Rename the function to reflect its correct behavior and to be consistent
with `Module::getOrInsertFunction`. This is also in preparation of
adding a new `Intrinsic::getDeclaration` that will have behavior similar
to `Module::getFunction` (i.e, just lookup, no creation).
An atomic fadd instruction like this should return %x:
; value at %ptr is %x
%r = atomicrmw fadd ptr %ptr, float %y
After atomic optimization, if %y is uniform, the result is calculated
as %r = %x + * %y * +0.0. This has a couple of problems:
1. If %y is Inf or NaN, this will return NaN instead of %x.
2. If %x is -0.0 and %y is positive, this will return +0.0 instead of
-0.0.
Avoid these problems by disabling the "%y is uniform" path if there are
any uses of the result.
atomicrmw fmax/fmin perform the same operation as llvm.maxnum/minnum
which return the other operand if one operand is nan. This means that,
in the presence of nan arguments, +/- inf is not an identity for these
operations but nan is (at least if you don't care about nan payloads).
These are incremental changes over #89217 , with core logic being the
same. This patch along with #89217 and #91190 should get us ready to enable 64
bit optimizations in atomic optimizer.
This patch is intended to be the first of a series with end goal to
adapt atomic optimizer pass to support i64 and f64 operations (along
with removing all unnecessary bitcasts). This legalizes 64 bit readlane,
writelane and readfirstlane ops pre-ISel
---------
Co-authored-by: vikramRH <vikhegde@amd.com>
Uses the new InsertPosition class (added in #94226) to simplify some of
the IRBuilder interface, and removes the need to pass a BasicBlock
alongside a BasicBlock::iterator, using the fact that we can now get the
parent basic block from the iterator even if it points to the sentinel.
This patch removes the BasicBlock argument from each constructor or call
to setInsertPoint.
This has no functional effect, but later on as we look to remove the
`Instruction *InsertBefore` argument from instruction-creation
(discussed
[here](https://discourse.llvm.org/t/psa-instruction-constructors-changing-to-iterator-only-insertion/77845)),
this will simplify the process by allowing us to deprecate the
InsertPosition constructor directly and catch all the cases where we use
instructions rather than iterators.
Use the form of CreateIntrinsic that takes an explicit return type and
works out the mangling based on that and the types of the arguments. The
advantage is that this still works if intrinsics are changed to have
type mangling, e.g. if readlane/readfirstlane/writelane are changed to
work on any type.
We take the terminator from EntryBB and put it in ComputeEnd. Make sure
we also move the DT edges, we previously only did it assuming a
non-conditional branch.
Fixes SWDEV-453943
Presently the atomic optimizer supports only 32-bit operations. Plan is
to extend the atomic optimizer for 64-bit operations for compute and
graphics. This patch extends support for double type for `uniform
values` only. Going forward, will extend the support for divergent
values. Adding support for divergent values requires
extending/legalizing readfirstlane, readlane, writelane, etc ops for
64-bit operations to avoid `bitcast` noise that we have currently.
---------
Authored-by: Pravin Jagtap <Pravin.Jagtap@amd.com>
[D156301](https://reviews.llvm.org/D156301) introduced atomic
optimizations for FAdd/FSub. For FSub, reduction/scan needs to be
performed using add operation (`not sub`) and memory location will be
updated by reduced value using atomic sub later by only one lane.
---------
Authored-by: Pravin Jagtap <Pravin.Jagtap@amd.com>
Reduction and Scan are implemented using `Iterative`
and `DPP` strategy for `float` type.
Reviewed By: arsenm, #amdgpu
Differential Revision: https://reviews.llvm.org/D156301
Atomic optimizer is turned on by default through D152649. This patch
removes the usage of old command line option amdgpu-atomic-optimizations
and transfer the responsibility to `amdgpu-atomic-optimizer-strategy`.
We can safely remove old option when LLPC remove its all usage.
Reviewed By: foad, arsenm, #amdgpu, cdevadas
Differential Revision: https://reviews.llvm.org/D153007
AMDGPUAtomicOptimizer updates the dominator tree whenever
it modified the control flow. Therefore preserving the
analysis similar to legacy PM.
Reviewed By: arsenm, yassingh, #amdgpu
Differential Revision: https://reviews.llvm.org/D153349
Verifying dominator tree is expensive using intra-pass
asserts. Asserts added during D147408 are
increasing the build time of libc significantly. This change
does the verification after the atomic optimizer pass
and should fix the regression reported in D153232.
Reviewed By: arsenm, #amdgpu
Differential Revision: https://reviews.llvm.org/D153261
This patch provides an alternative implementation to DPP for Scan Computations.
An alternative implementation iterates over all active lanes of Wavefront
using llvm.cttz and performs the following steps:
1. Read the value that needs to be atomically incremented using
llvm.amdgcn.readlane intrinsic
2. Accumulate the result.
3. Update the scan result using llvm.amdgcn.writelane intrinsic
if intermediate scan results are needed later in the kernel.
Reviewed By: arsenm, cdevadas
Differential Revision: https://reviews.llvm.org/D147408
In order to enable the LLVM frontend to better analyze buffer
operations (and to potentially enable more precise analyses on the
backend), define versions of the raw and structured buffer intrinsics
that use `ptr addrspace(8)` instead of `<4 x i32>` to represent their
rsrc arguments.
The new intrinsics are named by replacing `buffer.` with `buffer.ptr`.
One advantage to these intrinsic definitions is that, instead of
specifying that a buffer load/store will read/write some memory, we
can indicate that the memory read or written will be based on the
pointer argument. This means that, for example, a read from a
`noalias` buffer can be pulled out of a loop that is modifying a
distinct buffer.
