[llvm] [InstCombine] Extend folding of aggregate construction to cases when source aggregates are partially available (PR #100828)

[via llvm-commits]

weiguozhi wrote:

> > > It is the number of instructions executed by `opt -O3`.
> > 
> > 
> > So it's the number of instructions executed by opt, not the number of instructions executed by the generated code. Am I right?
> 
> Yes

Thanks for the confirmation. So it seems compile time impact is neutral. 

I can only see two files from https://github.com/dtcxzyw/llvm-opt-benchmark/commit/78a3cecad7713c6678e2f2d5e6c888f26b4d6b51. Both files reduced the dynamic number of insertvalue instructions, so it has positive performance impact.

https://github.com/llvm/llvm-project/pull/100828