[llvm] [SelectionDAG] Expand CTTZ_ELTS[_ZERO_POISON] and handle splitting (PR #185605)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 132030 tests passed
* 2991 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.CodeGen/X86/intrinsic-cttz-elts.ll</summary>

```
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\llc.exe -mtriple=x86_64-unknown-unknown < C:\_work\llvm-project\llvm-project\llvm\test\CodeGen\X86\intrinsic-cttz-elts.ll | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\llvm\test\CodeGen\X86\intrinsic-cttz-elts.ll
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\llc.exe' -mtriple=x86_64-unknown-unknown
# .---command stderr------------
# | PromoteIntegerOperand Op #0: t8: i8 = cttz_elts t7
# | 
# | LLVM ERROR: Do not know how to promote this operator's operand!
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0.	Program arguments: c:\\_work\\llvm-project\\llvm-project\\build\\bin\\llc.exe -mtriple=x86_64-unknown-unknown
# | 1.	Running pass 'Function Pass Manager' on module '<stdin>'.
# | 2.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@ctz_v8i16'
# | Exception Code: 0xC000001D
# |  #0 0x00007ff7f7f57226 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x2cf7226)
# |  #1 0x00007ffa0efabb04 (C:\Windows\System32\ucrtbase.dll+0x7bb04)
# |  #2 0x00007ffa0efacad1 (C:\Windows\System32\ucrtbase.dll+0x7cad1)
# |  #3 0x00007ff7f595690a (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6f690a)
# |  #4 0x00007ff7f59566e5 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6f66e5)
# |  #5 0x00007ff7f96d46a3 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x44746a3)
# |  #6 0x00007ff7f80f99f0 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x2e999f0)
# |  #7 0x00007ff7f810000a (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x2ea000a)
# |  #8 0x00007ff7f590d290 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6ad290)
# |  #9 0x00007ff7f590c7c0 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6ac7c0)
# | #10 0x00007ff7f590bd86 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6abd86)
# | #11 0x00007ff7f5907d5a (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6a7d5a)
# | #12 0x00007ff7f709958c (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x1e3958c)
# | #13 0x00007ff7f5904e04 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x6a4e04)
# | #14 0x00007ff7f5ca9d23 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0xa49d23)
# | #15 0x00007ff7f5719a09 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x4b9a09)
# | #16 0x00007ff7f572249d (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x4c249d)
# | #17 0x00007ff7f571a688 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x4ba688)
# | #18 0x00007ff7f5267908 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x7908)
# | #19 0x00007ff7f5264b76 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x4b76)
# | #20 0x00007ff7f9a23840 (c:\_work\llvm-project\llvm-project\build\bin\llc.exe+0x47c3840)
# | #21 0x00007ffa12ec4cb0 (C:\Windows\System32\KERNEL32.DLL+0x14cb0)
# | #22 0x00007ffa2017edcb (C:\Windows\SYSTEM32\ntdll.dll+0x7edcb)
# `-----------------------------
# error: command failed with exit status: 0xc000001d
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\llvm\test\CodeGen\X86\intrinsic-cttz-elts.ll'
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\llvm\test\CodeGen\X86\intrinsic-cttz-elts.ll
# `-----------------------------
# error: command failed with exit status: 2

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/185605