verilator

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Varun Koyyalagunta a3003a2d0f Add 15 new DFG peephole optimizations (#7553 )

- FOLD_SELF_SUB: x - x -> 0
- REMOVE_DIV_ONE / REMOVE_DIVS_ONE: x / 1 -> x (unsigned and signed)
- REMOVE_MUL_ZERO / REMOVE_MUL_ONE / REMOVE_MULS_ZERO / REMOVE_MULS_ONE:
  0 * x -> 0 and 1 * x -> x (unsigned and signed)
- REPLACE_NOT_LT/GTE/GT/LTE and their signed counterparts: eliminate a
  Not vertex by flipping the comparison operator

Test signals for the NOT-of-comparison GT/GTE variants use unique shift
amounts to prevent intra-pass CSE from merging their DfgGt/DfgGte vertices
with those produced when the complementary LT/LTE patterns fire, which
would otherwise trigger the !hasMultipleSinks() guard.

2026-05-08 12:39:33 -05:00