------- Comment #19 from steven at gcc dot gnu dot org 2010-02-05 14:58 -------
Interesting: for " -march=armv5te -mthumb" the code after IVOPTS is the perfect
code (from e.g. comment #17). The reason is that the address cost function for
Thumb (arm_thumb_address_cost) is of course not the same as that for ARM
(arm_arm_address_cost) so the correct code comes out automatically:
Address costs:
index costs 1
cst + index costs 1
In arm_arm_address_cost, "index" as a naked REG is the most expensive of all
addresses. In arm_thumb_address_cost it is the cheapest.
In conclusion: This is a target cost problem, not a generic rtl-optimization
bug. Adjusting as such. An ARM maintainer will have to figure out a better
implementation of arm_arm_address_cost.
--
steven at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|steven at gcc dot gnu dot |unassigned at gcc dot gnu
|org |dot org
Status|ASSIGNED |NEW
Component|rtl-optimization |target
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36712
