[PATCH] D121672: [AVR] Reject/Reserve R0~R15 on AVRTiny

Tue Mar 22 17:37:10 PDT 2022

aykevl added inline comments.

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Comment at: llvm/lib/Target/AVR/AVRRegisterInfo.cpp:60-62
   Reserved.set(AVR::R0);
   Reserved.set(AVR::R1);
   Reserved.set(AVR::R1R0);
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aykevl wrote:
> I think it would make sense to change these hardcoded `R0`/`R1`/`R1R0` registers to properties of `AVRSubtarget` (a bit like `getIORegisterOffset` for example). This would make the code below a bit more sensible: it could just reserve `R0`-`R15` instead of `R2`-`R17` which looks a bit strange.
> Such a change should probably need to be done in a separate patch, as a cleanup before this patch. Such a patch could also fix the hardcoded `R0`/`R1` registers in AVRFrameLowering.cpp, AVRExpandPseudoInsts.cpp, etc.
It looks like you already added these getters to `AVRSubtarget` in D119807.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D121672/new/

https://reviews.llvm.org/D121672