5b7d56f6f7
This PR adds support for `if-let` clauses, as proposed in bytecodealliance/rfcs#21. These clauses augment the left-hand side (pattern-matching phase) of rules in the ISLE instruction-selection DSL with sub-patterns matching on sub-expressions. The ability to list additional match operations to perform, out-of-line from the original toplevel pattern, greatly simplifies some idioms. See the RFC for more details and examples of use.
30 lines
469 B
Common Lisp
30 lines
469 B
Common Lisp
(type u32 (primitive u32))
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(decl pure A (u32 u32) u32)
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(extern constructor A A)
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(decl B (u32 u32) u32)
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(extern extractor B B)
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(decl C (u32 u32 u32 u32) u32)
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(decl pure predicate () u32)
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(rule (predicate) 1)
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(rule (C a b c (B d e))
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(if-let (B f g) d)
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(if-let h (A a b))
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(A h a))
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(rule (C a b c d)
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(if (predicate))
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42)
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(rule (C a b a b)
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(if-let x (D a b))
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x)
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(decl pure D (u32 u32) u32)
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(rule (D x 0) x)
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(rule (D 0 x) x)
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