[all-commits] [llvm/llvm-project] 10c982: Revert rG1c9bec727ab5c53fa060560dc8d346a911142170 ...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 10c982e0b3e6d46d1fe288d7dbe0a393c65a640f
      https://github.com/llvm/llvm-project/commit/10c982e0b3e6d46d1fe288d7dbe0a393c65a640f
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-08-23 (Mon, 23 Aug 2021)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
    M llvm/test/Transforms/InstCombine/gep-combine-loop-invariant.ll
    M llvm/test/Transforms/InstCombine/gep-custom-dl.ll
    M llvm/test/Transforms/InstCombine/getelementptr.ll
    M llvm/test/Transforms/InstCombine/select-gep.ll
    M llvm/test/Transforms/InstCombine/shift.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/sve-vector-reverse.ll
    M llvm/test/Transforms/LoopVectorize/AArch64/vector-reverse-mask4.ll
    M llvm/test/Transforms/LoopVectorize/ARM/mve-reductions.ll
    M llvm/test/Transforms/LoopVectorize/X86/x86-interleaved-accesses-masked-group.ll
    M llvm/test/Transforms/LoopVectorize/X86/x86-interleaved-store-accesses-with-gaps.ll
    M llvm/test/Transforms/LoopVectorize/consecutive-ptr-uniforms.ll
    M llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll

  Log Message:
  -----------
  Revert rG1c9bec727ab5c53fa060560dc8d346a911142170 : [InstCombine] Fold (gep (oneuse(gep Ptr, Idx0)), Idx1) -> (gep Ptr, (add Idx0, Idx1)) (PR51069)

Reverted (manually due to merge conflicts) while regressions reported on PR51540 are investigated

As noticed on D106352, after we've folded "(select C, (gep Ptr, Idx), Ptr) -> (gep Ptr, (select C, Idx, 0))" if the inner Ptr was also a (now one use) gep we could then merge the geps, using the sum of the indices instead.

I've limited this to basic 2-op geps - a more general case further down InstCombinerImpl.visitGetElementPtrInst doesn't have the one-use limitation but only creates the add if it can be created via SimplifyAddInst.

https://alive2.llvm.org/ce/z/f8pLfD (Thanks Roman!)

Differential Revision: https://reviews.llvm.org/D106450