The `SeedCollector` class gets two new arguments: `CollectStores` and
`CollectLoads`. These replace the `sbvec-collect-seeds` cl::opt flag.
This is done to help with reusing the SeedCollector class in a future
pass. The cl::opt flag is moved to the seed collection pass:
Passes/SeedCollection.cpp

Fix the ownership of `Legality` member variable of BottomUpVec. It
should get created in runOnFunction() and get destroyed when the
function returns.

This reverts commit 31abf0774232735ad7a7d45e531497305bf99fae.

This reverts commit 1268352656f81ea173860a8002aadb88844137e7.

This patch implements a simple pass that tries to de-duplicate packs. If
there are two packing patterns inserting the exact same values in the
exact same order, then we will keep the top-most one of them. Even
though such patterns may be optimized away by subsequent passes it is
still useful to do this within the vectorizer because otherwise the cost
estimation may be off, making the vectorizer over conservative.

This patch adds a region pass that reverts the IR state unconditionally.
This is used for testing.

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

This patch implements a simple printing pass for regions. This is meant
to be used in tests and for debugging.

RegionFromBBs is a helper Sandbox IR function pass that builds a region
for each BB. This helps test region passes in isolation without relying
on other parts of the vectorizer, which is especially useful for
stress-testing.

/llvm-project/llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionAcceptOrRevert.cpp:24:8: error: unused variable 'CostBefore' [-Werror,-Wunused-variable]
  auto CostBefore = SB.getBeforeCost();
       ^
/llvm-project/llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionAcceptOrRevert.cpp:25:8: error: unused variable 'CostAfter' [-Werror,-Wunused-variable]
  auto CostAfter = SB.getAfterCost();
       ^
2 errors generated.