In the future, we will define custom PseudoSourceValues that will
allow us to package up the (buffer, index, offset) triples that buffer
intrinsics contain and allow for more precise backend analysis.
This work also enables creating address space 7, which represents
manipulation of raw buffers using native LLVM load and store
instructions.
Where tests simply used a buffer intrinsic while testing some other
code path (such as the tests for VGPR spills), they have been updated
to use the new intrinsic form. Tests that are "about" buffer
intrinsics (for instance, those that ensure that they codegen as
expected) have been duplicated, either within existing files or into
new ones.
Depends on D145441
Reviewed By: arsenm, #amdgpu
Differential Revision: https://reviews.llvm.org/D147547
The method is marked for deprecation. Delete the method and move all of
its consumers to use the DomTreeUpdater version.
Reviewed By: foad
Differential Revision: https://reviews.llvm.org/D149428
Adds & uses a new `isDivergentUse` API in UA.
UniformityAnalysis now requires CycleInfo as well as the new temporal divergence API can query it.
-----
Original patch that adds `isDivergentUse` by @sameerds
The user of a temporally divergent value is marked as divergent in the
uniformity analysis. But the same user may also have been marked divergent for
other reasons, thus losing this information about temporal divergence. But some
clients need to specificly check for temporal divergence. This change restores
such an API, that already existed in DivergenceAnalysis.
Reviewed By: sameerds, foad
Differential Revision: https://reviews.llvm.org/D146018
Compared to permlane16, permlane64 has no BC input because it has no
boundary conditions, no fi input because the instruction acts as if FI
were always enabled, and no OLD input because it always writes to every
active lane.
Also use the new intrinsic in the atomic optimizer pass.
Differential Revision: https://reviews.llvm.org/D127662
If the result of an atomic operation is not used then it can be more
efficient to build a reduction across all lanes instead of a scan. Do
this for GFX10, where the permlanex16 instruction makes it viable. For
wave64 this saves a couple of dpp operations. For wave32 it saves one
readlane (which are generally bad for performance) and one dpp
operation.
Differential Revision: https://reviews.llvm.org/D98953
* Introduce the new intrinsic amdgcn_strict_wwm
* Deprecate the old intrinsic amdgcn_wwm
The change is done for consistency as the "strict"
prefix will become an important, distinguishing factor
between amdgcn_wqm and amdgcn_strictwqm in the future.
The "strict" prefix indicates that inactive lanes do not
take part in control flow, specifically an inactive lane
enabled by a strict mode will always be enabled irrespective
of control flow decisions.
The amdgcn_wwm will be removed, but doing so in two steps
gives users time to switch to the new name at their own pace.
Reviewed By: critson
Differential Revision: https://reviews.llvm.org/D96257
Check if operand of mul is constant value of one for certain atomic
instructions in order to avoid making unnecessary instructions when
-amdgpu-atomic-optimizer is present.
Differential Revision: https://reviews.llvm.org/D88315
Add a new llvm.amdgcn.ballot intrinsic modeled on the ballot function
in GLSL and other shader languages. It returns a bitfield containing the
result of its boolean argument in all active lanes, and zero in all
inactive lanes.
This is intended to replace the existing llvm.amdgcn.icmp and
llvm.amdgcn.fcmp intrinsics after a suitable transition period.
Use the new intrinsic in the atomic optimizer pass.
Differential Revision: https://reviews.llvm.org/D65088
This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.
I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
recompiles touches affected_files header
342380 95 3604 llvm/include/llvm/ADT/STLExtras.h
314730 234 1345 llvm/include/llvm/InitializePasses.h
307036 118 2602 llvm/include/llvm/ADT/APInt.h
213049 59 3611 llvm/include/llvm/Support/MathExtras.h
170422 47 3626 llvm/include/llvm/Support/Compiler.h
162225 45 3605 llvm/include/llvm/ADT/Optional.h
158319 63 2513 llvm/include/llvm/ADT/Triple.h
140322 39 3598 llvm/include/llvm/ADT/StringRef.h
137647 59 2333 llvm/include/llvm/Support/Error.h
131619 73 1803 llvm/include/llvm/Support/FileSystem.h
Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.
Reviewers: bkramer, asbirlea, bollu, jdoerfert
Differential Revision: https://reviews.llvm.org/D70211
Summary:
Add support for gfx10, where all DPP operations are confined to work
within a single row of 16 lanes, and wave32.
Reviewers: arsenm, sheredom, critson, rampitec
Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, t-tye, hiraditya, jfb, dstuttard, tpr, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65644
llvm-svn: 369745
Summary:
The existing isDivergent(Value) methods query whether a value is
divergent at its definition. However even if a value is uniform at its
definition, a use of it in another basic block can be divergent because
of divergent control flow between the def and the use.
This patch adds new isDivergent(Use) methods to DivergenceAnalysis,
LegacyDivergenceAnalysis and GPUDivergenceAnalysis.
This might allow D63953 or other similar workarounds to be removed.
Reviewers: alex-t, nhaehnle, arsenm, rtaylor, rampitec, simoll, jingyue
Reviewed By: nhaehnle
Subscribers: jfb, jvesely, wdng, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65141
llvm-svn: 367218
Summary:
In the atomic optimizer, save doing a bunch of work and generating a
bunch of dead IR in the fairly common case where the result of an
atomic op (i.e. the value that was in memory before the atomic op was
performed) is not used. NFC.
Reviewers: arsenm, dstuttard, tpr
Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, t-tye, hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64981
llvm-svn: 366667
