[PATCH] D39556: [ConstantFold] Support vector index when factoring out GEP index into preceding dimensions

[Haicheng Wu via Phabricator via llvm-commits]

haicheng added inline comments.


================
Comment at: lib/IR/ConstantFold.cpp:2214
+  bool Unknown =
+      !isa<ConstantInt>(Idxs[0]) && (!isa<ConstantDataVector>(Idxs[0]));
   for (unsigned i = 1, e = Idxs.size(); i != e;
----------------
mssimpso wrote:
> You should be able to just use `!isa<Constant>(Idxs[0])` for these kinds of checks I think. All GEP indices are required to be integers or integer vectors.
I think `Unknown` is set to true if we don't know the indices are inbound or not.  Since we only check the bound for `ConstantInt ` and  `ConstantDataVector`, I just white list these two.  It is true that the constant index can only be constant integer and constant integer vector, but wild constant expression (e.g. ptrtoint) is also allowed.  If I change the code to !`isa<Constant>`, many test cases fail.


Repository:
  rL LLVM

https://reviews.llvm.org/D39556