[all-commits] [llvm/llvm-project] 913513: [llvm-diff] Precommit: Add loop test case with for...

[Jannik Silvanus via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9135137718bbb8322dc42a1026ce3f843bbeacc6
      https://github.com/llvm/llvm-project/commit/9135137718bbb8322dc42a1026ce3f843bbeacc6
  Author: Jannik Silvanus <jannik.silvanus at amd.com>
  Date:   2022-11-03 (Thu, 03 Nov 2022)

  Changed paths:
    A llvm/test/tools/llvm-diff/loop.ll

  Log Message:
  -----------
  [llvm-diff] Precommit: Add loop test case with forward reference

Diffing phi nodes was recently added to llvm-diff.
However, there currently is a limitation where equivalent values
cannot be detected as such, leading to false positive diff reports.

If a phi node refers a value defined in a basic block dominated by
the current basic block, for example a phi node in a loop header referring
a value defined in the loop body, we cannot prove equivalence of the referred
values, because the basic block containing the variable definition has
not yet been processed.

This commit adds a test case showing this behavior, serving as a precommit
for an upcoming fix of the above.

Differential Revision: https://reviews.llvm.org/D137262