[DAG] Pull out ComputeNumSignBits call to make debugging easier. NFCI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357861 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 8796888c7e5012168caddf2ce5993ab98ffcc4ea..5b89aceb9d4b3752da246f27def1678599811ae9 100644 (file)
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1130,8 +1130,8 @@ bool TargetLowering::SimplifyDemandedBits(
 
     // If we only care about the highest bit, don't bother shifting right.
     if (DemandedBits.isSignMask()) {
-      bool AlreadySignExtended =
-          TLO.DAG.ComputeNumSignBits(Op0) >= BitWidth - ExVTBits + 1;
+      unsigned NumSignBits = TLO.DAG.ComputeNumSignBits(Op0);
+      bool AlreadySignExtended = NumSignBits >= BitWidth - ExVTBits + 1;
       // However if the input is already sign extended we expect the sign
       // extension to be dropped altogether later and do not simplify.
       if (!AlreadySignExtended) {