[PATCH] D58260: [INLINER] allow inlining of blockaddresses if sole uses are callbrs

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers added a comment.

@chandlerc alternatively, if I drop the posted changed to llvm/lib/Analysis/CGSCCPassManager.cpp and instead do:

  diff --git a/llvm/include/llvm/Analysis/LazyCallGraph.h b/llvm/include/llvm/Analysis/La
  zyCallGraph.h
  index 328654763b59..62e062a30718 100644
  --- a/llvm/include/llvm/Analysis/LazyCallGraph.h
  +++ b/llvm/include/llvm/Analysis/LazyCallGraph.h
  @@ -1082,12 +1082,21 @@ public:
           continue;
         }
   
  +      // The blockaddress constant expression is a weird special case, we can't
  +      // generically walk its operands the way we do for all other constants.
         if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
  -        // The blockaddress constant expression is a weird special case, we
  -        // can't generically walk its operands the way we do for all other
  -        // constants.
  +        bool AllUsersAreSameFn = true;
  +        for (User *U : BA->users())
  +          if (Instruction *I = dyn_cast<Instruction>(U))
  +            if (I->getFunction() != BA->getFunction()) {
  +              AllUsersAreSameFn = false;
  +              break;
  +            }
           if (Visited.insert(BA->getFunction()).second)
  -          Worklist.push_back(BA->getFunction());
  +          // If the blockaddress' function it refers to a function it's not
  +          // defined within, visit the other function.
  +          if (!AllUsersAreSameFn)
  +            Worklist.push_back(BA->getFunction());
           continue;
         }

This also works.  I *think* it's correct that we don't want to re-visit the function the blockaddress refers to, if it refers to the same function the blockaddress is within.  LazyCallGraphTest.HandleBlockAddress tests what happens with the blockaddress refers to a block outside the scope of the current function.


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https://reviews.llvm.org/D58260