[PATCH] D47895: llvm: Add support for "-fno-delete-null-pointer-checks"

[Manoj Gupta via Phabricator via llvm-commits]

manojgupta added a comment.

In https://reviews.llvm.org/D47895#1125388, @efriedma wrote:

> Missing LangRef changes.
>
> How did you come up with the set of checks which need to be updated?  Quickly grepping through the source, I found you missed at least lib/Analysis/ValueTracking.cpp, include/llvm/IR/CallSite.h, lib/Analysis/LazyValueInfo.cpp, and lib/Analysis/ConstantFolding.cpp .


Thanks Eli,

My interpretation (based on GCC description) is only the analysis/optimizations that assume pointer dereference => non-null and null dereference => undefined need to be fixed. If an analysis can prove non-nullablility based on any criteria except dereference,  it should be fine to remove null checks.

I am going to recheck the list of files you suggested and also recheck LLVM overall.
I believe that there are probably more places that I might have missed. Appreciate a lot if you and other reviewers can point me to more optimizations/analysis that should be updated.


Repository:
  rL LLVM

https://reviews.llvm.org/D47895