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Re: porting to lra


On 08/24/2015 02:43 PM, shmeel gutl wrote:
are there any guidelines as to what needs to be done in the backend to
enable lra for 5.2?
Unfortunately, switching from reload to LRA can be a difficult task. Reload pass is driven by many machine target hooks. As LRA uses different algorithms these hooks might be misleading for it.
when I turn it on I get two types of errors. 1) insn
not recognized because fp hasn't been converted yet, and 2) max number
of generated reload insns.

any pointers will be appreciated
I did several LRA ports and they had different problems and changes were made in different code of machine-dependent files. I can say only that porting mostly needs to rework (sometimes to switch off) hooks used by reload. Sometimes very small changes in hooks are necessary, sometimes it needs a lot of changes (powerpc required the biggest efforts as the port uses a lot of tricks).

Could I ask you what target you are trying to port to LRA. I can look at it and evaluate how many efforts will be needed to do the port.



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