[PATCH] Handle accesses to sturctures with embedded arrays and different offsets better

[Daniel Berlin]

================
Comment at: lib/Analysis/BasicAliasAnalysis.cpp:1072
@@ +1071,3 @@
+        if (isActualObject(UnderlyingV1) && isActualObject(UnderlyingV2) &&
+            GEP1VariableIndices == GEP2VariableIndices)
+          if ((GEP2BaseOffset - (GEP1BaseOffset + V1Size) > 0) ||
----------------
Technically, the check should be "if the variable indices are equal, or we can prove they can't have values that make offset, size overlap when they wouldn't otherwise".

In particular, if we could prove the the variable indices are always 0 or positive, they can't overlap.

Sadly, we don't have range info in BasicAA to use, and this check is already strictly better than what we have now.

http://reviews.llvm.org/D8487

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