d6)
 #8 0x0000000000639a63 (/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen+0x639a63)
 #9 0x0000000000476072 llvm::GlobalISelMatchTableExecutorEmitter::emitExecutorImpl(llvm::raw_ostream&, llvm::gi::MatchTable const&, llvm::ArrayRef<llvm::gi::LLTCodeGen>, llvm::ArrayRef<llvm::gi::RuleMatcher>, llvm::ArrayRef<llvm::Record const*>, llvm::ArrayRef<llvm::StringRef>, llvm::StringRef) (/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen+0x476072)
#10 0x0000000000653db2 EmitGICombiner(llvm::RecordKeeper const&, llvm::raw_ostream&) GlobalISelCombinerEmitter.cpp:0:0
#11 0x00000000007bdf9a llvm::TableGen::Emitter::ApplyCallback(llvm::RecordKeeper const&, llvm::raw_ostream&) (/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen+0x7bdf9a)
#12 0x0000000000789d81 llvm::TableGenMain(char const*, std::function<bool (llvm::raw_ostream&, llvm::RecordKeeper const&)>) (/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen+0x789d81)
#13 0x0000000000448830 tblgen_main(int, char**) (/var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/llvm-tblgen+0x448830)
#14 0x00007f4dcbe2a2ae __libc_start_call_main (/lib64/libc.so.6+0x2a2ae)
#15 0x00007f4dcbe2a379 __libc_start_main at GLIBC_2.2.5 (/lib64/libc.so.6+0x2a379)
#16 0x000000000040cfc5 _start /home/abuild/rpmbuild/BUILD/glibc-2.40/csu/../sysdeps/x86_64/start.S:117:0
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/stage1/bin/FileCheck /var/lib/buildbot/workers/suse-gary-m68k-cross/clang-m68k-linux-cross/llvm/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table-imms.td

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/139715