[PATCH] D144563: [SimplifyCFG] Improve the precision of `PtrValueMayBeModified`

[DianQK via Phabricator via llvm-commits]

DianQK added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/SimplifyCFG.cpp:7132
+            PtrValueMayBeModified = true;
+          }
+          if (!(GEP->isInBounds() &&
----------------
DianQK wrote:
> nikic wrote:
> > The first block probably isn't supposed to be there?
> Sorry I didn't get.
> First, we only focus two cases:
> a. getelementptr (TY, null, not zero)          -> maybe be modified
> a. getelementptr inbounds (TY, null, not zero) -> poison?
> 
> The first
> ```
> if (!GEP->isInBounds()) {
>    PtrValueMayBeModified = true;
> }
> ```
> is the "a" case.
These two cases are:
a. getelementptr (TY, null, not zero) -> maybe be modified
b. getelementptr inbounds (TY, null, not zero) -> poison?


Repository:
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  https://reviews.llvm.org/D144563/new/

https://reviews.llvm.org/D144563