Follow up on a cse OpType-mismatch crash reported due to ef023cae388d
(Reland [VPlan] Expand WidenInt inductions with nuw/nsw), setting the
OpType correctly when returning from getFlagsFromIndDesc.

This patch implements a transform to hoists single-scalar replicated
loads with invariant addresses out of the vector loop to the preheader
when scoped noalias metadata proves they cannot alias with any stores in
the loop.

This enables hosting of loads we can prove do not alias any stores in
the loop due to memory runtime checks added during vectorization.

PR: https://github.com/llvm/llvm-project/pull/166247

Changes: The previous patch had to be reverted to a mismatching-OpType
assert in cse. The reduced-test has now been added corresponding to a
RVV pointer-induction, and the pointer-induction case has been updated
to use createOverflowingBinaryOp.

While at it, record VPIRFlags in VPWidenInductionRecipe.

Reverts llvm/llvm-project#163538

This is causing build failures on the two-stage RVV buildbots. e.g.
https://lab.llvm.org/buildbot/#/builders/214/builds/1363. I've shared a
reproducer and more information at
https://github.com/llvm/llvm-project/pull/163538#issuecomment-3533482822

This reverts commit 355e0f94af5adabe90ac57110ce1b47596afd4cd.

While at it, record VPIRFlags in VPWidenInductionRecipe.

This patch updates various LLVM headers to properly add the `LLVM_ABI`
and `LLVM_ABI_FOR_TEST` annotations to build LLVM as a DLL on Windows.

This effort is tracked in #109483.

Update getSCEVExprForVPValue to handle more complex expressions, to use
it in VPReplicateRecipe::comptueCost.

In particular, it supports construction SCEV expressions for
GetElementPtr VPReplicateRecipes, with operands that are
VPScalarIVStepsRecipe, VPDerivedIVRecipe and VPCanonicalIVRecipe. If we
hit a sub-expression we don't support yet, we return
SCEVCouldNotCompute.

Note that the SCEV expression is valid VF = 1: we only support
construction AddRecs for VPCanonicalIVRecipe, which is an AddRec
starting at 0 and stepping by 1. The returned SCEV expressions could be
converted to a VF specific one, by rewriting the AddRecs to ones with
the appropriate step.

Note that the logic for constructing SCEVs for GetElementPtr was
directly ported from ScalarEvolution.cpp.

Another thing to note is that we construct SCEV expression purely by
looking at the operation of the recipe and its translated operands, w/o
accessing the underlying IR (the exception being getting the source
element type for GEPs).

PR: https://github.com/llvm/llvm-project/pull/161276

Move the implementation of vputils::isSingleScalar to VPlanUtils.cpp to
enable code sharing.

Add a new Unpack VPInstruction (name to be improved) to explicitly
extract scalars values from vectors.

Test changes are movements of the extracts: they are no generated
together and also directly after the producer.

Depends on https://github.com/llvm/llvm-project/pull/155102 (included in
PR)

PR: https://github.com/llvm/llvm-project/pull/155670

Multiple places retrieve the region for a recipe. Add a helper to make
the code more compact and clearer.