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3 Commits

Author SHA1 Message Date
Marcelina Kościelnicka 2f8541a92e opt_expr: Fix X and CO outputs for $alu identity-mapping rules. 2020-04-16 11:48:29 +02:00
Marcelina Kościelnicka 6c16fd760b opt_expr: Add more $alu optimizations. 
Detect the places in the $alu where the carry bit is constant (due to
const A[i] == B[i] ^ BI) and split it into smaller $alu at these points.

Also, make the existing const-carry detection for low bits more generic
(now handles cases where both BI and CI are constant, but not equal to
one another).

Fixes #1912.
 2020-04-14 21:48:13 +02:00
Eddie Hung 5e2562f1a2 opt_expr: add $alu tests 2020-03-19 14:57:10 -07:00