[llvm] [polly] Reland "[DomTree] Assert non-null block for pre-dom tree" (PR #187005)

[Anthony Latsis via llvm-commits]

AnthonyLatsis wrote:

@aengelke We are hitting this assertion when building the Swift standard libraries:
```
Assertion failed: (BB && "dominator tree block must be non-null"), function getNodeIndex, file GenericDomTree.h, line 394.
5.	Running pass "constraint-elimination" on function "$s12SwiftPrivate19withArrayOfCStringsyxSaySSG_xSaySpys4Int8VGSgGXEtlF"
 9 llvm::DominatorTree::dominates(llvm::BasicBlockEdge const&, llvm::BasicBlock const*) const
10 llvm::isOverflowIntrinsicNoWrap(llvm::WithOverflowInst const*, llvm::DominatorTree const&) + 532
12 llvm::ScalarEvolution::getOperandsToCreate(llvm::Value*, llvm::SmallVectorImpl<llvm::Value*>&)
19 eliminateConstraints(...)
```

Here is what Claude came up with: https://github.com/swiftlang/llvm-project/pull/13634/changes/17af1c08ce34004de6e1e580e6a49e9be4f923c7. Would you mind taking a look?


https://github.com/llvm/llvm-project/pull/187005