Extend the peepopt shiftmul matcher
#3873
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| Original file line number | Diff line number | Diff line change | ||||||
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| @@ -0,0 +1,160 @@ | ||||||||
| pattern shiftmul_left | ||||||||
| // | ||||||||
| // Optimize mul+shift pairs that result from expressions such as foo[s*W+:W] | ||||||||
| // | ||||||||
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| match shift | ||||||||
| select shift->type.in($shift, $shiftx, $shl) | ||||||||
| select shift->type.in($shl) || param(shift, \B_SIGNED).as_bool() | ||||||||
| filter !port(shift, \B).empty() | ||||||||
| endmatch | ||||||||
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| match neg | ||||||||
|
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Suggested change
Without this it tries to access port |
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| if shift->type.in($shift, $shiftx) | ||||||||
| select neg->type == $neg | ||||||||
| index <SigSpec> port(neg, \Y) === port(shift, \B) | ||||||||
| filter !port(shift, \A).empty() | ||||||||
| endmatch | ||||||||
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| // the left shift amount | ||||||||
| state <SigSpec> shift_amount | ||||||||
| // log2 scale factor in interpreting of shift_amount | ||||||||
| // due to zero padding on the shift cell's B port | ||||||||
| state <int> log2scale | ||||||||
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| code shift_amount log2scale | ||||||||
| if (neg) { | ||||||||
| // case of `$shift`, `$shiftx` | ||||||||
| shift_amount = port(neg, \A); | ||||||||
| if (!param(neg, \A_SIGNED).as_bool()) | ||||||||
| shift_amount.append(State::S0); | ||||||||
| } else { | ||||||||
| // case of `$shl` | ||||||||
| shift_amount = port(shift, \B); | ||||||||
| if (!param(shift, \B_SIGNED).as_bool()) | ||||||||
| shift_amount.append(State::S0); | ||||||||
| } | ||||||||
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| // at this point shift_amount is signed, make | ||||||||
| // sure we can never go negative | ||||||||
| if (shift_amount.bits().back() != State::S0) | ||||||||
| reject; | ||||||||
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| while (shift_amount.bits().back() == State::S0) { | ||||||||
| shift_amount.remove(GetSize(shift_amount) - 1); | ||||||||
| if (shift_amount.empty()) reject; | ||||||||
| } | ||||||||
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| log2scale = 0; | ||||||||
| while (shift_amount[0] == State::S0) { | ||||||||
| shift_amount.remove(0); | ||||||||
| if (shift_amount.empty()) reject; | ||||||||
| log2scale++; | ||||||||
| } | ||||||||
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| if (GetSize(shift_amount) > 20) | ||||||||
| reject; | ||||||||
| endcode | ||||||||
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| state <SigSpec> mul_din | ||||||||
| state <Const> mul_const | ||||||||
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| match mul | ||||||||
| select mul->type.in($mul) | ||||||||
| index <SigSpec> port(mul, \Y) === shift_amount | ||||||||
| filter !param(mul, \A_SIGNED).as_bool() | ||||||||
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| choice <IdString> constport {\A, \B} | ||||||||
| filter port(mul, constport).is_fully_const() | ||||||||
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| define <IdString> varport (constport == \A ? \B : \A) | ||||||||
| set mul_const SigSpec({port(mul, constport), SigSpec(State::S0, log2scale)}).as_const() | ||||||||
| // get mul_din unmapped (so no `port()` shorthand) | ||||||||
| // because we will be using it to set the \A port | ||||||||
| // on the shift cell, and we want to stay close | ||||||||
| // to the original design | ||||||||
| set mul_din mul->getPort(varport) | ||||||||
| endmatch | ||||||||
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| code | ||||||||
| { | ||||||||
