Instead of emitting the matcher code directly, return the rule matcher
and the skip reason as an Expected<RuleMatcher>.
This will let us record all matchers and process them before emission.
It's a somewhat unconventional use of Error, but it's nicer than, say,
std::pair, because of the bool conversions.
Differential Revision: https://reviews.llvm.org/D29743
llvm-svn: 294706
This lets us split out PatternToMatch from the top-level RuleMatcher,
where it doesn't really belong. That, in turn, lets us eventually
generate RuleMatchers from non-SelectionDAG sources.
llvm-svn: 294076
I think the initial version of r293172 was trying:
std::forward<Args...>(args)...
which doesn't compile. This seems like the correct way:
std::forward<Args>(args)...
llvm-svn: 293214
Summary:
This should make it possible to easily add everything needed to import all
the existing SelectionDAG rules. It should also serve the likely
kinds of GlobalISel rules (some of which are not currently representable
in SelectionDAG) once we've nailed down the tablegen definition for that.
The hierarchy is as follows:
MatcherRule - A matching rule. Currently used to emit C++ ISel code but will
| also be used to emit test cases and tablegen definitions in the
| near future.
|- Instruction(s) - Represents the instruction to be matched.
|- Instruction Predicate(s) - Test the opcode, arithmetic flags, etc. of an
| instruction.
\- Operand(s) - Represents a particular operand of the instruction. In the
| future, there may be subclasses to test the same predicates
| on multiple operands (including for variadic instructions).
\ Operand Predicate(s) - Test the type, register bank, etc. of an operand.
This is where the ComplexPattern equivalent
will be represented. It's also
nested-instruction matching will live as a
predicate that follows the DefUse chain to the
Def and tests a MatcherRule from that position.
Support for multiple instruction matchers in a rule has been retained from
the existing code but has been adjusted to assert when it is used.
Previously it would silently drop all but the first instruction matcher.
The tablegen-erated file is not functionally changed but has more
parentheses and no longer attempts to format the if-statements since
keeping track of the indentation is tricky in the presence of the matcher
hierarchy. It would be nice to have CMakes tablegen() run the output
through clang-format (when available) so we don't have to complicate
TableGen with pretty-printing.
It's also worth mentioning that this hierarchy will also be able to emit
TableGen definitions and test cases in the near future. This is the reason
for favouring explicit emit*() calls rather than the << operator.
Reviewers: aditya_nandakumar, rovka, t.p.northover, qcolombet, ab
Reviewed By: ab
Subscribers: igorb, dberris, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D28942
llvm-svn: 293172
This adds a basic tablegen backend that analyzes the SelectionDAG
patterns to find simple ones that are eligible for GlobalISel-emission.
That's similar to FastISel, with one notable difference: we're not fed
ISD opcodes, so we need to map the SDNode operators to generic opcodes.
That's done using GINodeEquiv in TargetGlobalISel.td.
Otherwise, this is mostly boilerplate, and lots of filtering of any kind
of "complicated" pattern. On AArch64, this is sufficient to match G_ADD
up to s64 (to ADDWrr/ADDXrr) and G_BR (to B).
Differential Revision: https://reviews.llvm.org/D26878
llvm-svn: 290284
Ahmed Bougacha