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Re: IA-64 speculation patches have bad impact on ARM

Vladimir Makarov wrote:


I am agree with this. Two months ago Maxim submitted patches which affects only ia64 except one thing affecting all targets - the patch which builds more scheduling regions and as consequence permits more aggressive interblock scheduling.

Insn scheduling before the register allocation even without Maxim's patches is not safe when hard registers are used in RTL. It is a known bug (e.g. for x86_64) and it is in bugzilla. Jim Wilson wrote several possible solutions for this, no one is easy to implement except for switching off insn scheduling before RA (what is done for x86_64).

But we can restore the state (probably safe for most programs) what was before Maxim's patch. So Maxim could you do this (of course you can save max-sched-extend-regions-iters value for ia64 because it is probably safe for targets with many registers).


Considering that bug, I agree that by default there should be no additional regions. The patch will be posted in a few minutes.


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