[PATCH] D99240: [ConstantFolding] Look through local aliases when simplify GEPs

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks created this revision.
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MSVC-style RTTI uses GEPs through local aliases for vtables.

With this patch, we can simplify the following C++ code into just one
function with a constant return value:

  namespace {
          struct A {
                  virtual int f() = 0;
                  virtual ~A() = default;
          };
          struct B: A {
                  virtual int f() override { return 41; }
                  virtual ~B() = default;
          };
  }
  
  int foo() {
          std::unique_ptr<A> a = std::make_unique<B>();
          return a->f();
  }


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D99240

Files:
  llvm/include/llvm/IR/Value.h
  llvm/lib/Analysis/ConstantFolding.cpp
  llvm/lib/IR/Value.cpp
  llvm/test/Transforms/InstSimplify/ConstProp/gep-alias.ll

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