Hi: as to page http://gcc.gnu.org/ml/gcc/2010-05/msg00091.html, If the fpu register can not copied to/from memory directly, I have to use intermediate GPR registers.
In fact, I return GP_REGS if copying x to a register in class FP_REGS in any mode(including CCmode), this results in infinite recursive calling of memory_move_secondary_cost. After tracing cc1, I found the calling sequence is like: memory_move_secondary_cost (CCmode, ST_REGS, 1) --> memory_move_secondary_cost (CCmode, FP_REGS, 1) --> memory_move_secondary_cost (CCmode, ST_REGS, 1) --> memory_move_secondary_cost (CCmode, FP_REGS, 1) --> ....... infinite recursive.... It seems function default_secondary_reload always use ST_REGS as intermediate register for FP_REGS:CCmode according to reload_incc pattern. This is all what i found, and I have totally no idea about how reload pass works . any explanation? Thanks. -- Best Regards.
