The Altera® HLS compiler is not supported in Quartus® Prime Standard Edition v20.1.
As with the HLS compiler, DSP Builder, Intel FPGA SDK for OpenCL™, Intel FPGA RTE for OpenCL These tools are not supported by Quartus.
Support for these tools will be finalized in Quartus® Prime Standard Edition v19.1.
（Intel Quartus Prime Standard Edition: Version 20.1 Software and Device Support Release Notes
(Changes to Software Behavior section)
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Category: HLS
Tools: Altera® HLS Compiler
Devices: -