The existing way of managing clustered nodes was done through adding
weak edges between the neighbouring cluster nodes, which is a sort of
ordered queue. And this will be later recorded as `NextClusterPred` or
`NextClusterSucc` in `ScheduleDAGMI`.
But actually the instruction may be picked not in the exact order of the
queue. For example, we have a queue of cluster nodes A B C. But during
scheduling, node B might be picked first, then it will be very likely
that we only cluster B and C for Top-Down scheduling (leaving A alone).
Another issue is:
```
if (!ReorderWhileClustering && SUa->NodeNum > SUb->NodeNum)
std::swap(SUa, SUb);
if (!DAG->addEdge(SUb, SDep(SUa, SDep::Cluster)))
```
may break the cluster queue.
For example, we want to cluster nodes (order as in `MemOpRecords`): 1 3
2. 1(SUa) will be pred of 3(SUb) normally. But when it comes to (3, 2),
As 3(SUa) > 2(SUb), we would reorder the two nodes, which makes 2 be
pred of 3. This makes both 1 and 2 become preds of 3, but there is no
edge between 1 and 2. Thus we get a broken cluster chain.
To fix both issues, we introduce an unordered set in the change. This
could help improve clustering in some hard case.
One key reason the change causes so many test check changes is: As the
cluster candidates are not ordered now, the candidates might be picked
in different order from before.
The most affected targets are: AMDGPU, AArch64, RISCV.
For RISCV, it seems to me most are just minor instruction reorder, don't
see obvious regression.
For AArch64, there were some combining of ldr into ldp being affected.
With two cases being regressed and two being improved. This has more
deeper reason that machine scheduler cannot cluster them well both
before and after the change, and the load combine algorithm later is
also not smart enough.
For AMDGPU, some cases have more v_dual instructions used while some are
regressed. It seems less critical. Seems like test `v_vselect_v32bf16`
gets more buffer_load being claused.
Many tests use store to undef as a placeholder use, so just replace all of these with poison.
This reverts d246cc618adc52fdbd69d44a2a375c8af97b6106. We now handle composing subregister extracts through reg_sequence.
Fix introducing stack usage if a bitcast source operand is an illegal integer type cast to a legal vector type. This should cover more situations, but this is the first one I noticed.
This reverts commit ca33649abe5fad93c57afef54e43ed9b3249cd86.
This reverts commit e215a1e27d84adad2635a52393621eb4fa439dc9 as it broke both hip and openmp buildbots.
This reverts commit adaff46d087799072438dd744b038e6fd50a2d78. Drop the -O3 checks from default-attributes.hip. I don't know why they are different on some bots but reverting this is far too disruptive.
This reverts commits 677cc15e0ff2e0e6aa30538eb187990a6a8f53c0 and 78bc1b64a6dc3fb6191355a5e1b502be8b3668e7. The test CodeGenHIP/default-attributes.hip is failing on multiple bots even after the attempted fix including the following: - https://lab.llvm.org/buildbot/#/builders/3/builds/1473 - https://lab.llvm.org/buildbot/#/builders/65/builds/1380 - https://lab.llvm.org/buildbot/#/builders/161/builds/595 - https://lab.llvm.org/buildbot/#/builders/154/builds/1372 - https://lab.llvm.org/buildbot/#/builders/133/builds/1547 - https://lab.llvm.org/buildbot/#/builders/81/builds/755 - https://lab.llvm.org/buildbot/#/builders/40/builds/570 - https://lab.llvm.org/buildbot/#/builders/13/builds/748 - https://lab.llvm.org/buildbot/#/builders/12/builds/1845 - https://lab.llvm.org/buildbot/#/builders/11/builds/1695 - https://lab.llvm.org/buildbot/#/builders/190/builds/1829 - https://lab.llvm.org/buildbot/#/builders/193/builds/962 - https://lab.llvm.org/buildbot/#/builders/23/builds/991 - https://lab.llvm.org/buildbot/#/builders/144/builds/2256 - https://lab.llvm.org/buildbot/#/builders/46/builds/1614 These bots have been broken for a day, so reverting to get everything back to green.
Removing it from the codegen pipeline induces a lot of test churn because llc is no longer optimizing out implicit arguments to kernels. Mostly mechanical, but there are some creative test updates. I preferred to take the changes as-is in tests where the ABI isn't relevant. In cases where it's more relevant, or the optimize out logic was too ingrained in the test, I pre-run the optimization. Some cases manually add attributes to disable inputs.