This change enables llvm-profgen to use accurate context-sensitive post-optimization function byte size as a cost proxy to drive global preinline decisions.
To do this, BinarySizeContextTracker is introduced to track function byte size under different inline context during disassembling. In preinliner, we can not query context byte size under switch `context-cost-for-preinliner`. The tracker uses a reverse trie to keep size of functions under different context (callee as parent, caller as child), and it can give best/longest possible matching context size for given input context.
The new size cost is off by default. There're a few TODOs that needs to addressed: 1) avoid dangling string from `Offset2LocStackMap`, which will be addressed in split context work; 2) using inlinee's entry probe to make sure we have correct zero size for inlinee that's completely optimized away after inlining. Some tuning is also needed.
Differential Revision: https://reviews.llvm.org/D108180
This patch implements Flow Sensitive Sample FDO (FSAFDO) profile
loader. We have two profile loaders for FS profile,
one before RegAlloc and one before BlockPlacement.
To enable it, when -fprofile-sample-use=<profile> is specified,
add "-enable-fs-discriminator=true \
-disable-ra-fsprofile-loader=false \
-disable-layout-fsprofile-loader=false"
to turn on the FS profile loaders.
Differential Revision: https://reviews.llvm.org/D107878
Currently, AAKernelInfo will fail on an assertion if we attempt to run
it on a kernel without the init / deinit runtime calls. However, this
occurs for global constructors on the device. This will cause OpenMPOpt
to crash whenever global constructors are present. This patch removes
this assertion and just gives up instead.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D108258
In the provided test case, we were trying to set the global's
initializer to `i32* null` when the global's value type was `@0`.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D108232
This patch adds an extra option to print the module after running one of
the OpenMPOpt passes if debugging is enabled. This makes it much easier
to inspect the effects of this pass when doing debugging.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D108146
AttributeList::hasAttribute() is confusing, use clearer methods like
hasParamAttr()/hasRetAttr().
Add hasRetAttr() since it was missing from AttributeList.
Besides SPMDization, other analysis and optimization for original, frontend-generated SPMD regions uses information from the AAKernelInfoFunction attribute. This fix makes sure disabling SPMDization through the corresponding option applies only to generic mode regions, which should not be SPMDized, while it leaves unaffected the attribute state of original SPMD regions.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D108001
PHI nodes are not pass through but change their value, we have to
account for that to avoid missing stores.
Follow up for D107798 to fix PR51249 for good.
Differential Revision: https://reviews.llvm.org/D107808
AAPointerInfoFloating needs to visit all uses and some multiple times if
we go through PHI nodes. Attributor::checkForAllUses keeps a visited set
so we don't recurs endlessly. We now allow recursion for non-phi uses so
we track all pointer offsets via PHI nodes properly without endless
recursion.
This replaces the first attempt D107579.
Differential Revision: https://reviews.llvm.org/D107798
To avoid simplification with wrong constants we need to make sure we
know that we won't perform specific optimizations based on the users
request. The non-SPMDzation and non-CustomStateMachine flags did only
prevent the final transformation but allowed to value simplification
to go ahead.
Differential Revision: https://reviews.llvm.org/D107862
The may get changed before specialization by RunSCCPSolver. In other
words, the pass may change the function without specialization happens.
Add test and comment to reveal this.
And it may return No Changed if the function get changed by
RunSCCPSolver before the specialization. It looks like a potential bug.
Test Plan: check-all
Reviewed By: https://reviews.llvm.org/D107622
Differential Revision: https://reviews.llvm.org/D107622
Noticed that the computation for function specialization cost of a
function wouldn't change during the traversal of the arguments for the
function. We could hoist the computation out of the traversal. I
observed about ~1% improvement on compile time for spec2017. But I guess
it may not be precise. This should be NFC and fine.
Reviewed By: Sjoerd Meijer
Differential Revision: https://reviews.llvm.org/D107621
Now the recursive functions may get specialized many times when
`func-specialization-max-iters` increases. See discussion in
https://reviews.llvm.org/D106426 for details.
