[all-commits] [llvm/llvm-project] 9bbf3a: [IndVars] Add test for #126012 (NFC)

[Nikita Popov via All-commits]

  Branch: refs/heads/release/20.x
  Home:   https://github.com/llvm/llvm-project
  Commit: 9bbf3a98b793f8fc6269a20a026ca6fe029a1790
      https://github.com/llvm/llvm-project/commit/9bbf3a98b793f8fc6269a20a026ca6fe029a1790
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2025-02-11 (Tue, 11 Feb 2025)

  Changed paths:
    A llvm/test/Transforms/IndVarSimplify/pr126012.ll

  Log Message:
  -----------
  [IndVars] Add test for #126012 (NFC)

(cherry picked from commit ae08969a2068dd327fbf4d0f606550574fbb9e45)


  Commit: af970cd8753c37e7fcf66b6211f2a2d1e261325c
      https://github.com/llvm/llvm-project/commit/af970cd8753c37e7fcf66b6211f2a2d1e261325c
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2025-02-11 (Tue, 11 Feb 2025)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Transforms/IndVarSimplify/pr126012.ll

  Log Message:
  -----------
  [ScalarEvolution] Handle addrec incoming value in isImpliedViaMerge() (#126236)

The code already guards against values coming from a previous iteration
using properlyDominates(). However, addrecs are considered to properly
dominate the loop they are defined in.

Handle this special case separately, by checking for expressions that
have computable loop evolution (this should cover cases like a zext of
an addrec as well).

I considered changing the definition of properlyDominates() instead, but
decided against it. The current definition is useful in other context,
e.g. when deciding whether an expression is safe to expand in a given
block.

Fixes https://github.com/llvm/llvm-project/issues/126012.

(cherry picked from commit 7aed53eb1982113e825534f0f66d0a0e46e7a5ed)


Compare: https://github.com/llvm/llvm-project/compare/94c1a8ea1bfe...af970cd8753c

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