arachne-pnr couldn't process wide bit width counter for lm4k

[BravoFpga]

When I compile following rtl,

`timescale 1ns/1ps
module cnt (CLK,A1);
input  CLK;
output reg A1; 
 
//parameter LENGTH = 'd153; // OKay
parameter LENGTH = 'd154; // Bad 
reg [LENGTH-1:0]    cnt;
 
always @(posedge CLK) cnt <= cnt + 1'b1;
always @(posedge CLK) A1 <= cnt[LENGTH-1];
 
endmodule

the arachne-pnr output assert message and abort program as follows.

rachne-pnr -d lm4k -P swg25tr -p cnt.pcf cnt.blif -o cnt.txt
seed: 1
device: lm4k
read_chipdb +/share/arachne-pnr/chipdb-lm4k.bin...
  supported packages: cm36, cm49, swg25tr
read_blif cnt.blif...
prune...
read_pcf cnt.pcf...
instantiate_io...
pack...
 
After packing:
IOs          2 / 18
GBs          0 / 8 
  GB_IOs     0 / 8 
LCs          157 / 3520
  DFF        4   
  CARRY      2   
  CARRY, DFF 151 
  DFF PASS   1   
  CARRY PASS 1
BRAMs        0 / 20
WARMBOOTs    0 / 1 
PLLs         0 / 0 
 
place_constraints...
promote_globals...
  promoted CLK$2, 155 / 155 
  promoted 1 nets
    1 clk 
  1 globals
    1 clk 
realize_constants...
place...
  initial wire length = 176
arachne-pnr: src/vector.hh:84: BasedVector<T, B>::reference BasedVector<T, B>::operator[](BasedVector<T, B>::size_type) [with T = int; typename std::vector<_RealType>::size_type B = 1; BasedVector<T, B>::reference = int&; BasedVector<T, B>::size_type = long unsigned int]: Assertion `i >= B && i < B + v.size()' failed.