[PATCH] D121744: [SCCP] Update ValueLatticeElement blockaddresses when removing unreachable BasicBlocks

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers created this revision.
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Fixes a crash observed in ipsccp.

When SCCP's SCCPSolver determines that a BasicBlock is unreachable, it
removes it. Unfortunately, there may already be ValueLatticeElements
that refer to the BasicBlock's BlockAddress already referenced within
the solver.

To fix this:

1. Replace the `i8* blockaddress(@fn, %bb)` with `i8* inttoptr(i32 1 to i8*)`.
2. Find the ValueLatticeElements that may refer to the previous `BlockAddress`' `User`s.
3. Update those to use the new `IntToPtrInst` `Value`.

Fixes: https://github.com/llvm/llvm-project/issues/54238
Fixes: https://github.com/llvm/llvm-project/issues/54251


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D121744

Files:
  llvm/include/llvm/Transforms/Utils/SCCPSolver.h
  llvm/lib/Transforms/Scalar/SCCP.cpp
  llvm/lib/Transforms/Utils/SCCPSolver.cpp
  llvm/test/Transforms/SCCP/dangling-block-address.ll

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