This reverts commit 8dd160f4767f971572eac065c8650d9202ff5bf9.

The recommit contains an adjustment to planContainsAdditionalSimplifications,
which considers changes to the original predicate for compares.

Original commit message:

Add simplification to fold negation into a compare, if the negation is
the only user of the compare. This removes a number of redundant
negations.

Alive2 Proofs for FPCMP test changes:  https://alive2.llvm.org/ce/z/WGDz9U

PR: https://github.com/llvm/llvm-project/pull/129430

Follow-up to dfca6c0d3bf9d1a056 to extend isUnrolled handle any unrolled
VPlan, which means there's a single UF, but it will be > 1 if unrolling
took place.

After unrolling, there may be additional simplifications that can be
applied. One example is removing SCALAR-STEPS for the first part where
only the first lane is demanded.

This removes redundant adds of 0 from a large number of tests (~200),
many which I am still working on updating.

In preparation for removing redundant WideIV steps added in
https://github.com/llvm/llvm-project/pull/119284.

PR: https://github.com/llvm/llvm-project/pull/123655

Reverts llvm/llvm-project#129430

this seems to have introduced a divergence between legacy and
VPlan-based cost model

https://lab.llvm.org/buildbot/#/builders/30/builds/17159

Add simplification to fold negation into a compare, if the negation is
the only user of the compare. This removes a number of redundant
negations.

Alive2 Proofs for FPCMP test changes:  https://alive2.llvm.org/ce/z/WGDz9U

PR: https://github.com/llvm/llvm-project/pull/129430

This just copies the same conservative definition from mayWriteToMemory,
and enables more VPInstructions to be hoisted out in LICM.

I think this should give more accurate costs, and I was able to build
llvm-test-suite without the legacy-vplan cost model assertion going off.

Add initial transform to move out loop-invariant recipes.

This also helps to fix a divergence between legacy and VPlan-based cost
model due to legacy using ScalarEvolution::isLoopInvariant in some
cases.

Fixes https://github.com/llvm/llvm-project/issues/107501.

PR: https://github.com/llvm/llvm-project/pull/107894

This change allows to consider compare instructions in the loop with
multiple use inside the loop and outside.

This change allows to vectorise this loop:
int foo(float* a, int n) {
  _Bool any = 0;
  _Bool all = 1;
  for (int i = 0; i < n; i++) {
    if (a[i] < 0.0f) {
      any = 1;
    } else {
      all = 0;
    }
  }
  return all ? 1 : any ? 2 : 3;
}