Don't add CFG edges for redundant conditional branches.

[oota-llvm.git] / lib / CodeGen / SelectionDAG / TargetLowering.cpp

diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 891d401201f2a5fd0a30dc77327ccdde8694c305..6820175c1bed9e825409821c0c38c0d8c47526b6 100644 (file)
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2303,7 +2303,7 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
         N0.getOpcode() == ISD::AND)
       if (ConstantSDNode *AndRHS =
                   dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
-        EVT ShiftTy = DCI.isBeforeLegalize() ?
+        EVT ShiftTy = DCI.isBeforeLegalizeOps() ?
           getPointerTy() : getShiftAmountTy(N0.getValueType());
         if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0  -->  (X & 8) >> 3
           // Perform the xform if the AND RHS is a single bit.
@@ -2322,6 +2322,55 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
           }
         }
       }
+
+    if (C1.getMinSignedBits() <= 64 &&
+        !isLegalICmpImmediate(C1.getSExtValue())) {
+      // (X & -256) == 256 -> (X >> 8) == 1
+      if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
+          N0.getOpcode() == ISD::AND && N0.hasOneUse()) {
+        if (ConstantSDNode *AndRHS =
+            dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
+          const APInt &AndRHSC = AndRHS->getAPIntValue();
+          if ((-AndRHSC).isPowerOf2() && (AndRHSC & C1) == C1) {
+            unsigned ShiftBits = AndRHSC.countTrailingZeros();
+            EVT ShiftTy = DCI.isBeforeLegalizeOps() ?
+              getPointerTy() : getShiftAmountTy(N0.getValueType());
+            EVT CmpTy = N0.getValueType();
+            SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0.getOperand(0),
+                                        DAG.getConstant(ShiftBits, ShiftTy));
+            SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), CmpTy);
+            return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond);
+          }
+        }
+      } else if (Cond == ISD::SETULT || Cond == ISD::SETUGE ||
+                 Cond == ISD::SETULE || Cond == ISD::SETUGT) {
+        bool AdjOne = (Cond == ISD::SETULE || Cond == ISD::SETUGT);
+        // X <  0x100000000 -> (X >> 32) <  1
+        // X >= 0x100000000 -> (X >> 32) >= 1
+        // X <= 0x0ffffffff -> (X >> 32) <  1
+        // X >  0x0ffffffff -> (X >> 32) >= 1
+        unsigned ShiftBits;
+        APInt NewC = C1;
+        ISD::CondCode NewCond = Cond;
+        if (AdjOne) {
+          ShiftBits = C1.countTrailingOnes();
+          NewC = NewC + 1;
+          NewCond = (Cond == ISD::SETULE) ? ISD::SETULT : ISD::SETUGE;
+        } else {
+          ShiftBits = C1.countTrailingZeros();
+        }
+        NewC = NewC.lshr(ShiftBits);
+        if (ShiftBits && isLegalICmpImmediate(NewC.getSExtValue())) {
+          EVT ShiftTy = DCI.isBeforeLegalizeOps() ?
+            getPointerTy() : getShiftAmountTy(N0.getValueType());
+          EVT CmpTy = N0.getValueType();
+          SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0,
+                                      DAG.getConstant(ShiftBits, ShiftTy));
+          SDValue CmpRHS = DAG.getConstant(NewC, CmpTy);
+          return DAG.getSetCC(dl, VT, Shift, CmpRHS, NewCond);
+        }
+      }
+    }
   }
 
   if (isa<ConstantFPSDNode>(N0.getNode())) {
@@ -2415,7 +2464,8 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
     // Otherwise, we can't fold it.  However, we can simplify it to SETUO/SETO
     // if it is not already.
     ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
-    if (NewCond != Cond)
+    if (NewCond != Cond && (DCI.isBeforeLegalizeOps() ||
+          getCondCodeAction(NewCond, N0.getValueType()) == Legal))
       return DAG.getSetCC(dl, VT, N0, N1, NewCond);
   }
 
@@ -2984,10 +3034,12 @@ TargetLowering::AsmOperandInfoVector TargetLowering::ParseConstraints(
       AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
 
       if (OpInfo.ConstraintVT != Input.ConstraintVT) {
-       std::pair<unsigned, const TargetRegisterClass*> MatchRC =
-         getRegForInlineAsmConstraint(OpInfo.ConstraintCode, OpInfo.ConstraintVT);
-       std::pair<unsigned, const TargetRegisterClass*> InputRC =
-         getRegForInlineAsmConstraint(Input.ConstraintCode, Input.ConstraintVT);
+        std::pair<unsigned, const TargetRegisterClass*> MatchRC =
+          getRegForInlineAsmConstraint(OpInfo.ConstraintCode,
+                                       OpInfo.ConstraintVT);
+        std::pair<unsigned, const TargetRegisterClass*> InputRC =
+          getRegForInlineAsmConstraint(Input.ConstraintCode,
+                                       Input.ConstraintVT);
         if ((OpInfo.ConstraintVT.isInteger() !=
              Input.ConstraintVT.isInteger()) ||
             (MatchRC.second != InputRC.second)) {