making the IR dumps much nicer.
This is part 2/3 of the path to making dialect types more nice. Part 3/3 will
slightly generalize the set of characters allowed in pretty types and make it
more principled.
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PiperOrigin-RevId: 242249955
Historically, the LLVM IR dialect has been using the generic form of MLIR
operation syntax. It is verbose and often redundant. Introduce the custom
printing and parsing for all existing operations in the LLVM IR dialect.
Update the relevant documentation and tests.
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PiperOrigin-RevId: 241617393
These cleanups reflects some recent changes to the LLVM IR Dialect and the
infrastructure that affects it. In particular, add documentation on direct and
indirect function calls as well as remove the `call` and `call0` separation.
Change the prefix of custom types from `!llvm.type` to `!llvm` so that it
matches the IR. Remove the verifier check disallowing conditional branches to
the same block with arguments: identical arguments are now supported, and
different arguments will be caught later.
PiperOrigin-RevId: 237203452
Since the goal of the LLVM IR dialect is to reflect LLVM IR in MLIR, the
dialect and the conversion procedure must account for the differences betweeen
block arguments and LLVM IR PHI nodes. In particular, LLVM IR disallows PHI
nodes with different values coming from the same source. Therefore, the LLVM IR
dialect now disallows `cond_br` operations that have identical successors
accepting arguments, which would lead to invalid PHI nodes. The conversion
process resolves the potential PHI source ambiguity by injecting dummy blocks
if the same block is used more than once as a successor in an instruction.
These dummy blocks branch unconditionally to the original successors, pass them
the original operands (available in the dummy block because it is dominated by
the original block) and are used instead of them in the original terminator
operation.
PiperOrigin-RevId: 235682798
Addressing post-submit comments. The `getelementptr` operation now supports
non-constant indexes, similarly to LLVM, and this functionality is exercised by
the lowering to the dialect. Update the documentation accordingly.
List the values of integer comparison predicates, which currently correspond to
those of CmpIOp in MLIR. Ideally, we would use strings instead, but it
requires additional support for argument conversion in both the dialect
lowering pass and the LLVM translator.
PiperOrigin-RevId: 235678877
The LLVM IR pass was bootstrapped without user documentation, following LLVM's
language reference and existing conversions between MLIR standard operations
and LLVM IR instructions. Provide concise documentation of the LLVM IR dialect
operations. This documentation does not describe the semantics of the
operations, which should match that of LLVM IR, but highlights the structural
differences in operation definitions, in particular using attributes instead of
constant-only values. It also describes pseudo-operations that exist only to
make the LLVM IR dialect self-contained within MLIR.
While it could have been possible to generate operation description from
TableGen, this opts for a more concise format where groups of related
operations are described together.
PiperOrigin-RevId: 235149136
Brett Koonce