Same dangling probes are redundant since they all have the same semantic that is to rely on the counts inference tool to get reasonable count for the same original block. Therefore, there's no need to keep multiple copies of them. I've seen jump threading created tons of redundant dangling probes that slowed down the compiler dramatically. Other optimization passes can also result in redundant probes though without an observed impact so far.
This change removes block-wise redundant dangling probes specifically introduced by jump threading. To support removing redundant dangling probes caused by all other passes, a final function-wise deduplication is also added.
An 18% size win of the .pseudo_probe section was seen for SPEC2017. No performance difference was observed.
Differential Revision: https://reviews.llvm.org/D97482
This change fixes a couple places where the pseudo probe intrinsic blocks optimizations because they are not naturally removable. To unblock those optimizations, the blocking pseudo probes are moved out of the original blocks and tagged dangling, instead of allowing pseudo probes to be literally removed. The reason is that when the original block is removed, we won't be able to sample it. Instead of assigning it a zero weight, moving all its pseudo probes into another block and marking them dangling should allow the counts inference a chance to assign them a more reasonable weight. We have not seen counts quality degradation from our experiments.
The optimizations being unblocked are:
1. Removing conditional probes for if-converted branches. Conditional probes are tagged dangling when their homing branch arms are folded so that they will not be over-counted.
2. Unblocking jump threading from removing empty blocks. Pseudo probe prevents jump threading from removing logically empty blocks that only has one unconditional jump instructions.
3. Unblocking SimplifyCFG and MIR tail duplicate to thread empty blocks and blocks with redundant branch checks.
Since dangling probes are logically deleted, they should not consume any samples in LTO postLink. This can be achieved by setting their distribution factors to zero when dangled.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D97481
Dangling probes are the probes associated to an empty block. This usually happens when all real instructions are optimized away from the block. There is a problem with dangling probes during the offline counts processing. The way the sample profiler works is that samples collected on the first physical instruction following a probe will be counted towards the probe. This logically equals to treating the instruction next to a probe as if it is from the same block of the probe. In the dangling probe case, the real instruction following a dangling probe actually starts a new block, and samples collected on the new block may cause issues when counted towards the empty block.
To mitigate this issue, we first try to move around a dangling probe inside its owning block. If there are still native instructions preceding the probe in the same block, we can then use them as a place holder to collect samples for the probe. A pass is added to walk each block backwards looking for probes not followed by any real instruction and moving them before the first real instruction. This is done right before the object emission.
If we are unlucky to find such in-block preceding instructions for a probe, the solution we are taking is to tag such probe as dangling so that the samples reported for them will not be trusted by the compiler. We leave it up to the counts inference algorithm to get such probes a reasonable count. The number `UINT64_MAX` is used to mark sample count as collected for a dangling probe.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D95962
Implements parts of:
- P0898R3 Standard Library Concepts
- P1754 Rename concepts to standard_case for C++20, while we still can
Depends on D96660
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D96742
We don't need a bool and an enum to express the three options we
currently have. This makes the interface nicer and much easier to
use optional dependencies. Also avoids mistakes where the bool is
false and enum ignored.
This is an attempt to improve handling of partial overlaps in case of unaligned begin\end.
Existing implementation just bails out if it encounters such cases. Even when it doesn't I believe existing code checking alignment constraints is not quite correct. It tries to ensure alignment of the "later" start/end offset while should be preserving relative alignment between earlier and later start/end.
The idea behind the change is simple. When start/end is not aligned as we wish instead of bailing out let's adjust it as necessary to get desired alignment.
I'll update with performance results as measured by the test-suite...it's still running...
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D93530
Add clspv as a new target for libclc. clspv is an open-source compiler that compiles OpenCL C to Vulkan SPIR-V. Compiles for the spir target.
The clspv target differs from the the spirv target in the following ways:
* fma is modified to use uint2 instead of ulong for mantissas. This results in lower performance fma, but provides a implementation that can be used on more Vulkan devices where 64-bit integer support is less common.
