[aarch64-port-dev ] AArch64: Why should we use rscratch1 instead of the temp register passed in?

[Pengfei Li (Arm Technology China)]

Hi Roman,

> .. the opr3 is marked as 'temp' (if it's assigned a valid value) which means it
> should be live for the lifetime of the instruction, but not before or after it.
> Maybe that comment is obsolete? Have you tried to use opr3/Rscratch ?


Thanks for your reply.

I've tried to use Rscratch and assertion failed at http://hg.openjdk.java.net/jdk/jdk/file/bbc7157ad9c5/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp#l1774.
RA assigns the same register (rscratch) to Rdividend just as your comment said. So that comment is not obsolete.

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Thanks,
Pengfei