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Add peepopt_muldiv, fixes #930

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Signed-off-by: Clifford Wolf <clifford@clifford.at>
This commit is contained in:
Clifford Wolf 2019-04-30 11:25:15 +02:00
parent 4306bebe58
commit b515fd2d25
6 changed files with 86 additions and 1 deletions
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36
passes/opt/wreduce.cc
View file

@ -529,6 +529,42 @@ struct WreducePass : public Pass {
module->connect(sig, Const(0, GetSize(sig)));
}
}
if (c->type.in("$div", "$mod", "$pow"))
{
SigSpec A = c->getPort("\\A");
int original_a_width = GetSize(A);
if (c->getParam("\\A_SIGNED").as_bool()) {
while (GetSize(A) > 1 && A[GetSize(A)-1] == State::S0 && A[GetSize(A)-2] == State::S0)
A.remove(GetSize(A)-1, 1);
} else {
while (GetSize(A) > 0 && A[GetSize(A)-1] == State::S0)
A.remove(GetSize(A)-1, 1);
}
if (original_a_width != GetSize(A)) {
log("Removed top %d bits (of %d) from port A of cell %s.%s (%s).\n",
original_a_width-GetSize(A), original_a_width, log_id(module), log_id(c), log_id(c->type));
c->setPort("\\A", A);
c->setParam("\\A_WIDTH", GetSize(A));
}
SigSpec B = c->getPort("\\B");
int original_b_width = GetSize(B);
if (c->getParam("\\B_SIGNED").as_bool()) {
while (GetSize(B) > 1 && B[GetSize(B)-1] == State::S0 && B[GetSize(B)-2] == State::S0)
B.remove(GetSize(B)-1, 1);
} else {
while (GetSize(B) > 0 && B[GetSize(B)-1] == State::S0)
B.remove(GetSize(B)-1, 1);
}
if (original_b_width != GetSize(B)) {
log("Removed top %d bits (of %d) from port B of cell %s.%s (%s).\n",
original_b_width-GetSize(B), original_b_width, log_id(module), log_id(c), log_id(c->type));
c->setPort("\\B", B);
c->setParam("\\B_WIDTH", GetSize(B));
}
}
if (!opt_memx && c->type.in("$memrd", "$memwr", "$meminit")) {
IdString memid = c->getParam("\\MEMID").decode_string();
RTLIL::Memory *mem = module->memories.at(memid);

3
passes/pmgen/Makefile.inc
View file

@ -16,7 +16,8 @@ passes/pmgen/peepopt.o: passes/pmgen/peepopt_pm.h
EXTRA_OBJS += passes/pmgen/peepopt_pm.h
.SECONDARY: passes/pmgen/peepopt_pm.h
PEEPOPT_PATTERN = passes/pmgen/peepopt_shiftmul.pmg
PEEPOPT_PATTERN = passes/pmgen/peepopt_shiftmul.pmg
PEEPOPT_PATTERN += passes/pmgen/peepopt_muldiv.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

@ -59,6 +59,7 @@ struct PeepoptPass : public Pass {
did_something = false;
peepopt_pm pm(module, module->selected_cells());
pm.run_shiftmul();
pm.run_muldiv();
}
}
}

36
passes/pmgen/peepopt_muldiv.pmg Normal file
View file

@ -0,0 +1,36 @@
pattern muldiv
state <SigSpec> t x y
match mul
select mul->type == $mul
select GetSize(port(mul, \A)) + GetSize(port(mul, \B)) <= GetSize(port(mul, \Y))
endmatch
code t x y
t = port(mul, \Y);
x = port(mul, \A);
y = port(mul, \B);
branch;
std::swap(x, y);
endcode
match div
select div->type.in($div)
index <SigSpec> port(div, \A) === t
index <SigSpec> port(div, \B) === x
endmatch
code
SigSpec div_y = port(div, \Y);
SigSpec val_y = y;
if (GetSize(div_y) != GetSize(val_y))
val_y.extend_u0(GetSize(div_y), param(div, \A_SIGNED).as_bool());
did_something = true;
log("muldiv pattern in %s: mul=%s, div=%s\n", log_id(module), log_id(mul), log_id(div));
module->connect(div_y, val_y);
autoremove(div);
reject;
endcode

2
passes/pmgen/pmgen.py
View file

@ -335,6 +335,8 @@ with open(outfile, "w") as f:
print(" blacklist_dirty = false;", file=f)
for index in range(len(blocks)):
block = blocks[index]
if block["pattern"] != current_pattern:
continue
if block["type"] == "match":
print(" if (st_{}.{} != nullptr && blacklist_cells.count(st_{}.{})) {{".format(current_pattern, block["cell"], current_pattern, block["cell"]), file=f)
print(" rollback = {};".format(index+1), file=f)

9
tests/simple/peepopt.v Normal file
View file

@ -0,0 +1,9 @@
module peepopt_shiftmul_0 #(parameter N=3, parameter W=3) (input [N*W-1:0] i, input [$clog2(N)-1:0] s, output [W-1:0] o);
assign o = i[s*W+:W];
endmodule
module peepopt_muldiv_0(input [1:0] i, output [1:0] o);
wire [3:0] t;
assign t = i * 3;
assign o = t / 3;
endmodule