[llvm] [VPlan] Hook IR blocks into VPlan during skeleton creation (NFC) (PR #114292)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-expensive-checks-debian` running on `gribozavr4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/16/builds/10584

<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 :: Analysis/ScalarEvolution/scev-expander-existing-value-offset.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
RUN: at line 1: /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt < /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/Analysis/ScalarEvolution/scev-expander-existing-value-offset.ll -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S |/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/Analysis/ScalarEvolution/scev-expander-existing-value-offset.ll
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/Analysis/ScalarEvolution/scev-expander-existing-value-offset.ll
DominatorTree is different than a freshly computed one!
	Current:
=============================--------------------------------
Inorder Dominator Tree: DFSNumbers invalid: 3 slow queries.
  [1] %entry {4294967295,4294967295} [0]
    [2] %for.body.lr.ph {4294967295,4294967295} [1]
      [3] %vector.ph {4294967295,4294967295} [2]
        [4] %middle.block {4294967295,4294967295} [3]
          [5] %scalar.ph {4294967295,4294967295} [4]
            [6] %for.body {4294967295,4294967295} [5]
              [7] %for.end.loopexit {4294967295,4294967295} [6]
    [2] %for.end {4294967295,4294967295} [1]
Roots: %entry 

	Freshly computed tree:
=============================--------------------------------
Inorder Dominator Tree: DFSNumbers invalid: 0 slow queries.
  [1] %entry {4294967295,4294967295} [0]
    [2] %for.body.lr.ph {4294967295,4294967295} [1]
      [3] %scalar.ph {4294967295,4294967295} [2]
        [4] %for.body {4294967295,4294967295} [3]
          [5] %for.end.loopexit {4294967295,4294967295} [4]
      [3] %vector.ph {4294967295,4294967295} [2]
        [4] %middle.block {4294967295,4294967295} [3]
    [2] %for.end {4294967295,4294967295} [1]
Roots: %entry 
opt: /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7798: DenseMap<const llvm::SCEV *, llvm::Value *> llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan &, llvm::InnerLoopVectorizer &, llvm::DominatorTree *, bool, const DenseMap<const llvm::SCEV *, llvm::Value *> *): Assertion `DT->verify(DominatorTree::VerificationLevel::Fast)' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S
1.	Running pass "function(loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>)" on module "<stdin>"
2.	Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "foo"
 #0 0x0000000004698c57 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt+0x4698c57)
 #1 0x000000000469670e llvm::sys::RunSignalHandlers() (/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt+0x469670e)
 #2 0x000000000469930f SignalHandler(int) Signals.cpp:0:0
 #3 0x00007f94b2053140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x13140)
 #4 0x00007f94b1b67d51 raise (/lib/x86_64-linux-gnu/libc.so.6+0x38d51)
 #5 0x00007f94b1b51537 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22537)
 #6 0x00007f94b1b5140f (/lib/x86_64-linux-gnu/libc.so.6+0x2240f)
 #7 0x00007f94b1b606d2 (/lib/x86_64-linux-gnu/libc.so.6+0x316d2)
 #8 0x00000000037a7279 llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) (/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt+0x37a7279)
 #9 0x00000000037bc6e5 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/opt+0x37bc6e5)
...

```

</details>

https://github.com/llvm/llvm-project/pull/114292