[llvm] [X86] Remove redundant `cmp` before `adc` after `lzcnt` or `tzcnt` (PR #208392)

[Simon Pilgrim via llvm-commits]

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@@ -0,0 +1,155 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=znver5 | FileCheck %s
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RKSimon wrote:

Add i686 test coverage and better to use `-mattr=+bmi,+lzcnt` than a specific cpu

https://github.com/llvm/llvm-project/pull/208392