Cranelift: ISLE compiler should reject negative constant literals for u64

[bongjunj]

ISLE test case

(rule (simplify (bor ty (bxor ty (bxor ty (iconst_u ty -1) y) x) y)) (bor ty y (bxor ty x (iconst_u ty -1))))

Steps to Reproduce

• Add the file in any mid-end opt file. For example, cranelift/codegen/src/opts/arithmetic.isle
• Build the code generator with cargo build -p cranelift-codegen

Expected Results

1. The ISLE compiler MUST NOT produce invalid Rust code.
2. As -1 is in place of u64 (iconst_u <Type> <u64>), islec must either

• Reject the rule and raise ISLE compilation error, or
• Translate -1 as a u64 constant (e.g., 0xffffffffffffffff_u64)

Actual Results

islec produces 0xffffffffffffffffffffffffffffffff_u64, and this is an invalid Rust constant literal. As the literal requires 128-bit, and thus it cannot fit into 64-bit datatype.

Versions and Environment

Cranelift version or commit: 0.131.0

[bongjunj]

wasmtime/cranelift/codegen/src/isa/x64/lower.isle

Line 4557 in 511638f

(rule 1 (lower (has_type ty (vconst (u128_from_constant -1)))) (vector_all_ones))

-1 in place of u128 seems like an allowed behavior.

However, -1 in place of u64 is causing compilation failure (due to invalid Rust code generated).