[PATCH] D42123: Derive GEP index type from Data Layout

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy added inline comments.


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Comment at: ../lib/Analysis/ScalarEvolution.cpp:3667
 bool ScalarEvolution::isSCEVable(Type *Ty) const {
   // Integers and pointers are always SCEVable.
   return Ty->isIntegerTy() || Ty->isPointerTy();
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Generally speaking; the SCEV changes need to be tested.


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Comment at: ../lib/Analysis/ScalarEvolution.cpp:3675
   assert(isSCEVable(Ty) && "Type is not SCEVable!");
+  if (Ty->isPointerTy())
+    return getDataLayout().getIndexTypeSizeInBits(Ty);
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I don't think this is a correct place to make this change -- the size of a pointer is the size of a pointer.  I think you need to change the SCEV corresponding to GEP(Ptr, Idx) to be "sext(Ptr) + Idx" or "Ptr + sext(Idx)" depending on their relative sizes.


Repository:
  rL LLVM

https://reviews.llvm.org/D42123