Re: bug in lra-constraints.c (simple_move_p register_move_cost)

[Vladimir Makarov]

On 2014-12-16 9:53 AM, BELBACHIR Selim wrote:
Hi,
I may have found a bug when I was trying to port my private backend to new LRA 
pass (using gcc 4.9.2+patches).

In lra-constraints.c, in function simple_move_p, the target hook 
targetm.register_move_cost is called with two badly swapped parameters :

         targetm.register_move_cost (GET_MODE (src), sclass, dclass)

should be :

         targetm.register_move_cost (GET_MODE (src), dclass, sclass)


In my port of GCC it leads to an error when checking constrain_operands at the 
end of LRA pass


Thanks for reporting this typo.  I'll fix it soon.  It did not affect 
other ports as usually the cost is symmetric relative to the args 
(especially when the cost is 2).