Allow using atomicrmw fadd, fsub, fmin, and fmax with vectors of
floating-point type. AMDGPU supports atomic fadd for <2 x half> and <2 x
bfloat> on some targets and address spaces.
Note this only supports the proper floating-point operations; float
vector typed xchg is still not supported. cmpxchg still only supports
integers, so this inserts bitcasts for the loop expansion.
I have support for fp vector typed xchg, and vector of int/ptr
separately implemented but I don't have an immediate need for those
beyond feature consistency.
The AtomicExpand pass was lowering function calls with the strictfp
attribute to sequences that included function calls incorrectly lacking
the attribute. This patch corrects that.
The pass now also emits the correct constrained fp call instead of
normal FP instructions when in a function with the strictfp attribute.
Test changes verified with D146845.
This will result in larger atomic operations getting expanded to
`__atomic_*` libcalls via AtomicExpandPass, which matches what Clang
already does in the frontend.
While AMDGPU currently disables the use of all libcalls, I've changed it
to instead disable all of them _except_ the atomic ones. Those are
already be emitted by the Clang frontend, and enabling them in the
backend allows the same behavior there.
There are many tests that specify a target triple/CPU flags but no
DataLayout which can lead to IR being generated that has unusual
behaviour. This commit attempts to use the default DataLayout based
on the relevant flags if there is no explicit override on the command
line or in the IR file.
One thing that is not currently possible to differentiate from a missing
datalayout `target datalayout = ""` in the IR file since the current
APIs don't allow detecting this case. If it is considered useful to
support this case (instead of passing "-data-layout=" on the command
line), I can change IR parsers to track whether they have seen such a
directive and change the callback type.
Differential Revision: https://reviews.llvm.org/D141060
On AIX, a libatomic supporting inline quadword atomic operations has been released, so that compatibility is not an issue now, we can enable quadword atomics by default.
Reviewed By: #powerpc, nemanjai
Differential Revision: https://reviews.llvm.org/D151312
This reverts commit 593797ab9bedca6e9b0b7a9ed0589cf76023ab00.
I didn't realize that there was already a fix for the broken tests fd2254b7358d0f78a79784688bd8012c1a52b9cf.
Ideally the normal fadd/fmin/fmax this was creating would fail the verifier.
It's probably also necessary to force off FP exception handlers in the cmpxchg
loop but we don't have a generic way to do that now.
Note strictfp builder is broken in the minnum/maxnum case
https://reviews.llvm.org/D154993
This is a follow-up to b71edfaa4ec3c998aadb35255ce2f60bba2940b0
since I forgot the lit.local.cfg files in that one.
Reformatting is done with `black`.
If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: barannikov88, kwk
Differential Revision: https://reviews.llvm.org/D150762
Re-land D145441 with data layout upgrade code fixed to not break OpenMP.
This reverts commit 3f2fbe92d0f40bcb46db7636db9ec3f7e7899b27.
Differential Revision: https://reviews.llvm.org/D149776
Per discussion at
https://discourse.llvm.org/t/representing-buffer-descriptors-in-the-amdgpu-target-call-for-suggestions/68798,
we define two new address spaces for AMDGCN targets.
The first is address space 7, a non-integral address space (which was
already in the data layout) that has 160-bit pointers (which are
256-bit aligned) and uses a 32-bit offset. These pointers combine a
128-bit buffer descriptor and a 32-bit offset, and will be usable with
normal LLVM operations (load, store, GEP). However, they will be
rewritten out of existence before code generation.
The second of these is address space 8, the address space for "buffer
resources". These will be used to represent the resource arguments to
buffer instructions, and new buffer intrinsics will be defined that
take them instead of <4 x i32> as resource arguments. ptr
addrspace(8). These pointers are 128-bits long (with the same
alignment). They must not be used as the arguments to getelementptr or
otherwise used in address computations, since they can have
arbitrarily complex inherent addressing semantics that can't be
represented in LLVM. Even though, like their address space 7 cousins,
these pointers have deterministic ptrtoint/inttoptr semantics, they
are defined to be non-integral in order to prevent optimizations that
rely on pointers being a [0, [addr_max]] value from applying to them.
