What's old is new again: I loved following Leopard Logic (https://www.crunchbase.com/organization/leopard-logic) back in the early 2000s. They had a rapidly reconfigurable FPGA coprocessor bolted to a MIPS or ARM processor. The FPGA had multiple dynamic "planes" (4?) of FPGA configuration so, once the system was booted and the FPGAs programmed, you could switch to FPGA plane 1 to do MP3 decode, then switch to FPGA plane 2 to do MPEG2 decode, then switch to plane 3 for XYZ, etc.

Some other related companies had modified GCC to automate the process of co-processor offload.