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AR# 57985

Vivado Synthesis - The tool is hanging during compilation of block of loops


The Vivado tool hangs during the compilation stage of synthesis and the job runs for days without completing. 

The following is an example of what the log shows:

starting synthesize : Time (s): cpu = 00:00:05 ; elapsed = 00:00:08 . Memory (MB): peak = 186.184 ; gain = 51.695
INFO: [Synth 8-638] synthesizing module 'testcase' [/../.../testcase.v:1]
        Parameter DISP_DEPTH bound to: 96 - type: integer 
        Parameter PIXEL_DEPTH bound to: 64 - type: integer


This issue is related to how the Vivado Synthesis compiler is unrolling loops. 

This problem is fixed in the 2014.3 Vivado release.

The following work-arounds can help resolve issues related to loops for releases prior to 2014.3:

Option 1:
set_param synth.elaboration.rodinMoreOptions {rt::set_parameter simplifyCascadedMerge 0;rt::set_parameter mergeReconvergentCasePartitions false; rt::set_parameter mergeReconvergentLogicPartitions false}
Option 2:

Use the -directive RunTimeOptimized switch, the details of which can be found in UG901.
AR# 57985
Date 10/08/2014
Status Active
Type Known Issues
  • Vivado Design Suite