[PATCH] D152772: [LoopSink] Allow sinking to PHI-use

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added a comment.

  $ cat /tmp/a.ll
  target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
  target triple = "aarch64-grtev4-linux-gnu"
  
  %struct.blam = type { %struct.blam.0, [32 x i8] }
  %struct.blam.0 = type { ptr, i64 }
  
  define internal void @wibble() !prof !0 {
  bb:
    %getelementptr = getelementptr %struct.blam, ptr null, i64 0, i32 1
    br label %bb1
  
  bb1:                                              ; preds = %bb7, %bb3, %bb
    br i1 false, label %bb2, label %bb3
  
  bb2:                                              ; preds = %bb1
    ret void
  
  bb3:                                              ; preds = %bb4, %bb1
    switch i32 0, label %bb5 [
      i32 1, label %bb4
      i32 0, label %bb1
    ], !prof !1
  
  bb4:                                              ; preds = %bb3
    br i1 false, label %bb3, label %bb6
  
  bb5:                                              ; preds = %bb3
    br i1 false, label %bb6, label %bb7
  
  bb6:                                              ; preds = %bb5, %bb4
    br label %bb7
  
  bb7:                                              ; preds = %bb6, %bb5
    %phi = phi ptr [ null, %bb6 ], [ %getelementptr, %bb5 ]
    store ptr %getelementptr, ptr null, align 8
    br label %bb1
  }
  
  !0 = !{!"function_entry_count", i64 1}
  !1 = !{!"branch_weights", i32 1, i32 188894, i32 287400}
  $ opt -p loop-sink /tmp/a.ll
  Instruction does not dominate all uses!                                                                                                                                                                                                                                                   
    %getelementptr1 = getelementptr %struct.blam, ptr null, i64 0, i32 1                                                                                                                                                                                                                    
    %phi = phi ptr [ null, %bb6 ], [ %getelementptr1, %bb5 ]                                                                                                                                                                                                                                


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152772/new/

https://reviews.llvm.org/D152772