[all-commits] [llvm/llvm-project] b9dc56: [GVN] Encode GEPs in offset representation

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b9dc5651477b4c3c132662e763308b27963248a9
      https://github.com/llvm/llvm-project/commit/b9dc5651477b4c3c132662e763308b27963248a9
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2022-04-28 (Thu, 28 Apr 2022)

  Changed paths:
    M llvm/include/llvm/Transforms/Scalar/GVN.h
    M llvm/lib/Transforms/Scalar/GVN.cpp
    M llvm/test/Transforms/GVN/opaque-ptr.ll

  Log Message:
  -----------
  [GVN] Encode GEPs in offset representation

When using opaque pointers, convert GEPs into offset representation
of the form P + V1 * Scale1 + V2 * Scale2 + ... + ConstantOffset.
This allows us to recognize equivalent address calculations even if
the GEPs don't use the same source element type.

This fixes an opaque pointer codegen regression seen in rustc.

Differential Revision: https://reviews.llvm.org/D124527