tBfar is bl, which clobbers LR.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78370 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index 9b54e67..c95b1d6 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -253,6 +253,7 @@
                    "b $target", [(br bb:$target)]>;
 
   // Far jump
+  let Defs = [LR] in
   def tBfar : TIx2<(outs), (ins brtarget:$target), IIC_Br, 
                     "bl $target\t@ far jump",[]>;