LAA: handle 0 return from getPtrStride correctly (#124539)

getPtrStride returns 0 when the PtrScev is loop-invariant, and this is
not an erroneous value: it returns std::nullopt to communicate that

LAA: handle 0 return from getPtrStride correctly (#124539)

getPtrStride returns 0 when the PtrScev is loop-invariant, and this is
not an erroneous value: it returns std::nullopt to communicate that it
was not able to find a valid pointer stride. In analyzeLoop, we call
getPtrStride with a value_or(0) conflating the zero return value with
std::nullopt. Fix this, handling loop-invariant loads correctly.

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update_analyze_test_checks: support output from LAA (#67584)

update_analyze_test_checks.py is an invaluable tool in updating tests.
Unfortunately, it only supports output from the CostModel,
Scala

update_analyze_test_checks: support output from LAA (#67584)

update_analyze_test_checks.py is an invaluable tool in updating tests.
Unfortunately, it only supports output from the CostModel,
ScalarEvolution, and LoopVectorize analyses. Many LoopAccessAnalysis
tests use hand-crafted CHECK lines, and it is moreover tedious to
generate these CHECK lines, as the output fom the analysis is not
stable, and requires the test-writer to hand-craft FileCheck matches.
Alleviate this pain, and support output from:

$ opt -passes='print<loop-accesses>'

This patch includes several non-trivial changes including:
- Preserving whitespace at the beginning of the line, so that the LAA
output can be properly indented.
- Regexes matching the unstable output, which is basically a pointer
address hex.
- Separating is_analyze from preserve_names clearly, as the former was
formerly used as an overload for the latter.

To demonstate the utility of this patch, several tests in
LoopAccessAnalysis have been auto-generated by
update_analyze_test_checks.py.

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[LoopDist] Update the pragma info of loop distribute, NFC (#69825)

Base on D19403, the exact pragma of distribute is
`#pragma clang loop distribute`

[LAA] Convert tests to opaque pointers (NFC)

[LAA] Rename printing pass to print<access-info>.

This updates the naming for the LAA printing pass to be in line with
most other analysis printing passes.

The old name has come up as confusing mul

[LAA] Rename printing pass to print<access-info>.

This updates the naming for the LAA printing pass to be in line with
most other analysis printing passes.

The old name has come up as confusing multiple times already, e.g. in
D131924.

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[test] Remove unnecessary require<> in LoopAccessAnalysis tests

These function analyses are always available in loop passes.

[LAA] Add Memory dependence remarks.

Adds new optimization remarks when vectorization fails.

More specifically, new remarks are added for following 4 cases:

- Backward dependency
- Backward depend

[LAA] Add Memory dependence remarks.

Adds new optimization remarks when vectorization fails.

More specifically, new remarks are added for following 4 cases:

- Backward dependency
- Backward dependency that prevents Store-to-load forwarding
- Forward dependency that prevents Store-to-load forwarding
- Unknown dependency

It is important to note that only one of the sources
of failures (to vectorize) is reported by the remarks.
This source of failure may not be first in program order.

A regression test has been added to test the following cases:

a) Loop can be vectorized: No optimization remark is emitted
b) Loop can not be vectorized: In this case an optimization
remark will be emitted for one source of failure.

Reviewed By: sdesmalen, david-arm

Differential Revision: https://reviews.llvm.org/D108371

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Recommit "[LAA] Support pointer phis in loop by analyzing each incoming pointer."

SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses fo

Recommit "[LAA] Support pointer phis in loop by analyzing each incoming pointer."

SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses for each incoming pointer
value.

This results in 2 more loops vectorized in SPEC2000/186.crafty and
avoids regressions when sinking instructions before vectorizing.

Fixes PR50296, PR50288.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D102266

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[LAA] Add additional pointer phi tests.

[test][NewPM] Remove RUN lines using -analyze

Only tests in llvm/test/Analysis.

-analyze is legacy PM-specific.

This only touches files with `-passes`.

I looked through everything and made sure t

[test][NewPM] Remove RUN lines using -analyze

Only tests in llvm/test/Analysis.

-analyze is legacy PM-specific.

This only touches files with `-passes`.

I looked through everything and made sure that everything had a new PM equivalent.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D109040

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Revert "[LAA] Support pointer phis in loop by analyzing each incoming pointer."

This reverts commit 1ed7f8ede564c3b11da4fdca30c36ccbff422576.

This change can cause loop-distribute to crash in some

Revert "[LAA] Support pointer phis in loop by analyzing each incoming pointer."

This reverts commit 1ed7f8ede564c3b11da4fdca30c36ccbff422576.

This change can cause loop-distribute to crash in some cases. Revert
until I have more time to wrap up a fix.

See PR50296, PR5028 and D102266.

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[LAA] Support pointer phis in loop by analyzing each incoming pointer.

SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses for each inco

[LAA] Support pointer phis in loop by analyzing each incoming pointer.

SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses for each incoming pointer
value.

This results in 2 more loops vectorized in SPEC2000/186.crafty and
avoids regressions when sinking instructions before vectorizing.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D101286

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[LV,LAA] Add test cases with pointer phis in loops.

Pre-commits tests for D101286.