This is the same fix as 23aeadb89df38406dc4d929d08286f7ce31040eb,
just for CloneScopedAliasMetadata rather than PropagateCallSiteMetadata.
In this case the previous outcome was incorrectly dropped metadata,
as it was not part of the computed metadata map.
The real change in the test is that the first load now retains
metadata, the rest of the changes are due to changes in metadata
numbering.
The VMap also contains a mapping from Argument => Instruction,
where the instruction is part of the original function, not the
inlined one. The code was assuming that all the instructions in
the VMap were inlined.
This was a pre-existing problem for the loop access metadata, but
was extended to the more common noalias metadata by
27f647d117087ca11959e232e6443f4aee31e966, thus causing miscompiles.
There is a similar assumption inside CloneAliasScopeMetadata(), so
that one likely needs to be fixed as well.
Like inlineCallIfPossible and InlinerPass, after inlining mergeAttributesForInlining
should be called to merge callee's attributes to caller. But it is not called in
AlwaysInliner, causes caller's attributes inconsistent with inlined code.
Attached test case demonstrates that attribute "min-legal-vector-width"="512" is
not merged into caller without this patch, and it causes failure in SelectionDAG
when lowering the inlined AVX512 intrinsic.
Differential Revision: https://reviews.llvm.org/D91446
When inlining `mustprogress` functions, if the caller or the callee has
the attribute, we drop the function attribute. The loops that have the
`llvm.loop.mustprogress` metadata keep their metadata. We do not need to
add new loop metadata to inlined functions because the patch in D86841
already adds the relevant loop metadata in all of the necessary places.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D87262
```
// The legacy PM CGPassManager discovers SCCs this way:
for function in the source order
tarjanSCC(function)
// While the new PM CGSCCPassManager does:
for function in the reversed source order [1]
discover a reference graph SCC
build call graph SCCs inside the reference graph SCC
```
In the common cases, reference graph ~= call graph, the new PM order is
undesired because for `a | b | c` (3 independent functions), the new PM will
process them in the reversed order: c, b, a. If `a <-> b <-> c`, we can see
that `-print-after-all` will report the sole SCC as `scc: (c, b, a)`.
This patch corrects the iteration order. The discovered SCC order will match
the legacy PM in the common cases.
For some tests (`Transforms/Inline/cgscc-*.ll` and
`unittests/Analysis/CGSCCPassManagerTest.cpp`), the behaviors are dependent on
the SCC discovery order and there are too many check lines for the particular
order. This patch simply reverses the function order to avoid changing too many
check lines.
Differential Revision: https://reviews.llvm.org/D90566
Previously, !noalias and !alias.scope metadata on the call site was
applied as part of CloneAliasScopeMetadata(), which short-circuits
if the callee does not use any noalias metadata itself. However,
these two things have no relation to each other.
Consistently apply !noalias and !alias.scope metadata by integrating
this into an existing function that handled !llvm.access.group and
!llvm.mem.parallel_loop_access metadata. The handling for all of
these metadata kinds essentially the same.
prune-eh will not be ported to the NPM. Instead, a combination of
function-attrs and simplifycfg should be used (as described in
https://reviews.llvm.org/D44415).
This pins most tests using -prune-eh to the legacy PM. Some of these
were testing legacy PM infra (mostly the CGPassManager). Some of these
can be tested in the NPM using function-attrs and simplifycfg.
One interesting case is simplenoreturntest.ll. function-attrs +
simplifycfg does not yet make a caller of a caller of a noreturn
function end with unreachable like prune-eh does. That can be added in
the future.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D90012
It's currently ambiguous in IR whether the source language explicitly
did not want a stack a stack protector (in C, via function attribute
no_stack_protector) or doesn't care for any given function.
It's common for code that manipulates the stack via inline assembly or
that has to set up its own stack canary (such as the Linux kernel) would
like to avoid stack protectors in certain functions. In this case, we've
been bitten by numerous bugs where a callee with a stack protector is
inlined into an __attribute__((__no_stack_protector__)) caller, which
generally breaks the caller's assumptions about not having a stack
protector. LTO exacerbates the issue.
While developers can avoid this by putting all no_stack_protector
functions in one translation unit together and compiling those with
-fno-stack-protector, it's generally not very ergonomic or as
ergonomic as a function attribute, and still doesn't work for LTO. See also:
https://lore.kernel.org/linux-pm/20200915172658.1432732-1-rkir@google.com/https://lore.kernel.org/lkml/20200918201436.2932360-30-samitolvanen@google.com/T/#u
Typically, when inlining a callee into a caller, the caller will be
upgraded in its level of stack protection (see adjustCallerSSPLevel()).
By adding an explicit attribute in the IR when the function attribute is
used in the source language, we can now identify such cases and prevent
inlining. Block inlining when the callee and caller differ in the case that one
contains `nossp` when the other has `ssp`, `sspstrong`, or `sspreq`.
Fixes pr/47479.
