FXML-2302: Support for negating PDLL constraints

[martin-luecke]

This PR introduces support for negation of constraints.

Previously, this could only be handled by creating an additional native call, e.g.

Constraint checkA(input: Attr);
Constarint checkNotA(input: Attr);

or by including an explicit additional operand for negation, e.g.
Constraint checkA(input: Attr, negated: Attr);

With this a constraint can simply be negated by prefixing it with !. e.g.

Constraint simpleConstraint(op: Op);

Pattern example with benefit(1) {
    let inputOp = op<test.bar>() ->(type: Type);
    let root = op<test.foo>(inputOp.0) -> ();
    !simpleConstraint(inputOp);
    simpleConstraint(root);
    erase root;
}

This pattern only matches if the constraint simpleConstraint is true for root and false for inputOp.

This required the following changes:
PDLL:

• make lexer aware of ! tokens
• support parsing ! as prefix for native constraints (only!)
• extend CallExpr with support for isNegated

PDL & PDLInterp Dialects

• adding an attribute isNegated with default value false to the operations pdl.apply_native_constraint and pdl_interp.apply_constraint
• make PDLToPDLInterpPass aware of this attribute

ByteCode:

• add isNegated to the generated bytecode
• When interpreting pdl_interp.apply_constraint branch depending on isNegated

This work is to be upstreamed to llvm-project

[ttjost]

Could you just add a test (failure maybe?) for the rewrite section?

[martin-luecke]

Thank you for the review!
I added the test 👍

[ttjost]

Great! Thanks for adding the test and making the necessary changes.

[ljfitz]

Thanks Martin - looks like a useful addition and clearly coded.