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clockgate: EN can be a bit on a multi-bit wire

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This commit is contained in:
Emil J. Tywoniak 2024-09-11 19:18:25 +02:00
parent 8b464341c2
commit 1e999a3cb7
2 changed files with 38 additions and 13 deletions
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29
passes/techmap/clockgate.cc
View file

@ -73,20 +73,20 @@ struct ClockgatePass : public Pass {
// if the number of FFs associated with it is sufficent
struct ClkNetInfo {
// Original, ungated clock into enabled FF
Wire* clk_net;
SigBit clk_bit;
// Original clock enable into enabled FF
Wire* ce_net;
SigBit ce_bit;
bool pol_clk;
bool pol_ce;
unsigned int hash() const {
auto t = std::make_tuple(clk_net, ce_net, pol_clk, pol_ce);
auto t = std::make_tuple(clk_bit, ce_bit, pol_clk, pol_ce);
unsigned int h = mkhash_init;
h = mkhash(h, hash_ops<decltype(t)>::hash(t));
return h;
}
bool operator==(const ClkNetInfo& other) const {
return (clk_net == other.clk_net) &&
(ce_net == other.ce_net) &&
return (clk_bit == other.clk_bit) &&
(ce_bit == other.ce_bit) &&
(pol_clk == other.pol_clk) &&
(pol_ce == other.pol_ce);
}
@ -100,8 +100,8 @@ struct ClockgatePass : public Pass {
};
ClkNetInfo clk_info_from_ff(FfData& ff) {
Wire* clk = ff.sig_clk.as_wire();
Wire* ce = ff.sig_ce.as_wire();
SigBit clk = ff.sig_clk[0];
SigBit ce = ff.sig_ce[0];
ClkNetInfo info{clk, ce, ff.pol_clk, ff.pol_ce};
return info;
}
@ -147,7 +147,12 @@ struct ClockgatePass : public Pass {
FfData ff(nullptr, cell);
// It would be odd to get constants, but we better handle it
if (ff.has_ce && ff.sig_clk.is_wire() && ff.sig_ce.is_wire()) {
if (ff.has_ce) {
if (!ff.sig_clk.is_bit() || !ff.sig_ce.is_bit())
continue;
if (!ff.sig_clk[0].is_wire() || !ff.sig_ce[0].is_wire())
continue;
ce_ffs.insert(cell);
ClkNetInfo info = clk_info_from_ff(ff);
@ -159,7 +164,6 @@ struct ClockgatePass : public Pass {
}
for (auto& clk_net : clk_nets) {
log_debug("checking clk net %s\n", clk_net.first.clk_net->name.c_str());
auto& clk = clk_net.first;
auto& gclk = clk_net.second;
@ -176,10 +180,9 @@ struct ClockgatePass : public Pass {
if (!matching_icg_desc)
continue;
log_debug("building ICG for clk net %s\n", clk_net.first.clk_net->name.c_str());
Cell* icg = module->addCell(NEW_ID, matching_icg_desc->name);
icg->setPort(matching_icg_desc->ce_pin, clk.ce_net);
icg->setPort(matching_icg_desc->clk_in_pin, clk.clk_net);
icg->setPort(matching_icg_desc->ce_pin, clk.ce_bit);
icg->setPort(matching_icg_desc->clk_in_pin, clk.clk_bit);
gclk.new_net = module->addWire(NEW_ID);
icg->setPort(matching_icg_desc->clk_out_pin, gclk.new_net);
// Tie low DFT ports like scan chain enable
@ -187,7 +190,7 @@ struct ClockgatePass : public Pass {
icg->setPort(port, Const(0));
// Fix CE polarity if needed
if (!clk.pol_ce) {
SigBit ce_fixed_pol = module->NotGate(NEW_ID, clk.ce_net);
SigBit ce_fixed_pol = module->NotGate(NEW_ID, clk.ce_bit);
icg->setPort(matching_icg_desc->ce_pin, ce_fixed_pol);
}
}

22
tests/techmap/clockgate.ys
View file

@ -171,4 +171,26 @@ select -module bad2 -assert-count 0 t:\\pdk_icg
#------------------------------------------------------------------------------
# Regression test: EN is a bit from a multi-bit wire
design -reset
read_verilog << EOT
module dffe_wide_11( input clk, input [1:0] en,
input [3:0] d1, output reg [3:0] q1,
);
always @( posedge clk ) begin
if ( en[0] )
q1 <= d1;
end
endmodule
EOT
proc
opt
clockgate -pos pdk_icg ce:clkin:clkout -tie_lo scanen
select -assert-count 1 t:\\pdk_icg
#------------------------------------------------------------------------------
# TODO test -tie_lo