This patch expands SPMDization (converting generic execution mode to SPMD for target regions) by guarding code regions that should be executed only by the main thread. Specifically, it generates guarded regions, which only the main thread executes, and the synchronization with worker threads using simple barriers. For correctness, the patch aborts SPMDization for target regions if the same code executes in a parallel region, thus must be not be guarded. This check is implemented using the ParallelLevels AA.
Reviewed By: jhuber6
Differential Revision: https://reviews.llvm.org/D106892
This adds support for specialising recursive functions. For example:
int Global = 1;
void recursiveFunc(int *arg) {
if (*arg < 4) {
print(*arg);
recursiveFunc(*arg + 1);
}
}
void main() {
recursiveFunc(&Global);
}
After 3 iterations of function specialisation, followed by inlining of the
specialised versions of recursiveFunc, the main function looks like this:
void main() {
print(1);
print(2);
print(3);
}
To support this, the following has been added:
- Update the solver and state of the new specialised functions,
- An optimisation to propagate constant stack values after each iteration of
function specialisation, which is necessary for the next iteration to
recognise the constant values and trigger.
Specialising recursive functions is (at the moment) controlled by option
-func-specialization-max-iters and is opt-in for compile-time reasons. I.e.,
the default is -func-specialization-max-iters=1, but for the example above we
would need to use -func-specialization-max-iters=3. Future work is to see if we
can increase the default, or improve the cost-model/heuristics to control
compile-times.
Differential Revision: https://reviews.llvm.org/D106426
Currently, in OptimizeGlobalAddressOfMalloc, the transformation for global loads assumes that they have the same Type. With the support of ConstantExpr (https://reviews.llvm.org/D106589), this may not be true any more (as seen in the test case), and we miss the code to handle this, This is to fix that.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D107397
I'm working on extending the OptimizeGlobalAddressOfMalloc to handle some more general cases. This is to add support of the ConstantExpr use of the global variables. The function allUsesOfLoadedValueWillTrapIfNull is now iterative with the added CE use of GV. Also, the recursive function valueIsOnlyUsedLocallyOrStoredToOneGlobal is changed to iterative using a worklist with the GEP case added.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D106589
This work provides four flags to disable four different sets of OpenMP optimizations. These flags take effect in llvm/lib/Transforms/IPO/OpenMPOpt.cpp and include the following:
- openmp-opt-disable-deglobalization: Defaults to false, adding this flag sets the variable DisableOpenMPOptDeglobalization to true. This prevents AA registration for HeapToStack and HeapToShared.
- openmp-opt-disable-spmdization: Defaults to false, adding this flag sets the variable DisableOpenMPOptSPMDization to true. This indicates a pessimistic fixpoint in changeToSPMDMode.
- openmp-opt-disable-folding: Defaults to false, adding this flag sets the variable DisableOpenMPOptFolding to true. This indicates a pessimistic fixpoint in the attributor init for AAFoldRuntimeCall.
- openmp-opt-disable-state-machine-rewrite: Defaults to false, adding this flag sets the variable DisableOpenMPOptStateMachineRewrite to true. This first prevents changes to the state machine in rewriteDeviceCodeStateMachine by returning before changes are made, and if a custom state machine is built in buildCustomStateMachine, stops by returning a pessimistic fixpoint.
Reviewed By: jhuber6
Differential Revision: https://reviews.llvm.org/D106802
The current implementation of function internalization creats a copy of each
function and replaces every use. This has the downside that the external
versions of the functions will call into the internalized versions of the
functions. This prevents them from being fully independent of eachother. This
patch replaces the current internalization scheme with a method that creates
all the copies of the functions intended to be internalized first and then
replaces the uses as long as their caller is not already internalized.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D106931
The device runtime contains several calls to `__kmpc_get_hardware_num_threads_in_block`
and `__kmpc_get_hardware_num_blocks`. If the thread_limit and the num_teams are constant,
these calls can be folded to the constant value.
In this patch we use the already introduced `AAFoldRuntimeCall` and the `NumTeams` and
`NumThreads` kernel attributes (to be introduced in a different patch) to fold these functions.
The code checks all the kernels, and if their attributes match, the functions are folded.
In the future we will explore specializing for multiple values of NumThreads and NumTeams.