* Use of a software implementation of nextafter because the generic implementation depends on nextafter being a defined builtin function for which clspv has no definition.
* Full optimization of the library (-O3) and no conversion to SPIR-V
This library is close to what would be produced by running opt -O3 < builtins.opt.spirv-mesa3d-.bc > builtins.opt.clspv--.bc and continuing the build from that point.
Reviewer: jvesely
Differential Revision: https://reviews.llvm.org/D94013
This knob is useful for downstream users who want that some of their
libc functions to not be intercepted.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D97740
Implements parts of:
- P0898R3 Standard Library Concepts
- P1754 Rename concepts to standard_case for C++20, while we still can
Depends on D96660
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D96683
statepoint intrinsic can be used in invoke context,
so it should be handled in visitCallBase to cover both call and invoke.
Reviewers: reames, dantrushin
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D97833
Add calls into LanguageRuntime when finding the unwind method to
use out of the 0th (currently executing) stack frame.
Allow for the LanguageRuntimes to indicate if this stack frames
should be treated like a zeroth-frame -- symbolication should be
done based on the saved pc address, not decremented like normal ABI
function calls.
Add methods to RegisterContext and StackFrame to get a pc value
suitable for symbolication, to reduce the number of places in lldb
where we decrement the saved pc values before symbolication.
<rdar://problem/70398009>
Differential Revision: https://reviews.llvm.org/D97644
This is just a shorter synonym for `__identity<T>::type`.
Use it consistently throughout, where possible.
There is still some metaprogramming in <memory> and <variant>
where `__identity` is being used _without_ immediately calling
`::type` on it; but this is the unusual case, and it will become
even less usual as we start deliberately protecting certain types
against deduction (e.g. D97742).
Differential Revision: https://reviews.llvm.org/D97862
Implements parts of:
- P0898R3 Standard Library Concepts
- P1754 Rename concepts to standard_case for C++20, while we still can
Depends on D96657
Reviewed By: ldionne, Mordante, #libc
Differential Revision: https://reviews.llvm.org/D96660
Found with exhaustive testing, it is possible that a while loop
appears in between chainable for loops. As long as we don't
scalarize reductions in while loops, this means we need to
terminate the chain at the while. This also refactors the
reduction code into more readable helper methods.
Reviewed By: bixia
Differential Revision: https://reviews.llvm.org/D97886
This patch is an update to LangRef by describing lifetime intrinsics' behavior
by following the description of MIR's LIFETIME_START/LIFETIME_END markers
at StackColoring.cpp (eb44682d67/llvm/lib/CodeGen/StackColoring.cpp (L163)) and the discussion in llvm-dev.
In order to explicitly define the meaning of an object lifetime, I added 'Object Lifetime' subsection.
Reviewed By: nlopes
Differential Revision: https://reviews.llvm.org/D94002
The support for attributes closely maps that of Types (basically 1-1) given that Attributes are defined in exactly the same way as Types. All of the current ODS TypeDef classes get an Attr equivalent. The generation of the attribute classes themselves share the same generator as types.
Differential Revision: https://reviews.llvm.org/D97589
Use that to print the diagnostic in SemaChecking instead of
listing all of the builtins in a switch.
With the required features, IR generation will also be able
to error on this. Checking this here allows us to have a RISCV
focused error message.
Reviewed By: HsiangKai
Differential Revision: https://reviews.llvm.org/D97826
IR symbol table does not parse inline asm. A symbol only referenced by inline
asm is not in the IR symbol table, so LTO does not know that the definition (in
another translation unit) is referenced and may internalize it, even if that
definition has `__attribute__((used))` (which lowers to `llvm.compiler.used` on
ELF targets since D97446).
