[PATCH] D129072: [RISCV] Fix the scale of getIntMatCost and also need adjust for getIntImmCost

[Zixuan Wu via Phabricator via llvm-commits]

zixuan-wu added a comment.

In D129072#3629019 <https://reviews.llvm.org/D129072#3629019>, @liaolucy wrote:

> I would like to ask a question, is this patch to reduce code size?

I think the instruction cost model can be used both in code size and performance. Normally it's in TCK_SizeAndLatency kind.



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Comment at: llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp:384
   bool IsRV64 = ActiveFeatures[RISCV::Feature64Bit];
   bool HasRVC = CompressionCost && ActiveFeatures[RISCV::FeatureStdExtC];
   int PlatRegSize = IsRV64 ? 64 : 32;
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craig.topper wrote:
> HasRVC also considers ‘CompressionCost’ so it only scaled the value when that was passed. TargetTransformInfo doesn’t set that flag.
I think it's better to use same multiplicative factor in one cost function, no matter the RVC is enable or not.


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https://reviews.llvm.org/D129072