[llvm] [NFC] Prefer compile-time branching in function template (PR #203698)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-aarch64-windows` running on `linaro-armv8-windows-msvc-05` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/141/builds/19553

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: functionalities/breakpoint/nested_breakpoint_commands/TestNestedBreakpointCommands.py (371 of 2570)
UNSUPPORTED: lldb-api :: functionalities/breakpoint/objc/TestObjCBreakpoints.py (372 of 2570)
PASS: lldb-api :: functionalities/breakpoint/same_cu_name/TestFileBreakpointsSameCUName.py (373 of 2570)
PASS: lldb-api :: functionalities/breakpoint/scripted_bkpt/TestScriptedResolver.py (374 of 2570)
XFAIL: lldb-api :: functionalities/breakpoint/scripted_bkpt/overrides_resolver/TestOverridesResolver.py (375 of 2570)
XFAIL: lldb-api :: functionalities/breakpoint/scripted_bkpt/was_hit/TestWasHit.py (376 of 2570)
PASS: lldb-api :: functionalities/breakpoint/source_regexp/TestSourceRegexBreakpoints.py (377 of 2570)
PASS: lldb-api :: functionalities/breakpoint/serialize/TestBreakpointSerialization.py (378 of 2570)
PASS: lldb-api :: functionalities/breakpoint/step_over_breakpoint/TestStepOverBreakpoint.py (379 of 2570)
PASS: lldb-api :: functionalities/breakpoint/thread_plan_user_breakpoint/TestThreadPlanUserBreakpoint.py (380 of 2570)
FAIL: lldb-api :: functionalities/breakpoint/two_hits_one_actual/TestTwoHitsOneActual.py (381 of 2570)
******************** TEST 'lldb-api :: functionalities/breakpoint/two_hits_one_actual/TestTwoHitsOneActual.py' FAILED ********************
Script:
--
C:/Users/tcwg/scoop/apps/python/current/python.exe C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/llvm-project/lldb\test\API\dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./lib --env LLVM_INCLUDE_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/include --env LLVM_TOOLS_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin --triple aarch64-pc-windows-msvc --build-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex --lldb-module-cache-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex/module-cache-lldb\lldb-api --clang-module-cache-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex/module-cache-clang\lldb-api --executable C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/lldb.exe --compiler C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/clang.exe --dsymutil C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/dsymutil.exe --make C:/Users/tcwg/scoop/shims/make.exe --llvm-tools-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin --lldb-obj-root C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/tools/lldb --lldb-libs-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./lib --cmake-build-type Release --skip-category=watchpoint --env LLDB_LAUNCH_FLAG_USE_PIPES=1 C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\API\functionalities\breakpoint\two_hits_one_actual -p TestTwoHitsOneActual.py
--
Exit Code: 1

Command Output (stdout):
--
Skipping the following test categories: watchpoint, libc++, libstdcxx, dwo, dsym, gmodules, debugserver, objc, fork, pexpect


--
Command Output (stderr):
--
FAIL: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_two_hits_one_actual (TestTwoHitsOneActual.TestTwoHitsOneActual.test_two_hits_one_actual)

Log Files:

 - C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\lldb-test-build.noindex\functionalities\breakpoint\two_hits_one_actual\TestTwoHitsOneActual\Failure_test_two_hits_one_actual.log

======================================================================

FAIL: test_two_hits_one_actual (TestTwoHitsOneActual.TestTwoHitsOneActual.test_two_hits_one_actual)

   There can be many tests in a test case - describe this test here.

----------------------------------------------------------------------

Traceback (most recent call last):

  File "C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\packages\Python\lldbsuite\test\decorators.py", line 160, in wrapper

    return func(*args, **kwargs)

           ^^^^^^^^^^^^^^^^^^^^^

  File "C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\API\functionalities\breakpoint\two_hits_one_actual\TestTwoHitsOneActual.py", line 23, in test_two_hits_one_actual

```

</details>

https://github.com/llvm/llvm-project/pull/203698