On Wed, 2012-09-19 at 18:42 +0100, Richard Sandiford wrote: > But the documentation says: > > This hook is never called with an invalid address. > > Since VOIDmode MEMs aren't valid, I think that should mean it's invalid > to call this hook (and rtlanal.c:address_cost) with VOIDmode. I never > got time to look at that though. (The culprit in the case I saw was > tree-ssa-loop-ivopts.c. Sandra had some improvements in this area, > so maybe they would fix this too.) > > Loading or storing BLKmode doesn't map to any instruction, so I don't > think returning true for zero is any better than what we do now. > > Richard
It looks like address_cost does get called with invalid addresses though and I think that happens on other platforms then MIPS, it is just that MIPS is the only one where the invalid address causes a compile time failure. For example, if you compile my test program without -mips16 the compiler does not abort but address_cost is still called with a VOIDmode MEM. What do you think about my patch minus the initial check for offset == 0? That would avoid the compile time abort. If we didn't want to do that it seems like address_cost should include a check for valid addresses before it calls the hook. I am sure that would cause failures on many platforms and get some attention. Steve Ellcey sell...@mips.com
