It seems to be a hardware defect that the half inline constants do not
work as expected for the 16-bit integer operations (the inverse does
work correctly). Experimentation seems to show these are really
reading the 32-bit inline constants, which can be observed by writing
inline asm using op_sel to see what's in the high half of the
constant. Theoretically we could fold the high halves of the 32-bit
constants using op_sel.
The *_asm_all.s MC tests are broken, and I don't know where the script
to autogenerate these are. I started manually fixing it, but there's
just too many cases to fix. This also does break the
assembler/disassembler support for these values, and I'm not sure what
to do about it. These are still valid encodings, so it seems like you
should be able to use them in some way. If you wrote assembly using
them, you could have really meant it (perhaps to read the high bits
with op_sel?). The disassembler will print the invalid literal
constant which will fail to re-assemble. The behavior is also
different depending on the use context. Consider this example, which
was previously accepted and encoded using the inline constant:
v_mad_i16 v5, v1, -4.0, v3
; encoding: [0x05,0x00,0xec,0xd1,0x01,0xef,0x0d,0x04]
In contexts where an inline immediate is required (such as on gfx8/9),
this will now be rejected. For gfx10, this will produce the literal
encoding and change the printed format:
v_mad_i16 v5, v1, 0xc400, v3
; encoding: [0x05,0x00,0x5e,0xd7,0x01,0xff,0x0d,0x04,0x00,0xc4,0x00,0x00]
This is just another variation of the issue that we don't perfectly
handle round trip assembly/disassembly due to not tracking how
immediates were encoded. This doesn't matter much in practice, since
compilers don't emit the suboptimal encoding. I doubt any users are
relying on this behavior (although I did make use of the old behavior
to figure out what was wrong).
Fixes bug 46302.
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
This usually results in better code. Fixes using
inline asm with short2, and also fixes having a different
ABI for function parameters between VI and gfx9.
Partially cleans up the mess used for lowering of the d16
operations. Making v4f16 legal will help clean this up more,
but this requires additional work.
llvm-svn: 332953
Remove dependency of SDWA pass on SIShrinkInstructions.
The goal is to move SDWA even higher in the stack to avoid second run
of MachineLICM, MachineCSE and SIFoldOperands.
Also added handling to preserve original src modifiers.
Differential Revision: https://reviews.llvm.org/D33860
llvm-svn: 304665
An encoding does not allow to use SDWA in an instruction with
scalar operands, either literals or SGPRs. That is however possible
to copy these operands into a VGPR first.
Several copies of the value are produced if multiple SDWA conversions
were done. To cleanup MachineLICM (to hoist copies out of loops),
MachineCSE (to remove duplicate copies) and SIFoldOperands (to replace
SGPR to VGPR copy with immediate copy right to the VGPR) runs are added
after the SDWA pass.
Differential Revision: https://reviews.llvm.org/D33583
llvm-svn: 304219
Avoids instructions to pack a vector when the source is really
a scalar being broadcast.
Also be smarter and look for per-component fneg.
Doesn't yet handle scalar from upper half of register
or other swizzles.
llvm-svn: 303291
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
Matt Arsenault