On Wed, Sep 17, 2014 at 04:59:38PM -0700, Cherry Vanc wrote: > I added a functional unit to the MIPS 5kc backend for memory > operations and noticed that a function started getting mtlo / mflo > instructions in the prologue/epilogue. The function does not have any > mult/div instructions. > > When I debug the source of these instructions, I can only tap into the > code path when GCC is looking for the instruction suiting the RTL > pattern (final.c). > > Why are these instructions being generated when I simply just added a > functional unit to the pipeline description ? How can I debug why they > are being generated in the first place ? Add -dap to your gcc command line. Also use -S, not -c. Cheers, Segher
