I'm not entirely sure this is the correct thing
to do with the global isel philosophy, but I think
this is necessary to handle how differently SGPRs
are used normally vs. from a condition.
For example, it makes sense to allow a copy
from a VGPR to an SGPR, but it makes no sense
to allow a copy from VGPRs to SGPRs used as
select mask.
This avoids regbankselecting strange code with
a truncate feeding directly into a condition field.
Now a copy is forced from sgpr(s1) to vcc, which is
more sensible to handle.
Some of these issues could probably avoided with making enough
operations resulting in i1 illegal. I think we can't avoid
this register bank for legality.
For example, an i1 and where one source is from a truncate, and
one source is a compare needs some kind of copy inserted to
make sure both are in condition registers.
llvm-svn: 350611
If a copy was needed to handle the condition of brcond, it was being
inserted before the defining instruction. Add tests for iterator edge
cases.
I find the existing code here suspect for the case where it's looking
for terminators that modify the register. It's going to insert a copy
in the middle of the terminators, which isn't allowed (it might be
necessary to have a COPY_terminator if anybody actually needs this).
Also legalize brcond for AMDGPU.
llvm-svn: 350595
It seems better to avoid using the callback if possible since
there are coverage assertions which are disabled if this is used.
Also fix missing tests. Only test the legal cases since it seems
legalization for build_vector is quite lacking.
llvm-svn: 349878
This patch restricts the capability of G_MERGE_VALUES, and uses the new
G_BUILD_VECTOR and G_CONCAT_VECTORS opcodes instead in the appropriate places.
This patch also includes AArch64 support for selecting G_BUILD_VECTOR of <4 x s32>
and <2 x s64> vectors.
Differential Revisions: https://reviews.llvm.org/D53629
llvm-svn: 348788
Avoid using allocateKernArg / AssignFn. We do not want any
of the type splitting properties of normal calling convention
lowering.
For now at least this exists alongside the IR argument lowering
pass. This is necessary to handle struct padding correctly while
some arguments are still skipped by the IR argument lowering
pass.
llvm-svn: 336373
Summary:
We could split sizes that are not power of two into smaller sized
G_IMPLICIT_DEF instructions, but this ends up generating
G_MERGE_VALUES instructions which we then have to handle in the instruction
selector. Since G_IMPLICIT_DEF is really a no-op it's easier just to
keep everything that can fit into a register legal.
Reviewers: arsenm
Reviewed By: arsenm
Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, rovka, kristof.beyls, dstuttard, tpr, t-tye, llvm-commits
Differential Revision: https://reviews.llvm.org/D48777
llvm-svn: 336041
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
Note a normal select test is not currently possible because this
relies on input registers tracked in SIMachineFunctionInfo which
are not currently serializable in MIR, but this does work end-to-end
from the IR.
llvm-svn: 335490
Matt Arsenault