[llvm] [SeparateConstOffsetFromGEP] Support GEP reordering for different types (PR #90802)

[Nikita Popov via llvm-commits]

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@@ -1017,6 +1016,51 @@ bool SeparateConstOffsetFromGEP::reorderGEP(GetElementPtrInst *GEP,
       IsChainInBounds &= KnownPtrGEPIdx.isNonNegative();
     }
   }
+  TypeSize GEPSize = DL->getTypeSizeInBits(GEP->getSourceElementType());
+  TypeSize PtrGEPSize = DL->getTypeSizeInBits(PtrGEP->getSourceElementType());
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nikic wrote:

I'm not suggesting that you perform an in-place rewrite, but rather than you preserve the original element types of the GEPs. If you have `gep t2, (gep t1, p, i1), i2`, you should be able to rewrite it to `gep t1 (gep t2, p, i2), i1` without changing types or index values.

https://github.com/llvm/llvm-project/pull/90802