[PATCH] D151659: Constant propogation through freeze instruction

[Mikhail Gudim via Phabricator via llvm-commits]

mgudim added a comment.

@nikic Thanks for taking a look!

My understanding is that if the argument of `freeze` instruction is `undef` then `V0State.isUnknownOrUndef()` will return `true` and we exit. In the value lattice `undef` and `constant` are separate states (`llvm-project/llvm/include/llvm/Analysis/ValueLattice.h : 45`)
Also, the test checks that freeze instructions with `undef` argument remain untouched `%fr = freeze i32 undef` - the test passed with my change.

I have also tested with poison: the instruction `%fr = freeze i32 poison` remains untouched.  Does this look right? Or am I still misunderstanding?


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  https://reviews.llvm.org/D151659/new/

https://reviews.llvm.org/D151659