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Respect opt_expr -keepdc as per @cliffordwolf

This commit is contained in:
Eddie Hung 2019-08-22 08:37:27 -07:00
parent 379f33af54
commit 6f971470f8
2 changed files with 15 additions and 1 deletions
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2
passes/opt/opt_expr.cc
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@ -748,7 +748,7 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
if (cell->type.in(ID($shiftx), ID($shift))) { if (cell->type.in(ID($shiftx), ID($shift))) {
SigSpec sig_a = assign_map(cell->getPort(ID::A)); SigSpec sig_a = assign_map(cell->getPort(ID::A));
int width; int width;
bool trim_x = true; bool trim_x = cell->type == ID($shiftx) || !keepdc;
bool trim_0 = cell->type == ID($shift); bool trim_0 = cell->type == ID($shift);
for (width = GetSize(sig_a); width > 1; width--) { for (width = GetSize(sig_a); width > 1; width--) {
if ((trim_x && sig_a[width-1] == State::Sx) || if ((trim_x && sig_a[width-1] == State::Sx) ||

14
tests/opt/opt_expr.ys
View File

@ -277,3 +277,17 @@ check
equiv_opt opt_expr equiv_opt opt_expr
design -load postopt design -load postopt
select -assert-count 1 t:$shift r:A_WIDTH=10 %i select -assert-count 1 t:$shift r:A_WIDTH=10 %i
###########
design -reset
read_verilog -icells <<EOT
module opt_expr_shift_3bit_keepdc(input [9:0] a, input [3:0] b, output [2:0] y);
\$shift #(.A_SIGNED(0), .B_SIGNED(0), .A_WIDTH(14), .B_WIDTH(4), .Y_WIDTH(3)) shift (.A({4'b0x0x,a}), .B(b), .Y(y));
endmodule
EOT
check
equiv_opt opt_expr -keepdc
design -load postopt
select -assert-count 1 t:$shift r:A_WIDTH=13 %i