[PATCH] D62653: [Mips][DSP] Fix physregs incorrectly marked as dead.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

I would like to avoid having "undead" registers, which are marked dead but are semantically necessary, at any point.  That means never calling `setIsDead(false);` as part of instruction selection, even if the flags are eventually correct after post-isel hooks run.  The reason for this is that otherwise it's very confusing for anyone reading the code, or MIR dumps, to understand how it's supposed to work.

Why aren't these registers modeled precisely during isel?


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  https://reviews.llvm.org/D62653/new/

https://reviews.llvm.org/D62653