Commit Graph

14 Commits

Author SHA1 Message Date
Matt Arsenault 8c4a35237a AMDGPU: Add pass to lower kernel arguments to loads
This replaces most argument uses with loads, but for
now not all.

The code in SelectionDAG for calling convention lowering
is actively harmful for amdgpu_kernel. It attempts to
split the argument types into register legal types, which
results in low quality code for arbitary types. Since
all kernel arguments are passed in memory, we just want the
raw types.

I've tried a couple of methods of mitigating this in SelectionDAG,
but it's easier to just bypass this problem alltogether. It's
possible to hack around the problem in the initial lowering,
but the real problem is the DAG then expects to be able to use
CopyToReg/CopyFromReg for uses of the arguments outside the block.

Exposing the argument loads in the IR also has the advantage
that the LoadStoreVectorizer can merge them.

I'm not sure the best approach to dealing with the IR
argument list is. The patch as-is just leaves the IR arguments
in place, so all the existing code will still compute the same
kernarg size and pointlessly lowers the arguments.

Arguably the frontend should emit kernels with an empty argument
list in the first place. Alternatively a dummy array could be
inserted as a single argument just to reserve space.

This does have some disadvantages. Local pointer kernel arguments can
no longer have AssertZext placed  on them as the equivalent !range
metadata is not valid on pointer  typed loads. This is mostly bad
for SI which needs to know about the known bits in order to use the
DS instruction offset, so in this case this is not done.

More importantly, this skips noalias arguments since this pass
does not yet convert this to the equivalent !alias.scope and !noalias
metadata. Producing this metadata correctly seems to be tricky,
although this logically is the same as inlining into a function which
doesn't exist. Additionally, exposing these loads to the vectorizer
may result in degraded aliasing information if a pointer load is
merged with another argument load.

I'm also not entirely sure this is preserving the current clover
ABI, although I would greatly prefer if it would stop widening
arguments and match the HSA ABI. As-is I think it is extending
< 4-byte arguments to 4-bytes but doesn't align them to 4-bytes.

llvm-svn: 335650
2018-06-26 19:10:00 +00:00
Matt Arsenault 8728c5f2db AMDGPU: Cleanup subtarget features
Try to avoid mutually exclusive features. Don't use
a real default GPU, and use a fake "generic". The goal
is to make it easier to see which set of features are
incompatible between feature strings.

Most of the test changes are due to random scheduling changes
from not having a default fullspeed model.

llvm-svn: 310258
2017-08-07 14:58:04 +00:00
Matt Arsenault 6c29c5acfe AMDGPU: Allow SIShrinkInstructions to work in non-SSA
Immediates can be folded as long as the immediate is a vreg.

Also undo commuting instructions if it didn't fold an immediate.

llvm-svn: 307575
2017-07-10 19:53:57 +00:00
Alexander Timofeev 982aee6a38 [AMDGPU] Switch scalarize global loads ON by default
Differential revision: https://reviews.llvm.org/D34407

llvm-svn: 307097
2017-07-04 17:32:00 +00:00
NAKAMURA Takumi e4a741376b Revert r307026, "[AMDGPU] Switch scalarize global loads ON by default"
It broke a testcase.

  Failing Tests (1):
      LLVM :: CodeGen/AMDGPU/alignbit-pat.ll

llvm-svn: 307054
2017-07-04 02:14:18 +00:00
Alexander Timofeev ea7f08bee5 [AMDGPU] Switch scalarize global loads ON by default
Differential revision: https://reviews.llvm.org/D34407

llvm-svn: 307026
2017-07-03 14:54:11 +00:00
Sam Kolton 9fa169601f [AMDGPU] Resubmit SDWA peephole: enable by default
Reviewers: vpykhtin, rampitec, arsenm

Subscribers: qcolombet, kzhuravl, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye

Differential Revision: https://reviews.llvm.org/D31671

llvm-svn: 299654
2017-04-06 15:03:28 +00:00
Ivan Krasin d4f70c70b9 Revert r299536. [AMDGPU] SDWA peephole: enable by default.
Reason: breaks multiple bots:

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/3988
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/1173

Original Review URL: https://reviews.llvm.org/D31671

llvm-svn: 299583
2017-04-05 19:58:12 +00:00
Sam Kolton 34e29784fb [AMDGPU] SDWA peephole: enable by default
Reviewers: vpykhtin, rampitec, arsenm

Subscribers: qcolombet, kzhuravl, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye

Differential Revision: https://reviews.llvm.org/D31671

llvm-svn: 299536
2017-04-05 12:00:45 +00:00
Matt Arsenault 8edfaee7be AMDGPU: Remove unnecessary ands when f16 is legal
Add a new node to act as a fancy bitcast from f16 operations to
i32 that implicitly zero the high 16-bits of the result.

Alternatively could try making v2f16 legal and canonicalizing
on build_vectors.

llvm-svn: 299246
2017-03-31 19:53:03 +00:00
Matt Arsenault 3dbeefa978 AMDGPU: Mark all unspecified CC functions in tests as amdgpu_kernel
Currently the default C calling convention functions are treated
the same as compute kernels. Make this explicit so the default
calling convention can be changed to a non-kernel.

Converted with perl -pi -e 's/define void/define amdgpu_kernel void/'
on the relevant test directories (and undoing in one place that actually
wanted a non-kernel).

llvm-svn: 298444
2017-03-21 21:39:51 +00:00
Matt Arsenault 86e02ce2dc AMDGPU: Fix unnecessary ands when packing f16 vectors
computeKnownBits didn't handle fp_to_fp16 to report
the high bits as 0. ARM maps the generic node to an instruction
that does not modify the high bits of the register, so introduce
a target node where the high bits are known 0.

llvm-svn: 297873
2017-03-15 19:04:26 +00:00
Matt Arsenault 7aad8fd8f4 Enable FeatureFlatForGlobal on Volcanic Islands
This switches to the workaround that HSA defaults to
for the mesa path.

This should be applied to the 4.0 branch.

Patch by Vedran Miletić <vedran@miletic.net>

llvm-svn: 292982
2017-01-24 22:02:15 +00:00
Konstantin Zhuravlyov f86e4b7266 [AMDGPU] Add f16 support (VI+)
Differential Revision: https://reviews.llvm.org/D25975

llvm-svn: 286753
2016-11-13 07:01:11 +00:00