[PATCH] D103959: [LoopDeletion] Handle Phis with similar inputs from different block

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added a comment.

Ok, we stepped on a loop that doesn't have a predecessor (I didn't even know it's possible). Reduced IR repro:

  opt -S -loop-deletion
  
  target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
  target triple = "aarch64-unknown-linux-gnu"
  
  define dso_local i32 @hoge() local_unnamed_addr #0 {
  bb:
    callbr void asm sideeffect "", "X"(i8* blockaddress(@hoge, %bb2)) #1
            to label %bb1 [label %bb2]
  
  bb1:                                              ; preds = %bb
    br label %bb2
  
  bb2:                                              ; preds = %bb2, %bb1, %bb
    %tmp = phi i32 [ undef, %bb1 ], [ %tmp3, %bb2 ], [ undef, %bb ]
    %tmp3 = tail call i32 bitcast (i32 (...)* @widget to i32 (i32)*)(i32 %tmp) #1
    br label %bb2
  }
  
  declare dso_local i32 @widget(...) local_unnamed_addr #0

Failure was exposed, but no caused by this patch. I will land a fix and then return this one.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D103959/new/

https://reviews.llvm.org/D103959