[PATCH] D22001: [DSE] Remove dead stores in end blocks containing fence

Anna Thomas via llvm-commits llvm-commits at lists.llvm.org
Thu Jul 7 13:28:01 PDT 2016

anna marked 2 inline comments as done.
anna added a comment.

In http://reviews.llvm.org/D22001#477281, @dexonsmith wrote:

> I still think this should be the version of `isa<>` that takes a reference.

Yes, I've changed it to directly take the reference (as done in other dyn_cast checks such as `LoadInst`, `MemTransferInst`  just below the fenceInst check).

  if (isa<FenceInst>(BBI))

It's better to have it as a reference, as the same is done in all other checks for `BBI`.

The implicit conversion cost as stated in the lang ref:
Unfortunately, these implicit conversions come at a cost; they prevent these iterators from conforming to standard iterator conventions, and thus from being usable with standard algorithms and containers. For example, they prevent the following code, where B is a BasicBlock, from compiling:

llvm::SmallVector<llvm::Instruction *, 16>(B->begin(), B->end());
Because of this, these implicit conversions may be removed some day, and operator* changed to return a pointer instead of a reference.


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