Unsequenced assignment detection is very slow for large expressions

[spurserh]

A quick work-around hack is to set unsequenced_genbackwards = false in xlscc/translator.h

[spurserh]

pragma hls_top

void my_package(char x[32], char y[1]) { y[0] = 1 + x[0] - 2 x[1] - x[2] - x[4] + x[5] + x[6] - x[7] - x[10] - x[11] - 2 x[12] - x[13] - x[17] - x[19] - x[20] - x[22] + 2 x[23] - x[24] + x[25] - x[26] - x[27] - x[28] - x[29] - x[30] - 2 x[31]; }

[spurserh]

Probably obsoleted by https://github.com/google/xls/issues/572