[Analysis] Teach isDereferenceableAndAlignedInLoop about SCEV predicates (#106562)

Currently if a loop contains loads that we can prove at compile time
are dereferenceable when certain conditions a

[Analysis] Teach isDereferenceableAndAlignedInLoop about SCEV predicates (#106562)

Currently if a loop contains loads that we can prove at compile time
are dereferenceable when certain conditions are satisfied the function
isDereferenceableAndAlignedInLoop will still return false because
getSmallConstantMaxTripCount will return 0 when SCEV predicates
are required. This patch changes getSmallConstantMaxTripCount to take
an optional Predicates pointer argument so that we can permit
functions such as isDereferenceableAndAlignedInLoop to consider more
cases.

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[SCEV] Regen a couple auto-gen tests

[SCEV] Print predicate backedge count only if new information available

When printing the result of SCEV's analysis, we can avoid printing
the predicated backedge taken count and the predicates if t

[SCEV] Print predicate backedge count only if new information available

When printing the result of SCEV's analysis, we can avoid printing
the predicated backedge taken count and the predicates if the predicates
are empty and no new information is provided. This helps to reduce the
verbosity of the output.

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[SCEV] Include type when printing constant max backedge taken count

When printing the result of the analysis, i8 -1 and i64 -1 are quite
different in terms of analysis quality. In a recent conversi

[SCEV] Include type when printing constant max backedge taken count

When printing the result of the analysis, i8 -1 and i64 -1 are quite
different in terms of analysis quality. In a recent conversion with
a new contributor, we ran into exactly this confusion.

Adding the type for constant scevs more globally seems worthwhile, but
introduces a much larger test diff. I'm splitting this off first since
it addresses the immediate need, and then going to do some further
changes to clarify a few related bits of analysis result output.

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[SCEV] Regenerate test checks (NFC)

There have been some minor but pervasive changes to the generated
CHECK lines, so regenerate all of them, to minimize future diffs.

[SCEV] Add additional tests for finite loop trip counts (NFC)

Add post-inc variations of tests.

[SCEV] Fix finite loop non-strict predicate simplification (PR60944)

There are a number of issues with the current code for converting
ule -> ult (etc) predicates for comparisons controlling finite

[SCEV] Fix finite loop non-strict predicate simplification (PR60944)

There are a number of issues with the current code for converting
ule -> ult (etc) predicates for comparisons controlling finite loops:

* It sets nowrap flags, which may only hold for that particular
comparison, not globally. (PR60944)
* It doesn't check that the RHS is invariant. (I'm not sure this
can cause practical issues independently of the previous point.)
* It runs before simplifications that may be more profitable. (PR54191)

This patch moves the handling for this into computeExitLimitFromICmp(),
because it is somewhat tightly coupled with assumptions in that code,
and addresses the aforementioned issues.

Fixes https://github.com/llvm/llvm-project/issues/60944.
Fixes https://github.com/llvm/llvm-project/issues/54191.

Differential Revision: https://reviews.llvm.org/D145510

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[SCEV] Add test for PR54191 (NFC)

[SCEV] Add printout of symbolic max backedge-taken and block exit count

We do compute it and use in optimizations, but never print it out. We need
to do it in order to be able to track improvements

[SCEV] Add printout of symbolic max backedge-taken and block exit count

We do compute it and use in optimizations, but never print it out. We need
to do it in order to be able to track improvements in its computation.

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[SCEV] Rename max backedge-taken count -> constant max backedge taken-count in printout

This is a preparatory step for introducing symbolic max backedge-taken count.

[ScalarEvolution] Handle <= and >= in non infinite loops

Extend scalar evolution to handle >= and <= if a loop is known to be finite and the induction variable guards the condition. Specifically, wi

[ScalarEvolution] Handle <= and >= in non infinite loops

Extend scalar evolution to handle >= and <= if a loop is known to be finite and the induction variable guards the condition. Specifically, with these assumptions lhs <= rhs is equivalent to lhs < rhs + 1 and lhs >= rhs to lhs > rhs -1.

In the case of lhs <= rhs, this is true since the only case these are not equivalent
is when rhs == unsigned/signed intmax, which would have resulted in an infinite loop.

In the case of lhs >= rhs, this is true since the only case these are not equivalent
is when rhs == unsigned/signed intmin, which would again have resulted in an infinite loop.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D118090

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