```
// cabac.c
__attribute__((used)) const uint8_t ff_h264_cabac_tables[...] = {...};
// h264_cabac.c
asm("lea ff_h264_cabac_tables(%rip), %0" : ...);
```
`__attribute__((used))` is the recommended way to tell the compiler there may
be inline asm references, so the usage is perfectly fine. This patch
conservatively sets the `FB_used` bit on `llvm.compiler.used` symbols to work
around the IR symbol table limitation. Note: before D97446, Clang never emitted
symbols in the `llvm.compiler.used` list, so this change does not punish any
Clang emitted global object.
Without the patch, `ff_h264_cabac_tables` may be assigned to a non-external
partition and get internalized. Then we will get a linker error because the
`cabac.c` definition is not exposed.
Differential Revision: https://reviews.llvm.org/D97755
This better matches the actual IR concept that is being modeled, and is consistent with how the rest of PDL is structured.
Differential Revision: https://reviews.llvm.org/D95718
This type represents a range of positional values. It will be used in followup revisions to add support for variadic constructs to PDL, such as operand and result ranges.
Differential Revision: https://reviews.llvm.org/D95717
See pr46990(https://bugs.llvm.org/show_bug.cgi?id=46990). LICM should not sink store instructions to loop exit blocks which cross coro.suspend intrinsics. This breaks semantic of coro.suspend intrinsic which return to caller directly. Also this leads to use-after-free if the coroutine is freed before control returns to the caller in multithread environment.
This patch disable promotion by check whether loop contains coro.suspend intrinsics.
This is a resubmit of D86190.
Disabling LICM for loops with coroutine suspension is a better option not only for correctness purpose but also for performance purpose.
In most cases LICM sinks memory operations. In the case of coroutine, sinking memory operation out of the loop does not improve performance since coroutien needs to get data from the frame anyway. In fact LICM would hurt coroutine performance since it adds more entries to the frame.
Differential Revision: https://reviews.llvm.org/D96928
The compiler needs to mark register $x0 as live in for the following case.
$x1 = ADDXri $sp, 16, 0
BL @spam, csr_darwin_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit $x0, implicit killed $x1, implicit-def $sp, implicit-def dead $x0
Reviewed By: paquette
Differential Revision: https://reviews.llvm.org/D95267
As a preparation step for fast8 support, we need to update the tests
to pass in both modes. That requires generalizing the shadow width
and remove any hard coded references that assume it's always 2 bytes.
Reviewed By: stephan.yichao.zhao
Differential Revision: https://reviews.llvm.org/D97884
The current implementation of Value involves a pointer int pair with several different kinds of owners, i.e. BlockArgumentImpl*, Operation *, TrailingOpResult*. This design arose from the desire to save memory overhead for operations that have a very small number of results (generally 0-2). There are, unfortunately, many problematic aspects of the current implementation that make Values difficult to work with or just inefficient.
Operation result types are stored as a separate array on the Operation. This is very inefficient for many reasons: we use TupleType for multiple results, which can lead to huge amounts of memory usage if multi-result operations change types frequently(they do). It also means that simple methods like Value::getType/Value::setType now require complex logic to get to the desired type.
Value only has one pointer bit free, severely limiting the ability to use it in things like PointerUnion/PointerIntPair. Given that we store the kind of a Value along with the "owner" pointer, we only leave one bit free for users of Value. This creates situations where we end up nesting PointerUnions to be able to use Value in one.
As noted above, most of the methods in Value need to branch on at least 3 different cases which is both inefficient, possibly error prone, and verbose. The current storage of results also creates problems for utilities like ValueRange/TypeRange, which want to efficiently store base pointers to ranges (of which Operation* isn't really useful as one).
This revision greatly simplifies the implementation of Value by the introduction of a new ValueImpl class. This class contains all of the state shared between all of the various derived value classes; i.e. the use list, the type, and the kind. This shared implementation class provides several large benefits:
* Most of the methods on value are now branchless, and often one-liners.
