[llvm] r267331 - [X86] Merge LowerCTLZ and LowerCTLZ_ZERO_UNDEF into a single function that branches internally for the one difference, allowing the rest of the code to be common. NFC

[Craig Topper via llvm-commits]

Author: ctopper
Date: Sun Apr 24 01:27:39 2016
New Revision: 267331

URL: http://llvm.org/viewvc/llvm-project?rev=267331&view=rev
Log:
[X86] Merge LowerCTLZ and LowerCTLZ_ZERO_UNDEF into a single function that branches internally for the one difference, allowing the rest of the code to be common. NFC

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=267331&r1=267330&r2=267331&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Sun Apr 24 01:27:39 2016
@@ -18661,6 +18661,7 @@ SDValue X86TargetLowering::LowerFLT_ROUN
 //    split the vector, perform operation on it's Lo a Hi part and
 //    concatenate the results.
 static SDValue LowerVectorCTLZ_AVX512(SDValue Op, SelectionDAG &DAG) {
+  assert(Op.getOpcode() == ISD::CTLZ);
   SDLoc dl(Op);
   MVT VT = Op.getSimpleValueType();
   MVT EltVT = VT.getVectorElementType();
@@ -18691,8 +18692,8 @@ static SDValue LowerVectorCTLZ_AVX512(SD
     std::tie(Lo, Hi) = DAG.SplitVector(Op.getOperand(0), dl);
     MVT OutVT = MVT::getVectorVT(EltVT, NumElems/2);
 
-    Lo = DAG.getNode(Op.getOpcode(), dl, OutVT, Lo);
-    Hi = DAG.getNode(Op.getOpcode(), dl, OutVT, Hi);
+    Lo = DAG.getNode(ISD::CTLZ, dl, OutVT, Lo);
+    Hi = DAG.getNode(ISD::CTLZ, dl, OutVT, Hi);
 
     return DAG.getNode(ISD::CONCAT_VECTORS, dl, VT, Lo, Hi);
   }
@@ -18716,6 +18717,7 @@ static SDValue LowerCTLZ(SDValue Op, Sel
   MVT OpVT = VT;
   unsigned NumBits = VT.getSizeInBits();
   SDLoc dl(Op);
+  unsigned Opc = Op.getOpcode();
 
   if (VT.isVector())
     return LowerVectorCTLZ_AVX512(Op, DAG);
@@ -18731,42 +18733,18 @@ static SDValue LowerCTLZ(SDValue Op, Sel
   SDVTList VTs = DAG.getVTList(OpVT, MVT::i32);
   Op = DAG.getNode(X86ISD::BSR, dl, VTs, Op);
 
-  // If src is zero (i.e. bsr sets ZF), returns NumBits.
-  SDValue Ops[] = {
-    Op,
-    DAG.getConstant(NumBits + NumBits - 1, dl, OpVT),
-    DAG.getConstant(X86::COND_E, dl, MVT::i8),
-    Op.getValue(1)
-  };
-  Op = DAG.getNode(X86ISD::CMOV, dl, OpVT, Ops);
-
-  // Finally xor with NumBits-1.
-  Op = DAG.getNode(ISD::XOR, dl, OpVT, Op,
-                   DAG.getConstant(NumBits - 1, dl, OpVT));
-
-  if (VT == MVT::i8)
-    Op = DAG.getNode(ISD::TRUNCATE, dl, MVT::i8, Op);
-  return Op;
-}
-
-static SDValue LowerCTLZ_ZERO_UNDEF(SDValue Op, SelectionDAG &DAG) {
-  MVT VT = Op.getSimpleValueType();
-  EVT OpVT = VT;
-  unsigned NumBits = VT.getSizeInBits();
-  SDLoc dl(Op);
-
-  Op = Op.getOperand(0);
-  if (VT == MVT::i8) {
-    // Zero extend to i32 since there is not an i8 bsr.
-    OpVT = MVT::i32;
-    Op = DAG.getNode(ISD::ZERO_EXTEND, dl, OpVT, Op);
+  if (Opc == ISD::CTLZ) {
+    // If src is zero (i.e. bsr sets ZF), returns NumBits.
+    SDValue Ops[] = {
+      Op,
+      DAG.getConstant(NumBits + NumBits - 1, dl, OpVT),
+      DAG.getConstant(X86::COND_E, dl, MVT::i8),
+      Op.getValue(1)
+    };
+    Op = DAG.getNode(X86ISD::CMOV, dl, OpVT, Ops);
   }
 
-  // Issue a bsr (scan bits in reverse).
-  SDVTList VTs = DAG.getVTList(OpVT, MVT::i32);
-  Op = DAG.getNode(X86ISD::BSR, dl, VTs, Op);
-
-  // And xor with NumBits-1.
+  // Finally xor with NumBits-1.
   Op = DAG.getNode(ISD::XOR, dl, OpVT, Op,
                    DAG.getConstant(NumBits - 1, dl, OpVT));
 
@@ -21270,8 +21248,8 @@ SDValue X86TargetLowering::LowerOperatio
   case ISD::INIT_TRAMPOLINE:    return LowerINIT_TRAMPOLINE(Op, DAG);
   case ISD::ADJUST_TRAMPOLINE:  return LowerADJUST_TRAMPOLINE(Op, DAG);
   case ISD::FLT_ROUNDS_:        return LowerFLT_ROUNDS_(Op, DAG);
-  case ISD::CTLZ:               return LowerCTLZ(Op, DAG);
-  case ISD::CTLZ_ZERO_UNDEF:    return LowerCTLZ_ZERO_UNDEF(Op, DAG);
+  case ISD::CTLZ:
+  case ISD::CTLZ_ZERO_UNDEF:    return LowerCTLZ(Op, DAG);
   case ISD::CTTZ:
   case ISD::CTTZ_ZERO_UNDEF:    return LowerCTTZ(Op, DAG);
   case ISD::MUL:                return LowerMUL(Op, Subtarget, DAG);