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Add peepopt_dffmuxext

This commit is contained in:
Eddie Hung 2019-09-04 12:35:15 -07:00
parent 0cee66e759
commit 2b86055848
3 changed files with 60 additions and 0 deletions
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1
passes/pmgen/Makefile.inc
View File

@ -27,6 +27,7 @@ $(eval $(call add_extra_objs,passes/pmgen/peepopt_pm.h))
PEEPOPT_PATTERN = passes/pmgen/peepopt_shiftmul.pmg
PEEPOPT_PATTERN += passes/pmgen/peepopt_muldiv.pmg
PEEPOPT_PATTERN += passes/pmgen/peepopt_dffmuxext.pmg
passes/pmgen/peepopt_pm.h: passes/pmgen/pmgen.py $(PEEPOPT_PATTERN)
$(P) mkdir -p passes/pmgen && python3 $< -o $@ -p peepopt $(filter-out $<,$^)

1
passes/pmgen/peepopt.cc
View File

@ -60,6 +60,7 @@ struct PeepoptPass : public Pass {
peepopt_pm pm(module, module->selected_cells());
pm.run_shiftmul();
pm.run_muldiv();
pm.run_dffmuxext();
}
}
}

58
passes/pmgen/peepopt_dffmuxext.pmg Normal file
View File

@ -0,0 +1,58 @@
pattern dffmuxext
state <IdString> muxAB
match dff
select dff->type == $dff
select GetSize(port(dff, \D)) > 1
endmatch
match mux
select mux->type == $mux
select GetSize(port(mux, \Y)) > 1
choice <IdString> AB {\A, \B}
//select port(mux, AB)[GetSize(port(mux, \Y))-1].wire
index <SigSpec> port(mux, \Y) === port(dff, \D)
define <IdString> BA (AB == \A ? \B : \A)
index <SigSpec> port(mux, BA) === port(dff, \Q)
filter port(mux, AB)[GetSize(port(mux, \Y))-1] == port(mux, AB)[GetSize(port(mux, \Y))-2]
set muxAB AB
endmatch
code
did_something = true;
log_cell(dff);
log_cell(mux);
SigSpec &D = mux->connections_.at(muxAB);
SigSpec &Q = dff->connections_.at(\Q);
int width = GetSize(D);
SigBit sign = D[width-1];
bool is_signed = sign.wire;
int i;
for (i = width-1; i >= 2; i--) {
if (!is_signed) {
module->connect(Q[i], sign);
if (D[i-1] != sign)
break;
}
else {
module->connect(Q[i], Q[i-1]);
if (D[i-2] != sign)
break;
}
}
mux->connections_.at(\A).remove(i, width-i);
mux->connections_.at(\B).remove(i, width-i);
mux->connections_.at(\Y).remove(i, width-i);
mux->fixup_parameters();
dff->connections_.at(\D).remove(i, width-i);
dff->connections_.at(\Q).remove(i, width-i);
dff->fixup_parameters();
log("dffmuxext pattern in %s: dff=%s, mux=%s; removed top %d bits.\n", log_id(module), log_id(dff), log_id(mux), width-i);
accept;
endcode