[llvm] [X86] LowerShift - don't prematurely lower to x86 vector shift imm instructions (PR #120282)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-remote-linux-ubuntu` running on `as-builder-9` while building `llvm` at step 16 "test-check-lldb-api".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/195/builds/2557

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

```
Step 16 (test-check-lldb-api) failure: Test just built components: check-lldb-api completed (failure)
******************** TEST 'lldb-api :: functionalities/thread/concurrent_events/TestConcurrentManySignals.py' FAILED ********************
Script:
--
/usr/bin/python3.12 /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./lib --env LLVM_INCLUDE_DIR=/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/include --env LLVM_TOOLS_DIR=/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./bin --libcxx-include-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/include/c++/v1 --libcxx-include-target-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/include/aarch64-unknown-linux-gnu/c++/v1 --libcxx-library-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./lib/aarch64-unknown-linux-gnu --arch aarch64 --build-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/lldb-test-build.noindex --lldb-module-cache-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./bin/lldb --compiler /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/bin/clang --dsymutil /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./bin/dsymutil --make /usr/bin/gmake --llvm-tools-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./bin --lldb-obj-root /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/tools/lldb --lldb-libs-dir /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/./lib --platform-url connect://jetson-agx-2198.lab.llvm.org:1234 --platform-working-dir /home/ubuntu/lldb-tests --sysroot /mnt/fs/jetson-agx-ubuntu --env ARCH_CFLAGS=-mcpu=cortex-a78 --platform-name remote-linux /home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/test/API/functionalities/thread/concurrent_events -p TestConcurrentManySignals.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 20.0.0git (https://github.com/llvm/llvm-project.git revision 49fd2dde21655f95309abb17ad1d3392afe4985f)
  clang revision 49fd2dde21655f95309abb17ad1d3392afe4985f
  llvm revision 49fd2dde21655f95309abb17ad1d3392afe4985f
Setting up remote platform 'remote-linux'
Connecting to remote platform 'remote-linux' at 'connect://jetson-agx-2198.lab.llvm.org:1234'...
Connected.
Setting remote platform working directory to '/home/ubuntu/lldb-tests'...
Skipping the following test categories: ['dsym', 'gmodules', 'debugserver', 'objc', 'lldb-dap']

--
Command Output (stderr):
--
WARNING:root:Custom libc++ is not supported for remote runs: ignoring --libcxx arguments
FAIL: LLDB (/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/bin/clang-aarch64) :: test (TestConcurrentManySignals.ConcurrentManySignals.test)
======================================================================
FAIL: test (TestConcurrentManySignals.ConcurrentManySignals.test)
   Test 100 signals from 100 threads.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 148, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 148, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/test/API/functionalities/thread/concurrent_events/TestConcurrentManySignals.py", line 17, in test
    self.do_thread_actions(num_signal_threads=100)
  File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/concurrent_base.py", line 261, in do_thread_actions
    self.assertEqual(
AssertionError: 1 != 0 : Expected main thread (finish) breakpoint to be hit once
Config=aarch64-/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/build/bin/clang
----------------------------------------------------------------------
Ran 1 test in 9.535s

FAILED (failures=1)

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/120282