[all-commits] [llvm/llvm-project] ab8e33: [InstCombine] Pre-commit tests related to ADDLIKE+...

[Björn Pettersson via All-commits]

  Branch: refs/heads/users/bjope/addlikegep
  Home:   https://github.com/llvm/llvm-project
  Commit: ab8e330be6b3169a102a7655031b7a277fe75b81
      https://github.com/llvm/llvm-project/commit/ab8e330be6b3169a102a7655031b7a277fe75b81
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-10 (Thu, 10 Apr 2025)

  Changed paths:
    M llvm/test/Transforms/InstCombine/array.ll

  Log Message:
  -----------
  [InstCombine] Pre-commit tests related to ADDLIKE+GEP->GEP+GEP. NFC

InstCombine can transform ADD+GEP into GEP+GEP. But those rewrites
does not currently trigger when the ADD is a disjoint OR (which
happens to be the canonical form for certain ADD operations). Add
lit tests to show that we are lacking such rewrites.

Also add a test case showing that we do not preserve "inbounds nuw"
and "nuw" when doing such transforms and the ADD/OR is known to be
NUW.


  Commit: ed9952ed26a9e15edf2f83a75c220988c4c1928c
      https://github.com/llvm/llvm-project/commit/ed9952ed26a9e15edf2f83a75c220988c4c1928c
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-10 (Thu, 10 Apr 2025)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
    M llvm/test/Transforms/InstCombine/array.ll

  Log Message:
  -----------
  [InstCombine] Improve inbounds preservation for ADD+GEP -> GEP+GEP

Given that we have a "add nuw" and a "getelementptr inbounds nuw" like
this:
   %idx = add nuw i64 %idx1, %idx2
   %gep = getelementptr inbounds nuw i32, ptr %ptr, i64 %idx

Then we can preserve the "inbounds nuw" flag when transforming that
into two getelementptr instructions:
   %gep1 = getelementptr inbounds nuw i32, ptr %ptr, i64 %idx1
   %gep = getelementptr inbounds nuw i32, ptr %ptr, i64 %idx2

Similarly for just having "nuw" instead of "inbounds nuw" on the
getelementptr.

Proof: https://alive2.llvm.org/ce/z/4uhfDq


  Commit: 1df32f312cac7991adf830cb007008dffa26db47
      https://github.com/llvm/llvm-project/commit/1df32f312cac7991adf830cb007008dffa26db47
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-10 (Thu, 10 Apr 2025)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
    M llvm/test/Transforms/InstCombine/array.ll
    M llvm/test/Transforms/InstCombine/gep-merge-constant-indices.ll
    M llvm/test/Transforms/InstCombine/gep-vector.ll
    M llvm/test/Transforms/InstCombine/vscale_gep.ll
    M llvm/test/Transforms/LoopUnroll/runtime-multiexit-heuristic.ll
    M llvm/test/Transforms/LoopVectorize/ARM/mve-reductions.ll
    M llvm/test/Transforms/LoopVectorize/SystemZ/addressing.ll
    M llvm/test/Transforms/LoopVectorize/X86/float-induction-x86.ll
    M llvm/test/Transforms/LoopVectorize/X86/interleaving.ll
    M llvm/test/Transforms/LoopVectorize/X86/parallel-loops.ll
    M llvm/test/Transforms/LoopVectorize/X86/small-size.ll
    M llvm/test/Transforms/LoopVectorize/consecutive-ptr-uniforms.ll
    M llvm/test/Transforms/LoopVectorize/float-induction.ll
    M llvm/test/Transforms/LoopVectorize/forked-pointers.ll
    M llvm/test/Transforms/LoopVectorize/induction.ll
    M llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
    M llvm/test/Transforms/LoopVectorize/reduction-inloop-cond.ll
    M llvm/test/Transforms/LoopVectorize/reduction-inloop-pred.ll
    M llvm/test/Transforms/LoopVectorize/reduction-inloop-uf4.ll
    M llvm/test/Transforms/LoopVectorize/reduction-predselect.ll

  Log Message:
  -----------
  [InstCombine] Handle "add like" in ADD+GEP->GEP+GEP rewrites

Considering that "or disjoint" is that canonical for certain
add operations, then I think we want to support such "add like"
operations when doing ADD+GEP->GEP+GEP rewrites to make things
more consistent.


Compare: https://github.com/llvm/llvm-project/compare/ab8e330be6b3%5E...1df32f312cac

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