[LLVMdev] [PATCH] Add a Scalarize pass

[Nadav Rotem]

On Nov 14, 2013, at 2:32 PM, Richard Sandiford <rsandifo at linux.vnet.ibm.com> wrote:

> Richard Sandiford <rsandifo at linux.vnet.ibm.com> writes:
>> Are you worried that adding it to PMB will increase compile time?
>> The pass exits very early for any target that doesn't opt-in to doing
>> scalarisation at the IR level, without even looking at the function.
> 
> As an alternative, adding Scalarizer and InstCombine passes to
> SystemZPassConfig::addIRPasses() would probably give me most of the
> benefit without affecting the PMB.  Scalarizer itself would then not
> test TargetTransformInfo at all, at least in the initial version,
> and the scalarisation would still logically be done by codegen.
> Would that be OK?

I actually prefer that the Scalarizer would not touch TTI at all because I view scalarization a canonicalization phase for DSLs, much like SROA breaks structs.  I am okay with SystemZ adding it to its own compilation flow. 

Thanks,
Nadav