[PATCH] D46315: [RegUsageInfoCollector] Fix handling of callee saved registers with CSR optimization.

[Jonas Paulsson via Phabricator via llvm-commits]

jonpa added a comment.

> The problem is that the big register is not necessarily covered by the sub regs. So you have to check for that.
>  E.g., on x86 saving xmm0 is not enough to say that ymm0 is preservered even if ymm0 doesn’t have any other sub reg.

Ah, I see. Would it work to instead use RegUnits, so that we first collect all saved/restored RegUnits, and then check which registers have all their RegUnits saved?


https://reviews.llvm.org/D46315