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terms of cost rather than hoisting a single instruction. This does *not* change the cost model! We still set the cost threshold at 1 here, it's just that we track it by accumulating cost rather than by storing an instruction. The primary advantage is that we no longer leave no-op intrinsics in the basic block. For example, this will now move both debug info intrinsics and a single instruction, instead of only moving the instruction and leaving a basic block with nothing bug debug info intrinsics in it, and those intrinsics now no longer ordered correctly with the hoisted value. Instead, we now splice the entire conditional basic block's instruction sequence. This also places the code for checking the safety of hoisting next to the code computing the cost. Currently, the only observable side-effect of this change is that debug info intrinsics are no longer abandoned. I'm not sure how to craft a test case for this, and my real goal was the refactoring, but I'll talk to Dave or Eric about how to add a test case for this. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173339 91177308-0d34-0410-b5e6-96231b3b80d8
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