Depends on D106390
Reviewed By: jdoerfert, JonChesterfield
Differential Revision: https://reviews.llvm.org/D106033
This reapplies commit cbb709e251 and
includes the use of the lookup method instead of operator[] to avoid
accidentally setting (empty) simplification callbacks.
This reverts commit aa27430a62.
AAValueSimplify, AAValueConstantRange, and AAPotentialValues all look at
the IR by default. If queried for a IR position which has a
simplification callback we should either look at the callback return, or
give up. We do the latter for now.
The current JumpThreading pass does not jump thread loops since it can
result in irreducible control flow that harms other optimizations. This
prevents switch statements inside a loop from being optimized to use
unconditional branches.
This code pattern occurs in the core_state_transition function of
Coremark. The state machine can be implemented manually with goto
statements resulting in a large runtime improvement, and this transform
makes the switch implementation match the goto version in performance.
This patch specifically targets switch statements inside a loop that
have the opportunity to be threaded. Once it identifies an opportunity,
it creates new paths that branch directly to the correct code block.
For example, the left CFG could be transformed to the right CFG:
```
sw.bb sw.bb
/ | \ / | \
case1 case2 case3 case1 case2 case3
\ | / / | \
latch.bb latch.2 latch.3 latch.1
br sw.bb / | \
sw.bb.2 sw.bb.3 sw.bb.1
br case2 br case3 br case1
```
Co-author: Justin Kreiner @jkreiner
Co-author: Ehsan Amiri @amehsan
Reviewed By: SjoerdMeijer
Differential Revision: https://reviews.llvm.org/D99205
Eliminating loads/stores in the device code is worth the extra effort,
especially for the new device runtime.
At the same time we do not compute AAExecutionDomain for non-device code
anymore, there is no point.
Differential Revision: https://reviews.llvm.org/D106845
When we simplify at least one operand in the Attributor simplification
we can use the InstSimplify to work on the simplified operands. This
allows us to avoid duplication of the logic.
Depends on D106189
Differential Revision: https://reviews.llvm.org/D106190
This change slightly relaxed the current ICP threshold in top-down inliner, specifically always allow one ICP for it. It shows some perf improvements on SPEC and our internal benchmarks. Also renamed the previous flag. We can also try to turn off PGO ICP in the future.
Reviewed By: wenlei, hoy, wmi
Differential Revision: https://reviews.llvm.org/D106588
D106185 allows us to determine if a store is needed easily. Using that
knowledge we can start to delete dead stores.
In AAIsDead we now track more state as an instruction can be dead (= the
old optimisitc state) or just "removable". A store instruction can be
removable while being very much alive, e.g., if it stores a constant
into an alloca or internal global. If we would pretend it was dead
instead of only removablewe we would ignore it when we determine what
values a load can see, so that is not what we want.
Differential Revision: https://reviews.llvm.org/D106188
This patch introduces `getPotentialCopiesOfStoredValue` which uses
AAPointerInfo to determine all "aliases" or "potential copies" of a
value that is stored into memory. This operation can fail but if it
succeeds it means we can visit all "uses" of a value even if it is
temporarily stored in memory.
There are two users for the function:
1) `Attributor::checkForAllUses` which will now ignore the value use
in a store if all "potential copies" can be identified and instead
be visited. This allows various AAs, including AAPointerInfo
itself, to look through memory.
2) `AANoCapture` which uses a custom use tracking through the
CaptureTracker interface and therefore needs to be thought
explicitly.
Differential Revision: https://reviews.llvm.org/D106185
Similar to D105787, this patch tries to fold `__kmpc_parallel_level` if possible.
Note that `__kmpc_parallel_level` doesn't take activeness into consideration,
based on current `deviceRTLs`, its return value can be such as 0, 1, 2, instead
of 0, 129, 130, etc. that also indicate activeness.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D106154
While rewriteDeviceCodeStateMachine should probably be folded into
buildCustomStateMachine, we at least need the optimization to happen.
This was not reliably the case in the CGSCC pass but in the Module pass
it seems to work reliably.
This also ports a test to the new kernel encoding (target_init/deinit),
and makes sure we cannot run the kernel in SPMD mode.
Differential Revision: https://reviews.llvm.org/D106345
Wenlei He