* The "kind" of the value is now stored in ValueImpl instead of Value
This frees up all of Value's pointer bits, allowing for users to take full advantage of PointerUnion/PointerIntPair/etc. It also allows for storing more operation results as "inline", 6 now instead of 2, freeing up 1 word per new inline result.
* Operation result types are now stored in the result, instead of a side array
This drops the size of zero-result operations by 1 word. It also removes the memory crushing use of TupleType for operations results (which could lead up to hundreds of megabytes of "dead" TupleTypes in the context). This also allowed restructured ValueRange, making it simpler and one word smaller.
This revision does come with two conceptual downsides:
* Operation::getResultTypes no longer returns an ArrayRef<Type>
This conceptually makes some usages slower, as the iterator increment is slightly more complex.
* OpResult::getOwner is slightly more expensive, as it now requires a little bit of arithmetic
From profiling, neither of the conceptual downsides have resulted in any perceivable hit to performance. Given the advantages of the new design, most compiles are slightly faster.
Differential Revision: https://reviews.llvm.org/D97804
This is a mess, but this is hopefully no-functional-change.
The 'Prev' descriptor is only used for min/max recurrences
or when starting a match from a phi, so it should not be a
factor when propagating FMF for fmul/fadd.
The API is confusing (and should be reduced in subsequent steps)
because the "UnsafeAlgebraInst" appears to actually be a placeholder
for a recurrence that does NOT have FMF, but we still want to
treat it as reassociative.
Apple back-deployment testing is currently failing because Green Dragon
is down. To avoid stalling the whole CI pipeline because of that, I am
temporarily disabling those jobs until Green Dragon is back, or even
better we have found a different way to store those small artifacts.
The SubTensorInsertOp has a requirement that dest type and result
type match. Just folding the tensor.cast operation violates this and
creates verification errors during canonicalization. Also fix other
canonicalization methods that werent inserting casts properly.
Differential Revision: https://reviews.llvm.org/D97800
Make sure we preserve info about passed arguments as implicit uses, to
make sure later passes still have access to this information.
This fixes a mis-compile where the machine-combiner would pick an
incorrect free register.
This reverts commit 900f076113 and attempts an actual fix: All failing tests for llvm-jitlink use the `-noexec` flag. The inputs they operate on are not meant for execution on the host system. Looking e.g. at the MachO_test_harness_harnesss.s test, llvm-mc generates input machine code with "x86_64-apple-macosx10.9".
My previous attempt in bbdb4c8c9b disabled the debug support plugin for Windows targets, but what we would actually want is to disable it on Windows HOSTS.
With the new patch here, I don't do exactly that, but instead follow the approach for the EH frame plugin and include the `-noexec` flag in the condition. It should have the desired effect when it comes to the test suite. It appears a little workaround'ish, but should work reliably for now. I will discuss the issue with Lang and see if we can do better. Thanks @thakis again for the temporary fix.
unsigned variable 'IntNo' has been declared but not been defined inside function
EmitWebAssemblyBuiltinExpr().
static code analysis tool complains about uninitialized variable "IntNo" since
this enters to default branch without setting any intrinsics and calls Function
*Callee = CGM.getIntrinsic(IntNo).
This patch fixes the problem by adding default cases in switch statements.
We previously defaulted to x86_64 and an unknown platform, which was fine when
we only supported one arch and did no platform checks, but that will no longer
be true going ahead. Therefore, we should require those flags to be specified
whenever the linker is invoked.
Note that LLD-ELF and ld64 both infer the arch from their input object files,
but the usefulness of that is questionable since clang will always specify these
flags, and most of the time `lld` will be invoked via clang.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D97799
The option-iterating loop should be reserved for options whose command-line
order is important. I think LLD-ELF follows a similar design.
Reviewed By: #lld-macho, smeenai
Differential Revision: https://reviews.llvm.org/D97797
Hongtao Yu