[Handshake] Remove handshake.select #5045
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I introduced handshake.select back in the day to distinct it from handshake.mux. What i somehow failed to realize is that `handshake.select` has always lowered to a unit-rate actor, which completely removes the need for the operation. The fix all along seems to just lower it to a comb/firrtl mux with unit rate semantics. Furthermore, looks like there was a bug in the lowerings, wherein the operands of `arith.select` in standard to handshake was being swapped (hence the change in max.mlir, which was previously incorrect). Handshake to FIRRTL is... eghh... could have done a "nicer" implementation which factors out the join logic, but i can't be bothered - this pass is supposed to be deprecated, anyways.
mikeurbach
reviewed
Apr 14, 2023
lucas-rami
reviewed
Apr 14, 2023
lucas-rami
approved these changes
Apr 17, 2023
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I introduced
handshake.selectback in the day to distinguish it fromhandshake.mux. What i somehow failed to realize is thathandshake.selecthas always lowered to a unit-rate actor, which completely removes the need for the operation. The fix all along seems to just lower it to a comb/firrtl mux with unit rate semantics.Furthermore, looks like there was a bug in the lowerings, wherein the operands of
arith.selectin standard to handshake was being swapped (hence the change in max.mlir, which was actually incorrect before).Handshake to FIRRTL is... eghh... could have done a "nicer" implementation which factors out the join logic, but i can't be bothered - this pass is supposed to be deprecated, anyways, and i can't wait for the day when it is removed.