[PATCH] D149344: [SCEV] Replace IsAvailableOnEntry with block disposition

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

@manojgupta Thanks! Here's a somewhat reduced test case for `-passes=loop-idiom`:

  define void @test() {
  entry:
    %alloca = alloca [64 x i8], align 16
    br label %loop
  
  loop:
    %phi = phi i64 [ 0, %entry ], [ 1, %loop.latch ]
    br i1 false, label %loop.exit2, label %loop.latch
  
  loop.latch:
    %or = or i64 %phi, 4
    br i1 false, label %loop.exit, label %loop
  
  loop.exit:
    br label %loop2.preheader
  
  loop.exit2:
    br label %loop2.preheader
  
  loop2.preheader:
    %phi5.ph = phi ptr [ null, %loop.exit2 ], [ %alloca, %loop.exit ]
    %phi6.ph = phi i64 [ 0, %loop.exit2 ], [ %or, %loop.exit ]
    br label %loop2
  
  loop2:
    %phi5 = phi ptr [ %getelementptr7, %loop2 ], [ %phi5.ph, %loop2.preheader ]
    %phi6 = phi i64 [ %add, %loop2 ], [ %phi6.ph, %loop2.preheader ]
    %getelementptr = getelementptr i8, ptr %alloca, i64 %phi6
    %load = load i8, ptr %getelementptr, align 1
    store i8 %load, ptr %phi5, align 1
    %getelementptr7 = getelementptr i8, ptr %phi5, i64 1
    %add = add i64 %phi6, 1
    %icmp = icmp eq i64 %phi6, 0
    br i1 %icmp, label %loop2.exit, label %loop2
  
  loop2.exit:
    ret void
  }

Triggers this assertion:

> opt: /home/npopov/repos/llvm-project/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp:2673: void llvm::SCEVExpanderCleaner::cleanup(): Assertion `all_of(I->users(), [&InsertedSet](Value *U) { return InsertedSet.contains(cast<Instruction>(U)); }) && "removed instruction should only be used by instructions inserted " "during expansion"' failed.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D149344/new/

https://reviews.llvm.org/D149344