Insert waitcnts for loads and atomics before stores with system scope.
Scope is field in instruction encoding and corresponds to desired
coherence level in cache hierarchy.
Intrinsic stores can set scope in cache policy operand.
If volatile keyword is used on generic stores memory legalizer will set
scope to system. Generic stores, by default, get lowest scope level.
Waitcnts are not required if it is guaranteed that memory is cached.
For example vulkan shaders can guarantee this.
TODO: implement flag for frontends to give us a hint not to insert
waits.
Expecting vulkan flag to be implemented as vulkan:private MMRA.
Update SIMemoryLegalizer and SIInsertWaitcnts to use separate wait
instructions per counter (e.g. S_WAIT_LOADCNT) and split VMCNT into
separate LOADCNT, SAMPLECNT and BVHCNT counters.
Memory models for gfx90a and gfx940 do not require buffer_wbl2
before the fence for acquire ordering, but we do insert the full
release.
Fixes: SWDEV-386785
Differential Revision: https://reviews.llvm.org/D145524
value() has undesired exception checking semantics and calls
__throw_bad_optional_access in libc++. Moreover, the API is unavailable without
_LIBCPP_NO_EXCEPTIONS on older Mach-O platforms (see
_LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS).
This fixes clang.
C++17 allows us to call constructors pair and tuple instead of helper
functions make_pair and make_tuple.
Differential Revision: https://reviews.llvm.org/D139828
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
In GFX10 dlc controlled L1 cache bypass. In GFX11 it has been repurposed
to control MALL NOALLOC, and glc controls L1 as well as L0 cache bypass.
Update the documentation and SIMemoryLegalizer accordingly. Set dlc for
nontemporal and volatile accesses.
Differential Revision: https://reviews.llvm.org/D127405
This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169
Attempt to further document the intended cache policies requested
by different combinations of GLC, SLC and DLC bits.
GFX10 non-temporal stores are updated to set GLC.
Reviewed By: t-tye
Differential Revision: https://reviews.llvm.org/D114351
C++20 no longer requires the failure memory ordering to be no stronger than the
success memory ordering. Adjust assert in AMD GPU SIMemoryLegalizer, and merge
instruction memory orderings
Add common operation to merge memory orders that allows non strict memory
orderings to be combined. Use it in SIMemoryLegalizer and
MachineMemOperand::getMergedOrdering.
Reviewed By: efriedma, rampitec
Differential Revision: https://reviews.llvm.org/D106729
Update AMDGPU gfx90a memory model to make coarse grain memory allocations
consistent when fine grained system scope atomic acquire and release is
performed.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D105137
Since this method can apply to cmpxchg operations, make sure it's clear
what value we're actually retrieving. This will help ensure we don't
accidentally ignore the failure ordering of cmpxchg in the future.
We could potentially introduce a getOrdering() method on AtomicSDNode
that asserts the operation isn't cmpxchg, but not sure that's
worthwhile.
Differential Revision: https://reviews.llvm.org/D103338
This restores previous behaviour and is a step toward removing
unbundling entirely.
Reviewed By: foad, rampitec
Differential Revision: https://reviews.llvm.org/D99061
Replace individual operands GLC, SLC, and DLC with a single cache_policy
bitmask operand. This will reduce the number of operands in MIR and I hope
the amount of code. These operands are mostly 0 anyway.
Additional advantage that parser will accept these flags in any order unlike
now.
Differential Revision: https://reviews.llvm.org/D96469
The AMD GPU SIMemoryLegalizer was using the ordering address space
rather than the instruction address space when determining the
s_waitcnt to generate to ensure that a read-modify-write atomic has
completed. This resulted in additional unnecessary counters being
waited on.
Differential Revision: https://reviews.llvm.org/D96743
We are using AtomicNoRet map in multiple places to determine
if an instruction atomic, rtn or nortn atomic. This method
does not work always since we have some instructions which
only has rtn or nortn version.
One such instruction is ds_wrxchg_rtn_b32 which does not have
nortn version. This has caused changes in memory legalizer
tests.
Differential Revision: https://reviews.llvm.org/D96639
Treat a non-atomic volatile load and store as a relaxed atomic at
system scope for the address spaces accessed. This will ensure all
relevant caches will be bypassed.
A volatile atomic is not changed and still only bypasses caches upto
the level specified by the SyncScope operand.
Differential Revision: https://reviews.llvm.org/D94214
It is possible for copies or spills to be inserted in the middle of indirect
addressing sequences which use VGPR indexing. Spills to accvgprs could be
effected by the indexing mode.
Add new pseudo instructions that are expanded after register allocation to avoid
the problematic spill or copy placement.
Differential Revision: https://reviews.llvm.org/D91048
- Make the SIMemoryLegalizer insertAcquire function be in the same
order for each target to be consistent.
Differential Revision: https://reviews.llvm.org/D89880
Summary:
D78800 skipped generating cache invalidating instrucions altogether
on AMDPAL. However, this is sometimes too restrictive - we want a
more flexible option to be able to toggle this behaviour on and off
while we work towards developing a correct implementation of the
alternative memory model.
Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, dexonsmith, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D84448
Summary:
Frontend guarantees that coherent accesses have
corresponding cache policy bits set (glc, dlc).
Therefore there is no need for extra instructions
that invalidate cache.
Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78800