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D87956
The devirtualization wrapper misses cases where if it wraps a pass
manager, an individual pass may devirtualize an indirect call created by
a previous pass. For example, inlining may create a new indirect call
which is devirtualized by instcombine. Currently the devirtualization
wrapper will not see that because it only checks cgscc edges at the very
beginning and end of the pass (manager) it wraps.
This fixes some tests testing this exact behavior in the legacy PM.
This piggybacks off of updateCGAndAnalysisManagerForPass()'s detection
of promoted ref to call edges.
This supercedes one of the previous mechanisms to detect
devirtualization by keeping track of potentially promoted call
instructions via WeakTrackingVHs.
There is one more existing way of detecting devirtualization, by
checking if the number of indirect calls has decreased and the number of
direct calls has increased in a function. It handles cases where calls
to functions without definitions are promoted, and some tests rely on
that. LazyCallGraph doesn't track edges to functions without
definitions so this part can't be removed in this change.
check-llvm and check-clang with -abort-on-max-devirt-iterations-reached
on by default doesn't show any failures outside of tests specifically
testing it so it doesn't needlessly rerun passes more than necessary.
(The NPM -O2/3 pipeline run the inliner/function simplification pipeline
under a devirtualization repeater pass up to 4 times by default).
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D89587
An alwaysinline function may not get inlined in inliner-wrapper due to
the inlining order.
Previously for the following, the inliner would first inline @a() into @b(),
```
define void @a() {
entry:
call void @b()
ret void
}
define void @b() alwaysinline {
entry:
br label %for.cond
for.cond:
call void @a()
br label %for.cond
}
```
making @b() recursive and unable to be inlined into @a(), ending at
```
define void @a() {
entry:
call void @b()
ret void
}
define void @b() alwaysinline {
entry:
br label %for.cond
for.cond:
call void @b()
br label %for.cond
}
```
Running always-inliner first makes sure that we respect alwaysinline in more cases.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46945.
Reviewed By: davidxl, rnk
Differential Revision: https://reviews.llvm.org/D86988
D70365 allows us to make attributes default. This is a follow up to
actually make nosync, nofree and willreturn default. The approach we
chose, for now, is to opt-in to default attributes to avoid introducing
problems to target specific intrinsics. Intrinsics with default
attributes can be created using `DefaultAttrsIntrinsic` class.
alloca-dbgdeclare-merge.ll:
alloca-merge-align.ll:
array_merge.ll:
NPM inliner does not merge allocas
delete-call.ll:
NPM inliner does not delete readonly calls
externally_available.ll:
NPM inliner does not delete available_externally functions
inline-cold-callee.ll:
inline-hot-callee.ll:
inline-hot-callee.ll has a comment saying it only applies to legacy PM,
I assume same for inline-cold-callee.ll
devirtualize-2.ll:
inline-hot-callsite:
monster_scc.ll:
pr22285.ll:
already has legacy and new PM RUN lines
inline-cold.ll:
profile-summary required to see callee as cold
prof-update-sample.ll:
profile-summary required to update branch_weights
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D89093
NOTE: There is a mailing list discussion on this: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137632.html
Complemantary to the assumption outliner prototype in D71692, this patch
shows how we could simplify the code emitted for an alignemnt
assumption. The generated code is smaller, less fragile, and it makes it
easier to recognize the additional use as a "assumption use".
As mentioned in D71692 and on the mailing list, we could adopt this
scheme, and similar schemes for other patterns, without adopting the
assumption outlining.
When inlining functions containing allocas of scalable vectors we
cannot specify the size in the lifetime markers, since we don't
know this at compile time.
Added new test here:
test/Transforms/Inline/AArch64/sve-alloca-merge.ll
Differential Revision: https://reviews.llvm.org/D87139
As discussed in D86843, -earlycse-debug-hash should be used in more regression
tests to catch inconsistency between the hashing and the equivalence check.
Differential Revision: https://reviews.llvm.org/D86863
The NPM doesn't support call-site alwaysinline as described in the comments.
Also make NPM runs more similar to legacy PM runs.
Reviewed By: ychen, asbirlea
Differential Revision: https://reviews.llvm.org/D86663
We only need the C++ type and the corresponding TF Enum. The other
parameter was used for the output spec json file, but we can just
standardize on the C++ type name there.
Differential Revision: https://reviews.llvm.org/D86549
If we use training algorithms that don't need partial rewards, we don't
need to worry about an ir2native model. In that case, training logs
won't contain a 'delta_size' feature either (since that's the partial
reward).
Differential Revision: https://reviews.llvm.org/D86481
Different training algorithms may produce models that, besides the main
policy output (i.e. inline/don't inline), produce additional outputs
that are necessary for the next training stage. To facilitate this, in
development mode, we require the training policy infrastructure produce
a description of the outputs that are interesting to it, in the form of
a JSON file. We special-case the first entry in the JSON file as the
inlining decision - we care about its value, so we can guide inlining
during training - but treat the rest as opaque data that we just copy
over to the training log.
