[llvm] [KnownBits] Remove `hasConflict()` assertions (PR #94568)

[Nikita Popov via llvm-commits]

nikic wrote:

There are some test failures in pre-commit CI:
```
  LLVM :: Analysis/ScalarEvolution/ashr.ll
  LLVM :: Analysis/ScalarEvolution/pr76234.ll
  LLVM :: CodeGen/AArch64/GlobalISel/form-bitfield-extract-from-sextinreg.mir
  LLVM :: CodeGen/AMDGPU/ds-sub-offset.ll
  LLVM :: Transforms/InstCombine/select-obo-peo-ops.ll
  LLVM :: Transforms/LoopStrengthReduce/lsr-term-fold-negative-testcase.ll
  LLVM-Unit :: Analysis/./AnalysisTests.exe/ValueTrackingTest/ComputeNumSignBits_PR32045
  LLVM-Unit :: IR/./IRTests.exe/DemandedBitsTest/Add
  LLVM-Unit :: IR/./IRTests.exe/DemandedBitsTest/Sub
```
I think most of these are due to the various `if (!Known.hasConflict()) Known.setAllZero();` check that you dropped. You could either adjust the test expectations, or leave dropping these checks for a later patch, so that this one can be NFC (no functional change).

https://github.com/llvm/llvm-project/pull/94568