b96a6ea0a9
D71264 started using a context instruction in a computeKnownBits() call. However, if aliasing between two GEPs is checked, then the choice of context instruction will be different for alias(GEP1, GEP2) and alias(GEP2, GEP1), which is not supposed to happen. Resolve this by remembering which GEP a certain VarIndex belongs to, and use that as the context instruction. This makes the choice of context instruction predictable and symmetric. It should be noted that this choice of context instruction is non-optimal (just like the previous choice): The AA query result is only valid at points that are reachable from *both* instructions. Using either one of them is conservatively correct, but a larger context may also be valid to use. Differential Revision: https://reviews.llvm.org/D93183
The LLVM Compiler Infrastructure ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you are writing a package for LLVM, see docs/Packaging.rst for our suggestions.