[PATCH] D54507: [ThinLTO] Handle chains of aliases

[Peter Collingbourne via Phabricator via llvm-commits]

pcc added inline comments.


================
Comment at: lib/Transforms/Utils/CanonicalizeAliases.cpp:51
+    // Convert to a direct alias of base object.
+    GA.replaceUsesOfWith(
+        GA2, ConstantExpr::getBitCast(GA2->getBaseObject(), GA2->getType()));
----------------
This isn't quite right; it will rewrite
```
ga1 = alias ga2
ga2 = alias gep(gv, 0, 1)
```
as
```
ga1 = alias gv
```
i.e. you will drop the offset from the alias. The implementation in https://reviews.llvm.org/D29781#1328720 handles this case correctly.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D54507/new/

https://reviews.llvm.org/D54507