[all-commits] [llvm/llvm-project] a4a9b6: [SimplifyCFG] Handle degenerate conditional branch...

[Yingwei Zheng via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a4a9b6864c6f185500f08a5a037d93b5e67657dc
      https://github.com/llvm/llvm-project/commit/a4a9b6864c6f185500f08a5a037d93b5e67657dc
  Author: Yingwei Zheng <dtcxzyw2333 at gmail.com>
  Date:   2026-07-28 (Tue, 28 Jul 2026)

  Changed paths:
    M llvm/lib/Transforms/Utils/SimplifyCFG.cpp
    M llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll

  Log Message:
  -----------
  [SimplifyCFG] Handle degenerate conditional branch (#212552)

IR before entering the function:
```
define void @func(i1 %cond) {
entry:
  br i1 %cond, label %exit, label %exit

exit:                                             ; preds = %entry, %entry
  %phi = phi i1 [ false, %entry ], [ false, %entry ]
  tail call void @llvm.assume(i1 %phi)
  ret void
}
```
The original code only removes one edge. There is still an edge from
entry to exit, triggering the `Deleted edge still exists in the CFG`
assertion.

Closes https://github.com/llvm/llvm-project/issues/212542



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