Whitney Tsang 0ac56aa46f Ensure SplitEdge to return the new block between the two given blocks ... This PR implements the function splitBasicBlockBefore to address an issue that occurred during SplitEdge(BB, Succ, ...), inside splitBlockBefore. The issue occurs in SplitEdge when the Succ has a single predecessor and the edge between the BB and Succ is not critical. This produces the result ‘BB->Succ->New’. The new function splitBasicBlockBefore was added to splitBlockBefore to handle the issue and now produces the correct result ‘BB->New->Succ’. Below is an example of splitting the block bb1 at its first instruction. /// Original IR bb0: br bb1 bb1: %0 = mul i32 1, 2 br bb2 bb2: /// IR after splitEdge(bb0, bb1) using splitBasicBlock bb0: br bb1 bb1: br bb1.split bb1.split: %0 = mul i32 1, 2 br bb2 bb2: /// IR after splitEdge(bb0, bb1) using splitBasicBlockBefore bb0: br bb1.split bb1.split br bb1 bb1: %0 = mul i32 1, 2 br bb2 bb2: Differential Revision: https://reviews.llvm.org/D92200		2020-12-18 17:37:17 +00:00
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llvm	Ensure SplitEdge to return the new block between the two given blocks	2020-12-18 17:37:17 +00:00
llvm-c