| if (mul_const.empty() || GetSize(mul_const) > 20) | ||||||||
| reject; | ||||||||
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| // make sure there's no overlap in the signal | ||||||||
| // selections by the shiftmul pattern | ||||||||
| if (GetSize(port(shift, \A)) > mul_const.as_int()) | ||||||||
| reject; | ||||||||
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| int factor_bits = ceil_log2(mul_const.as_int()); | ||||||||
| // make sure the multiplication never wraps around | ||||||||
| if (GetSize(shift_amount) < factor_bits + GetSize(mul_din)) | ||||||||
| reject; | ||||||||
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| if (neg) { | ||||||||
| // make sure the negation never wraps around | ||||||||
| if (GetSize(port(shift, \B)) < factor_bits + GetSize(mul_din) | ||||||||
| + log2scale + 1) | ||||||||
| reject; | ||||||||
| } | ||||||||
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| did_something = true; | ||||||||
| log("left shiftmul pattern in %s: shift=%s, mul=%s\n", log_id(module), log_id(shift), log_id(mul)); | ||||||||
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| int const_factor = mul_const.as_int(); | ||||||||
| int new_const_factor = 1 << factor_bits; | ||||||||
| SigSpec padding(State::Sm, new_const_factor-const_factor); | ||||||||
| SigSpec old_y = port(shift, \Y), new_y; | ||||||||
| int trunc = 0; | ||||||||
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| if (GetSize(old_y) % const_factor != 0) { | ||||||||
| trunc = const_factor - GetSize(old_y) % const_factor; | ||||||||
| old_y.append(SigSpec(State::Sm, trunc)); | ||||||||
| } | ||||||||
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| for (int i = 0; i*const_factor < GetSize(old_y); i++) { | ||||||||
| SigSpec slice = old_y.extract(i*const_factor, const_factor); | ||||||||
| new_y.append(slice); | ||||||||
| new_y.append(padding); | ||||||||
| } | ||||||||
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| if (trunc > 0) | ||||||||
| new_y.remove(GetSize(new_y)-trunc, trunc); | ||||||||
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| { | ||||||||
| // Now replace occurences of Sm in new_y with bits | ||||||||
| // of a dummy wire | ||||||||
| int padbits = 0; | ||||||||
| for (auto bit : new_y) | ||||||||
| if (bit == SigBit(State::Sm)) | ||||||||
| padbits++; | ||||||||
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| SigSpec padwire = module->addWire(NEW_ID, padbits); | ||||||||
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| for (int i = new_y.size() - 1; i >= 0; i--) | ||||||||
| if (new_y[i] == SigBit(State::Sm)) { | ||||||||
| new_y[i] = padwire.bits().back(); | ||||||||
| padwire.remove(padwire.size() - 1); | ||||||||
| } | ||||||||
| } | ||||||||
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| SigSpec new_b = {mul_din, SigSpec(State::S0, factor_bits)}; | ||||||||
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| shift->setPort(\Y, new_y); | ||||||||
| shift->setParam(\Y_WIDTH, GetSize(new_y)); | ||||||||
| if (shift->type == $shl) { | ||||||||
| if (param(shift, \B_SIGNED).as_bool()) | ||||||||
| new_b.append(State::S0); | ||||||||
| shift->setPort(\B, new_b); | ||||||||
| shift->setParam(\B_WIDTH, GetSize(new_b)); | ||||||||
| } else { | ||||||||
| SigSpec b_neg = module->addWire(NEW_ID, GetSize(new_b) + 1); | ||||||||
| module->addNeg(NEW_ID, new_b, b_neg); | ||||||||
| shift->setPort(\B, b_neg); | ||||||||
| shift->setParam(\B_WIDTH, GetSize(b_neg)); | ||||||||
| } | ||||||||
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| blacklist(shift); | ||||||||
| accept; | ||||||||
| } | ||||||||
| endcode | ||||||||
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It looks like this cleans up the removal of the dffmux pattern in a0e99a9
Originally added in b8774ae
The changes (removals) concerning init look fine to me.
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Yes, can add that to the commit message