[llvm] [GVN][PGO] Skip GVN if entry BlockFreq is 0 (PR #166336)

[Madhur Amilkanthwar via llvm-commits]

madhur13490 wrote:

> If this is to fix a compile time regression/issue, could there be some more investigation into what is actually causing it?
> 
> This seems like a very band-aid fix that might just paper over any actual issues.

The real culprit is the MD algorithms, which easily achieve quadratic complexity. I have been pushing for MSSA migration, but we have had little progress over the last few weeks. Once we migrate to MSSA, I expect the issue to go away.


https://github.com/llvm/llvm-project/pull/166336