[Coroutines] Convert coroutine.presplit to enum attr

This is required by @nikic in https://reviews.llvm.org/D127383 to
decrease the cost to check whether a function is a coroutine and this
fixes a F

[Coroutines] Convert coroutine.presplit to enum attr

This is required by @nikic in https://reviews.llvm.org/D127383 to
decrease the cost to check whether a function is a coroutine and this
fixes a FIXME too.

Reviewed By: rjmccall, ezhulenev

Differential Revision: https://reviews.llvm.org/D127471

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[NewPM] Consistently use 'simplifycfg' rather than 'simplify-cfg'

There was an alias between 'simplifycfg' and 'simplify-cfg' in the
PassRegistry. That was the original reason for this patch, which

[NewPM] Consistently use 'simplifycfg' rather than 'simplify-cfg'

There was an alias between 'simplifycfg' and 'simplify-cfg' in the
PassRegistry. That was the original reason for this patch, which
effectively removes the alias.

This patch also replaces all occurrances of 'simplify-cfg'
by 'simplifycfg'. Reason for choosing that form for the name is
that it matches the DEBUG_TYPE for the pass, and the legacy PM name
and also how it is spelled out in other passes such as
'loop-simplifycfg', and in other options such as
'simplifycfg-merge-cond-stores'.

I for some reason the name should be changed to 'simplify-cfg' in
the future, then I think such a renaming should be more widely done
and not only impacting the PassRegistry.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D105627

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[Coroutines] Add the newly generated SCCs back to the CGSCC work queue after CoroSplit actually happened

Relevant discussion can be found at: https://lists.llvm.org/pipermail/llvm-dev/2021-January/1

[Coroutines] Add the newly generated SCCs back to the CGSCC work queue after CoroSplit actually happened

Relevant discussion can be found at: https://lists.llvm.org/pipermail/llvm-dev/2021-January/148197.html
In the existing design, An SCC that contains a coroutine will go through the folloing passes:
Inliner -> CoroSplitPass (fake) -> FunctionSimplificationPipeline -> Inliner -> CoroSplitPass (real) -> FunctionSimplificationPipeline

The first CoroSplitPass doesn't do anything other than putting the SCC back to the queue so that the entire pipeline can repeat.
As you can see, we run Inliner twice on the SCC consecutively without doing any real split, which is unnecessary and likely unintended.
What we really wanted is this:
Inliner -> FunctionSimplificationPipeline -> CoroSplitPass -> FunctionSimplificationPipeline
(note that we don't really need to run Inliner again on the ramp function after split).

Hence the way we do it here is to move CoroSplitPass to the end of the CGSCC pipeline, make it once for real, insert the newly generated SCCs (the clones) back to the pipeline so that they can be optimized, and also add a function simplification pipeline after CoroSplit to optimize the post-split ramp function.

This approach also conforms to how the new pass manager works instead of relying on an adhoc post split cleanup, making it ready for full switch to new pass manager eventually.

By looking at some of the changes to the tests, we can already observe that this changes allows for more optimizations applied to coroutines.

Reviewed By: aeubanks, ChuanqiXu

Differential Revision: https://reviews.llvm.org/D95807

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[Coroutines] Remove all legacy test command

With new pm becomes the default, the old-style test command becomes exactly the same as the new test command, i.e. the two commands are now redundant.
We

[Coroutines] Remove all legacy test command

With new pm becomes the default, the old-style test command becomes exactly the same as the new test command, i.e. the two commands are now redundant.
We should just delete the old command. (unless someone wants to add enable-new-pm=0 to all old commands.

Differential Revision: https://reviews.llvm.org/D104895

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Use optimal layout and preserve alloca alignment in coroutine frames.

Previously, we would ignore alloca alignment when building the frame
and just use the natural alignment of the allocated type.

Use optimal layout and preserve alloca alignment in coroutine frames.

Previously, we would ignore alloca alignment when building the frame
and just use the natural alignment of the allocated type. If an alloca
is over-aligned for its IR type, this could lead to a frame entry with
inadequate alignment for the downstream uses of the alloca.

Since highly-aligned fields also tend to produce poor layouts under a
naive layout algorithm, I've also switched coroutine frames to use the
new optimal struct layout algorithm.

In order to communicate the frame size and alignment to later passes,
I needed to set align+dereferenceable attributes on the frame-pointer
parameter of the resume function. This is clearly the right thing to
do, but the align attribute currently seems to result in assumptions
being added during inlining that the optimizer cannot easily remove.

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Re-land new pass manager coro-split and coro-elide

This re-applies patches https://reviews.llvm.org/D71899 and
https://reviews.llvm.org/D71900, which were reverted in
https://reviews.llvm.org/rG1105

Re-land new pass manager coro-split and coro-elide

This re-applies patches https://reviews.llvm.org/D71899 and
https://reviews.llvm.org/D71900, which were reverted in
https://reviews.llvm.org/rG11053a1cc61 and
https://reviews.llvm.org/rGe999aa38d16. The underlying problem that
caused two buildbots to fail with these patches is explained in
https://reviews.llvm.org/rG26f356350bd -- older compliers disagree with
the order in which the left- and right-hand side of an assignment in
LazyCallGraph ought to be evaluated, which caused an assertion in
SmallVector::operator[] to fire when the test suite was run.

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[Coroutines][2/6] New pass manager: coro-split

Summary:
This patch has four dependencies:

1. The first in this series of patches that implement coroutine passes in the
new pass manager: https://

[Coroutines][2/6] New pass manager: coro-split

Summary:
This patch has four dependencies:

1. The first in this series of patches that implement coroutine passes in the
new pass manager: https://reviews.llvm.org/D71898.
2. A patch that introduces an API for CGSCC passes to add new reference
edges to a `LazyCallGraph`, `updateCGAndAnalysisManagerForCGSCCPass`:
https://reviews.llvm.org/D72025.
3. A patch that introduces a `CallGraphUpdater` helper class that is
capable of mutating internal `LazyCallGraph` state in order to insert
new function nodes into a specific SCC: https://reviews.llvm.org/D70927.
4. And finally, a small edge case fix for updating `LazyCallGraph` that
patch 3 above happens to run into: https://reviews.llvm.org/D72226.

This is the second in a series of patches that ports the LLVM coroutines
passes to the new pass manager infrastructure. This patch implements
'coro-split'.

Some notes:
* Using the new CGSCC pass manager resulted in IR being printed in the
reverse order in some tests. To prevent FileCheck checks from failing due
to these reversed orders, this patch splits up test files that test
multiple different coroutine functions: specifically
coro-alloc-with-param.ll, coro-split-eh.ll, and coro-eh-aware-edge-split.ll.
* CoroSplit.cpp contained 2 overloads of `splitCoroutine`, one of which
dispatched to the other based on the coroutine ABI being used (C++20
switch-based versus Swift returned-continuation-based). I found this
confusing, especially with the additional branching based on `CallGraph`
vs. `LazyCallGraph`, so I removed the ABI-checking overload of
`splitCoroutine`.

Reviewers: GorNishanov, lewissbaker, chandlerc, jdoerfert, junparser, deadalnix, wenlei

Reviewed By: wenlei

Subscribers: wenlei, qcolombet, EricWF, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71899

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