1 files changed, 17 insertions, 23 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 4a94d351b98..ff6358b442a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2622,11 +2622,17 @@ void SelectionDAGBuilder::visitBitTestHeader(BitTestBlock &B,
   // Subtract the minimum value.
   SDValue SwitchOp = getValue(B.SValue);
   EVT VT = SwitchOp.getValueType();
-  SDValue RangeSub =
-      DAG.getNode(ISD::SUB, dl, VT, SwitchOp, DAG.getConstant(B.First, dl, VT));
+  SDValue Sub = DAG.getNode(ISD::SUB, dl, VT, SwitchOp,
+                            DAG.getConstant(B.First, dl, VT));
 
-  // Determine the type of the test operands.
+  // Check range.
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+  SDValue RangeCmp = DAG.getSetCC(
+      dl, TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(),
+                                 Sub.getValueType()),
+      Sub, DAG.getConstant(B.Range, dl, VT), ISD::SETUGT);
+
+  // Determine the type of the test operands.
   bool UsePtrType = false;
   if (!TLI.isTypeLegal(VT)) {
     UsePtrType = true;
@@ -2639,7 +2645,6 @@ void SelectionDAGBuilder::visitBitTestHeader(BitTestBlock &B,
         break;
       }
   }
-  SDValue Sub = RangeSub;
   if (UsePtrType) {
     VT = TLI.getPointerTy(DAG.getDataLayout());
     Sub = DAG.getZExtOrTrunc(Sub, dl, VT);
@@ -2655,24 +2660,16 @@ void SelectionDAGBuilder::visitBitTestHeader(BitTestBlock &B,
   addSuccessorWithProb(SwitchBB, MBB, B.Prob);
   SwitchBB->normalizeSuccProbs();
 
-  SDValue Root = CopyTo;
-  if (!B.OmitRangeCheck) {
-    // Conditional branch to the default block.
-    SDValue RangeCmp = DAG.getSetCC(dl,
-        TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(),
-                               RangeSub.getValueType()),
-        RangeSub, DAG.getConstant(B.Range, dl, RangeSub.getValueType()),
-        ISD::SETUGT);
-
-    Root = DAG.getNode(ISD::BRCOND, dl, MVT::Other, Root, RangeCmp,
-                       DAG.getBasicBlock(B.Default));
-  }
+  SDValue BrRange = DAG.getNode(ISD::BRCOND, dl,
+                                MVT::Other, CopyTo, RangeCmp,
+                                DAG.getBasicBlock(B.Default));
 
   // Avoid emitting unnecessary branches to the next block.
   if (MBB != NextBlock(SwitchBB))
-    Root = DAG.getNode(ISD::BR, dl, MVT::Other, Root, DAG.getBasicBlock(MBB));
+    BrRange = DAG.getNode(ISD::BR, dl, MVT::Other, BrRange,
+                          DAG.getBasicBlock(MBB));
 
-  DAG.setRoot(Root);
+  DAG.setRoot(BrRange);
 }
 
 /// visitBitTestCase - this function produces one "bit test"
@@ -10167,6 +10164,8 @@ void SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
         break;
       }
       case CC_BitTests: {
+        // FIXME: If Fallthrough is unreachable, skip the range check.
+
         // FIXME: Optimize away range check based on pivot comparisons.
         BitTestBlock *BTB = &SL->BitTestCases[I->BTCasesIndex];
 
@@ -10187,11 +10186,6 @@ void SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
           BTB->DefaultProb -= DefaultProb / 2;
         }
 
-        if (FallthroughUnreachable) {
-          // Skip the range check if the fallthrough block is unreachable.
-          BTB->OmitRangeCheck = true;
-        }
-
         // If we're in the right place, emit the bit test header right now.
         if (CurMBB == SwitchMBB) {
           visitBitTestHeader(*BTB, SwitchMBB);