[NFC][RemoveDIs] Create a new spelling of the moveBefore method

As outlined in my proposal of how to get rid of debug intrinsics, this
patch adds a moveBefore method that signals the caller /intends/ the order
of moved instructions is to stay the same. This semantic difference has an
effect on debug-info, as it signals whether debug-info needs to move with
instructions or not.

The patch just replaces a few calls to moveBefore with calls to
moveBeforePreserving -- and the latter just calls the former, so it's all
NFC right now. A future patch will add an implementation of
moveBeforePreserving that takes action to correctly preserve debug-info,
but that's tightly coupled with our non-instruction debug-info
representation that's still being reviewed.

[0] https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939

Differential Revision: https://reviews.llvm.org/D156369

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 7edb4e9..629062d8 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -300,7 +300,7 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU,
     PredBB->back().eraseFromParent();
 
     // Move terminator instruction.
-    PredBB->splice(PredBB->end(), BB);
+    BB->back().moveBeforePreserving(*PredBB, PredBB->end());
 
     // Terminator may be a memory accessing instruction too.
     if (MSSAU)