[llvm] [SelectionDAG] Fix missed optimization for CLMUL where one operand is all ones (PR #200592)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lld-x86_64-ubuntu-fast` running on `as-builder-4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/33/builds/37514

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/X86/clmul.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/llc < /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll -mtriple=x86_64-- -mattr=+sse2    | /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll --check-prefixes=CHECK,SCALAR
# executed command: /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/llc -mtriple=x86_64-- -mattr=+sse2
# executed command: /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll --check-prefixes=CHECK,SCALAR
# RUN: at line 3
/home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/llc < /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll -mtriple=x86_64-- -mattr=+sse2,+pclmul | /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll --check-prefixes=CHECK,SSE-PCLMUL,SSE2-PCLMUL
# executed command: /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/llc -mtriple=x86_64-- -mattr=+sse2,+pclmul
# executed command: /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll --check-prefixes=CHECK,SSE-PCLMUL,SSE2-PCLMUL
# .---command stderr------------
# | /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll:3956:20: error: SSE-PCLMUL-NEXT: is not on the line after the previous match
# | ; SSE-PCLMUL-NEXT: movzbl %dil, %eax
# |                    ^
# | <stdin>:440:2: note: 'next' match was here
# |  movzbl %dil, %eax
# |  ^
# | <stdin>:437:9: note: previous match ended here
# | # %bb.0:
# |         ^
# | <stdin>:438:1: note: non-matching line after previous match is here
# |  movl $65535, %eax # imm = 0xFFFF
# | ^
# | /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll:4227:20: error: SSE-PCLMUL-NEXT: is not on the line after the previous match
# | ; SSE-PCLMUL-NEXT: movzbl %dil, %eax
# |                    ^
# | <stdin>:508:2: note: 'next' match was here
# |  movzbl %dil, %eax
# |  ^
# | <stdin>:505:9: note: previous match ended here
# | # %bb.0:
# |         ^
# | <stdin>:506:1: note: non-matching line after previous match is here
# |  movl $65535, %eax # imm = 0xFFFF
# | ^
# | 
# | Input file: <stdin>
# | Check file: /home/buildbot/worker/as-builder-4/ramdisk/lld-x86_64/llvm-project/llvm/test/CodeGen/X86/clmul.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            .
# |            .
# |            .
# |          435:  .type clmulr_i8_allones, at function 
...

```

</details>

https://github.com/llvm/llvm-project/pull/200592