Future work includes:
- Defining new buffer intrinsics that take ptr addrspace(8) resources.
- A late rewrite to turn address space 7 operations into buffer
intrinsics and offset computations.
This commit also updates the "fallback address space" for buffer
intrinsics to the buffer resource, and updates the alias analysis
table.
Depends on D143437
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D145441
These are essentially add/sub 1 with a clamping value.
AMDGPU has instructions for these. CUDA/HIP expose these as
atomicInc/atomicDec. Currently we use target intrinsics for these,
but those do no carry the ordering and syncscope. Add these to
atomicrmw so we can carry these and benefit from the regular
legalization processes.
Two lit tests were found running something like this:
opt -O<n> -pass-locked-to-legacy-PM ...
The expand-atomicrmw-xchg-fp.ll seem to have used -O1 just to ensure
that the -atomic-expand pass were thinking that it wasn't running at
O0 level. Same thing can be ensured by using the -codegen-opt-level=1
option, making it possible to avoid using O1 in that test case.
In the vector-reductions-expanded.ll test case it was possible to
split the RUN line into using two opt invocations. First running
"opt -O2" using the new PM, and then running "opt -expand-reductions"
using the legacy PM.
I think that given this patch we get closer to removing code related
to 'AddOptimizationPasses' in opt.cpp.
Differential Revision: https://reviews.llvm.org/D137626
The 32-bit floating-point atomic add instructions on AMDGPUs does not support a
"flat" or "generic" address space. So, if the address space cannot be determined
statically, the AMDGPU backend will fall back to a CAS loop (which does support
"flat" addressing). Instead, this patch emits runtime address-space checks to
allow native FP atomic add instructions for global and LDS memory (and non-atomic
FP add instructions for private/scratch memory).
In order to do that, this patch introduces a new interface function
`emitExpandAtomicRMW`. It is expected to be called when a common atomic expand
doesn't work for a specific target, such as the case we discussed here.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D129690
This removes the ptrtoint from the load's pointer operand, although we
can't entirely eliminate these to get the LSB shift. In a future
patch, this will avoid ptrtoint in the case where the atomic is
overaligned to the word size.
Use same atomicrmw fadd expansion rules for gfx908, gfx940 and gfx11
as for gfx90a. Add missing globalisel legalizer support for flat
atomicrmw fadd f32 on gfx940 and gfx11.
Isel support for gfx11 will be added in D130579.
Differential Revision: https://reviews.llvm.org/D131560
Precommit for D130579 that will remove manual selection and use
patterns from td files. Tests are grouped based on target features.
All patterns have rtn and no-rtn versions.
buffer atomics patterns are selected based on the intrinsic used
(raw or struct) and the offset operand (imm or vgpr):
_offset raw with imm offset
_offen raw with vgpr offset (or large imm offset)
_idxen struct with imm offset
_bothen struct with vgpr offset (or large imm offset)
global and flat atomics are selected via intrinsic or the atomicrmw fadd.
atomicrmw tests have amdgpu-unsafe-fp-atomics=true and non-system scope
since they get expanded otherwise. atomicrmw fadd does not support vector
type, test float and double.
global atomics patterns are selected based on address type via (global or
flat) intrinsic or atomicrmw fadd with global address(addrspace(1)*).
'no suffix' vgpr addrspace(1)* address
_saddr sgpr addrspace(1)* address
flat atomics patterns are selected via (flat)intrinsic or atomicrmw fadd
with flat address (* - address space 0).
Differential Revision: https://reviews.llvm.org/D131561
When expanding IR atomics to target-specific atomics, copy all
!pcsections Metadata to expanded atomics automatically.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D130885
IIUC, the conversion part is not part of atomic operations and fences should be put around converted atomic operations.
This also fixes atomic load of floating point values which requires fence on PowerPC.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D127609