Differential Revision: https://reviews.llvm.org/D85674
Allow inlining only when the Callee has a subset of the Caller's
features. In principle, we should be able to inline regardless of any
features because WebAssembly supports features at module granularity,
not function granularity, but without this restriction it would be
possible for a module to "forget" about features if all the functions
that used them were inlined.
Requested in PR46812.
Differential Revision: https://reviews.llvm.org/D85494
We don't want mandatory events in the training log. We do want to handle
them, to keep the native size accounting accurate, but that's all.
Fixed the code, also expanded the test to capture this.
Differential Revision: https://reviews.llvm.org/D85373
If an analysis is actually invalidated, there's already a log statement
for that: 'Invalidating analysis: FooAnalysis'.
Otherwise the statement is not very useful.
Reviewed By: asbirlea, ychen
Differential Revision: https://reviews.llvm.org/D84981
To match NewPM pass name, and also for readability.
Also rename rpo-functionattrs -> rpo-function-attrs while we're here.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D84694
Summary:
This is the InlineAdvisor used in 'development' mode. It enables two
scenarios:
- loading models via a command-line parameter, thus allowing for rapid
training iteration, where models can be used for the next exploration
phase without requiring recompiling the compiler. This trades off some
compilation speed for the added flexibility.
- collecting training logs, in the form of tensorflow.SequenceExample
protobufs. We generate these as textual protobufs, which simplifies
generation and testing. The protobufs may then be readily consumed by a
tensorflow-based training algorithm.
To speed up training, training logs may also be collected from the
'default' training policy. In that case, this InlineAdvisor does not
use a model.
RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-April/140763.html
Reviewers: jdoerfert, davidxl
Subscribers: mgorny, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83733
This allows tracking the in-memory type of a pointer argument to a
function for ABI purposes. This is essentially a stripped down version
of byval to remove some of the stack-copy implications in its
definition.
This includes the base IR changes, and some tests for places where it
should be treated similarly to byval. Codegen support will be in a
future patch.
My original attempt at solving some of these problems was to repurpose
byval with a different address space from the stack. However, it is
technically permitted for the callee to introduce a write to the
argument, although nothing does this in reality. There is also talk of
removing and replacing the byval attribute, so a new attribute would
need to take its place anyway.
This is intended avoid some optimization issues with the current
handling of aggregate arguments, as well as fixes inflexibilty in how
frontends can specify the kernel ABI. The most honest representation
of the amdgpu_kernel convention is to expose all kernel arguments as
loads from constant memory. Today, these are raw, SSA Argument values
and codegen is responsible for turning these into loads.
Background:
There currently isn't a satisfactory way to represent how arguments
for the amdgpu_kernel calling convention are passed. In reality,
arguments are passed in a single, flat, constant memory buffer
implicitly passed to the function. It is also illegal to call this
function in the IR, and this is only ever invoked by a driver of some
kind.
It does not make sense to have a stack passed parameter in this
context as is implied by byval. It is never valid to write to the
kernel arguments, as this would corrupt the inputs seen by other
dispatches of the kernel. These argumets are also not in the same
address space as the stack, so a copy is needed to an alloca. From a
source C-like language, the kernel parameters are invisible.
Semantically, a copy is always required from the constant argument
memory to a mutable variable.
The current clang calling convention lowering emits raw values,
including aggregates into the function argument list, since using
byval would not make sense. This has some unfortunate consequences for
the optimizer. In the aggregate case, we end up with an aggregate
store to alloca, which both SROA and instcombine turn into a store of
each aggregate field. The optimizer never pieces this back together to
see that this is really just a copy from constant memory, so we end up
stuck with expensive stack usage.
This also means the backend dictates the alignment of arguments, and
arbitrarily picks the LLVM IR ABI type alignment. By allowing an
explicit alignment, frontends can make better decisions. For example,
there's real no advantage to an aligment higher than 4, so a frontend
could choose to compact the argument layout. Similarly, there is a
high penalty to using an alignment lower than 4, so a frontend could
opt into more padding for small arguments.
Another design consideration is when it is appropriate to expose the
fact that these arguments are all really passed in adjacent
memory. Currently we have a late IR optimization pass in codegen to
rewrite the kernel argument values into explicit loads to enable
vectorization. In most programs, unrelated argument loads can be
merged together. However, exposing this property directly from the
frontend has some disadvantages. We still need a way to track the
original argument sizes and alignments to report to the driver. I find
using some side-channel, metadata mechanism to track this
unappealing. If the kernel arguments were exposed as a single buffer
to begin with, alias analysis would be unaware that the padding bits
betewen arguments are meaningless. Another family of problems is there
are still some gaps in replacing all of the available parameter
attributes with metadata equivalents once lowered to loads.
The immediate plan is to start using this new attribute to handle all
aggregate argumets for kernels. Long term, it makes sense to migrate
all kernel arguments, including scalars, to be passed indirectly in
the same manner.
Additional context is in D79744.
due to the performance bugs filed in https://bugs.llvm.org/show_bug.cgi?id=46753.
An SROA change soon may obviate some of these problems.
This reverts commit 8d09f20798ac180b1749276bff364682ce0196ab.
