[PATCH] D146792: [LoopPredication] Do not sink conditions to branches. PR61673

[Anna Thomas via Phabricator via llvm-commits]

anna added inline comments.


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Comment at: llvm/lib/Transforms/Scalar/LoopPredication.cpp:1188
 
-  // Subtlety: We need to avoid inserting additional uses of the WC.  We know
-  // that it can only have one transitive use at the moment, and thus moving
-  // that use to just before the branch and inserting code before it and then
-  // modifying the operand is legal.
-  auto *IP = cast<Instruction>(WidenableBR->getCondition());
-  // Here we unconditionally modify the IR, so after this point we should return
-  // only `true`!
-  IP->moveBefore(WidenableBR);
-  if (MSSAU)
-    if (auto *MUD = MSSAU->getMemorySSA()->getMemoryAccess(IP))
-       MSSAU->moveToPlace(MUD, WidenableBR->getParent(),
-                          MemorySSA::BeforeTerminator);
-  Rewriter.setInsertPoint(IP);
-  IRBuilder<> B(IP);
+  Rewriter.setInsertPoint(WidenableBR);
+  IRBuilder<> B(WidenableBR);
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We should not widen at the branch, but rather at the widenable call. This is handled in the patch referenced above. 


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