br-identical.ll 657 B

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  1. ; RUN: opt -gvn -S -o - %s | FileCheck %s
  2. ; If a branch has two identical successors, we cannot declare either dead.
  3. define void @widget(i1 %p) {
  4. entry:
  5. br label %bb2
  6. bb2:
  7. %t1 = phi i64 [ 0, %entry ], [ %t5, %bb7 ]
  8. %t2 = add i64 %t1, 1
  9. %t3 = icmp ult i64 0, %t2
  10. br i1 %t3, label %bb3, label %bb4
  11. bb3:
  12. %t4 = call i64 @f()
  13. br label %bb4
  14. bb4:
  15. ; CHECK-NOT: phi {{.*}} undef
  16. %foo = phi i64 [ %t4, %bb3 ], [ 0, %bb2 ]
  17. br i1 %p, label %bb5, label %bb6
  18. bb5:
  19. br i1 true, label %bb7, label %bb7
  20. bb6:
  21. br i1 true, label %bb7, label %bb7
  22. bb7:
  23. %t5 = add i64 %t1, 1
  24. br i1 %p, label %bb2, label %bb8
  25. bb8:
  26. ret void
  27. }
  28. declare i64 @f()