[llvm] [Coroutines] Only rematerialize when operands are available after the suspend (PR #209195)

[Avi Kivity via llvm-commits]

avikivity wrote:

> > I tested on the file with the largest number of co_awaits, service/storage_service.cc (462).
> > Before:
> > real 1m4.369s user 1m1.906s sys 0m1.956s
> > After:
> > real 1m6.105s user 1m3.738s sys 0m1.878s
> > So, a measurable impact, but small (about 3%). Maybe 3% is high for a single compiler optimization.
> 
> Did you see change on performance?

Sorry, I missed this comment.

It will be hard for me to measure this, most of the performance sensitive code predates coroutines.

https://github.com/llvm/llvm-project/pull/209195