[Instruction] add moveAfter() convenience function; NFCI

As suggested in D37121, here's a wrapper for removeFromParent() + insertAfter(),
but implemented using moveBefore() for symmetry/efficiency.

Differential Revision: https://reviews.llvm.org/D37239

llvm-svn: 312001

1 files changed, 2 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/AtomicExpandPass.cpp b/llvm/lib/CodeGen/AtomicExpandPass.cpp
index aa9c8e94d08..9d1f94a8a43 100644
--- a/llvm/lib/CodeGen/AtomicExpandPass.cpp
+++ b/llvm/lib/CodeGen/AtomicExpandPass.cpp
@@ -320,16 +320,10 @@ bool AtomicExpand::bracketInstWithFences(Instruction *I, AtomicOrdering Order) {
   auto LeadingFence = TLI->emitLeadingFence(Builder, I, Order);
 
   auto TrailingFence = TLI->emitTrailingFence(Builder, I, Order);
-  // The trailing fence is emitted before the instruction instead of after
-  // because there is no easy way of setting Builder insertion point after
-  // an instruction. So we must erase it from the BB, and insert it back
-  // in the right place.
   // We have a guard here because not every atomic operation generates a
   // trailing fence.
-  if (TrailingFence) {
-    TrailingFence->removeFromParent();
-    TrailingFence->insertAfter(I);
-  }
+  if (TrailingFence)
+    TrailingFence->moveAfter(I);
 
   return (LeadingFence || TrailingFence);
 }