SILInliner: Unconditional branches are essentially free.

Author: atrick

lib/SILOptimizer/Utils/SILInliner.cpp

@@ -789,6 +789,10 @@ InlineCost swift::instructionInlineCost(SILInstruction &I) {
   case SILInstructionKind::GetAsyncContinuationInst:
     return InlineCost::Free;
 
+  // Unconditional branch is free.
+  case SILInstructionKind::BranchInst:
+    return InlineCost::Free;
+
   case SILInstructionKind::AbortApplyInst:
   case SILInstructionKind::ApplyInst:
   case SILInstructionKind::TryApplyInst:
@@ -804,7 +808,6 @@ InlineCost swift::instructionInlineCost(SILInstruction &I) {
   case SILInstructionKind::WitnessMethodInst:
   case SILInstructionKind::AssignInst:
   case SILInstructionKind::AssignByWrapperInst:
-  case SILInstructionKind::BranchInst:
   case SILInstructionKind::CheckedCastBranchInst:
   case SILInstructionKind::CheckedCastValueBranchInst:
   case SILInstructionKind::CheckedCastAddrBranchInst: