Fix UInt8/UInt16 comparison after wrapping arithmetic (#694)#713
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Fix UInt8/UInt16 comparison after wrapping arithmetic (#694)#713
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Comparisons (Eq, Neq, Lt, Lte, Gt, Gte) on UInt8/UInt16 after wrapping arithmetic (add_mod, sub_mod, mul_mod, shift_left, xor, or, etc.) produced wrong C code. The uint32 intermediate from mk_arith was compared directly without masking back to the original width. For example, (255uy +%^ 1uy) = 0uy generated: (uint32_t)255 + (uint32_t)1 == 0 => 256 == 0 => false (WRONG) Fix: handle comparisons in mk_expr (not mk_arith) with a dedicated pattern that only widens+masks operands containing arithmetic subexpressions. Atomic operands (variables, field accesses, etc.) are compared at their native width without unnecessary casts. Now generates: simple: a == b (no casts) arith: ((uint32_t)a + (uint32_t)b & 0xFFU) == c (only arith side) Fixes #694. Also fixes #689, #691, #692, #693 (same root cause). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Comparisons (Eq, Neq, Lt, Lte, Gt, Gte) on UInt8/UInt16 after wrapping arithmetic (add_mod, sub_mod, mul_mod, shift_left, xor, or, etc.) produced wrong C code. The uint32 intermediate from mk_arith was compared directly without masking back to the original width.
For example, (255uy +%^ 1uy) = 0uy generated:
(uint32_t)255 + (uint32_t)1 == 0 => 256 == 0 => false (WRONG)
Fix: handle comparisons in mk_expr (not mk_arith) with a dedicated pattern that only widens+masks operands containing arithmetic subexpressions. Atomic operands (variables, field accesses, etc.) are compared at their native width without unnecessary casts.
Now generates:
simple: a == b (no casts)
arith: ((uint32_t)a + (uint32_t)b & 0xFFU) == c (only arith side)
Fixes #694. Also fixes #689, #691, #692, #693 (same root cause).