[all-commits] [llvm/llvm-project] 84108e: [InstCombine] Improve no-wrap flag preservation fo...

[Björn Pettersson via All-commits]

  Branch: refs/heads/users/bjope/addlikegep_2
  Home:   https://github.com/llvm/llvm-project
  Commit: 84108e55aa15eeabc634671fdf7b8170d0667912
      https://github.com/llvm/llvm-project/commit/84108e55aa15eeabc634671fdf7b8170d0667912
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-11 (Fri, 11 Apr 2025)

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

  Log Message:
  -----------
  [InstCombine] Improve no-wrap flag 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" or "nusw nuw" instead of "inbounds nuw"
on the getelementptr.

Proof: https://alive2.llvm.org/ce/z/QSweWW


  Commit: 9b57d63a57843ca5f0ab7c8466eb5e33b0788b89
      https://github.com/llvm/llvm-project/commit/9b57d63a57843ca5f0ab7c8466eb5e33b0788b89
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-11 (Fri, 11 Apr 2025)

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

  Log Message:
  -----------
  Fixups after review feedback:

- Make sure we try to derive inbound + nuw before doing the
  ADD+GEP->GEP+GEP rewrites. This to make it possible to rely
  on "nuw" being present when trying to preserve flags.

- Make sure the special ADDNSW+SEXTLIKE+GEP->GEP+GEP case is checking
  for ADDNUW+ZEXTNNEG+GEP->GEP+GEP when preserving flags.
  This way we do not need to check for non-negative operands.


  Commit: 6f9a251e5fa149fc9d7d262c7aac077e4651aa4e
      https://github.com/llvm/llvm-project/commit/6f9a251e5fa149fc9d7d262c7aac077e4651aa4e
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-11 (Fri, 11 Apr 2025)

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

  Log Message:
  -----------
  Fix clang-format


  Commit: cc91c585be1681f4eb6b0f91382bf343139a88d1
      https://github.com/llvm/llvm-project/commit/cc91c585be1681f4eb6b0f91382bf343139a88d1
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-11 (Fri, 11 Apr 2025)

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

  Log Message:
  -----------
  Fixup


  Commit: 51ec9b0ab4799faad383e8b32c006cf1f49cf9e1
      https://github.com/llvm/llvm-project/commit/51ec9b0ab4799faad383e8b32c006cf1f49cf9e1
  Author: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>
  Date:   2025-04-11 (Fri, 11 Apr 2025)

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

  Log Message:
  -----------
  Fixup: Also handle "nusw nuw"


Compare: https://github.com/llvm/llvm-project/compare/4895b27ac166...51ec9b0ab479

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