While not a user of the CCS line of compilers, I thought it worth mentioning that some of possible issues and complexity of writing a PIC32 compiler maybe due in part to the fact that unlike its predecessors, dsPIC33/30, PIC24, PIC18, PIC16, etc., the PIC32 is actually a PIC in name only.
Both the PIC32MX and PIC32MZ are based not on a Microchip designed core architecture, but a licensed MIPS M4K Core or Imagination MIPS microAptiv Core respectively. While Microchip has done fairly good job of hiding or masking many of the key core architecture differences from the average PIC C programmer, they are in fact present and significant.
BigDog