Implement ctlz and cttz with bsr and bsf.
llvm-svn: 45024
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 07e19aa..1d64b1d 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -210,18 +210,18 @@
setOperationAction(ISD::FLT_ROUNDS , MVT::i32 , Custom);
setOperationAction(ISD::CTPOP , MVT::i8 , Expand);
- setOperationAction(ISD::CTTZ , MVT::i8 , Expand);
- setOperationAction(ISD::CTLZ , MVT::i8 , Expand);
+ setOperationAction(ISD::CTTZ , MVT::i8 , Custom);
+ setOperationAction(ISD::CTLZ , MVT::i8 , Custom);
setOperationAction(ISD::CTPOP , MVT::i16 , Expand);
- setOperationAction(ISD::CTTZ , MVT::i16 , Expand);
- setOperationAction(ISD::CTLZ , MVT::i16 , Expand);
+ setOperationAction(ISD::CTTZ , MVT::i16 , Custom);
+ setOperationAction(ISD::CTLZ , MVT::i16 , Custom);
setOperationAction(ISD::CTPOP , MVT::i32 , Expand);
- setOperationAction(ISD::CTTZ , MVT::i32 , Expand);
- setOperationAction(ISD::CTLZ , MVT::i32 , Expand);
+ setOperationAction(ISD::CTTZ , MVT::i32 , Custom);
+ setOperationAction(ISD::CTLZ , MVT::i32 , Custom);
if (Subtarget->is64Bit()) {
setOperationAction(ISD::CTPOP , MVT::i64 , Expand);
- setOperationAction(ISD::CTTZ , MVT::i64 , Expand);
- setOperationAction(ISD::CTLZ , MVT::i64 , Expand);
+ setOperationAction(ISD::CTTZ , MVT::i64 , Custom);
+ setOperationAction(ISD::CTLZ , MVT::i64 , Custom);
}
setOperationAction(ISD::READCYCLECOUNTER , MVT::i64 , Custom);
@@ -5345,6 +5345,42 @@
ISD::TRUNCATE : ISD::ZERO_EXTEND), VT, RetVal);
}
+SDOperand X86TargetLowering::LowerCTLZ(SDOperand Op, SelectionDAG &DAG) {
+ MVT::ValueType VT = Op.getValueType();
+ MVT::ValueType OpVT = VT;
+ unsigned NumBits = MVT::getSizeInBits(VT);
+
+ Op = Op.getOperand(0);
+ if (VT == MVT::i8) {
+ OpVT = MVT::i32;
+ Op = DAG.getNode(ISD::ZERO_EXTEND, OpVT, Op);
+ }
+ if (VT == MVT::i32 || VT == MVT::i64)
+ return DAG.getNode(ISD::XOR, OpVT, DAG.getNode(X86ISD::BSR, OpVT, Op),
+ DAG.getConstant(NumBits-1, OpVT));
+
+ Op = DAG.getNode(ISD::SUB, OpVT, DAG.getConstant(NumBits-1, OpVT),
+ DAG.getNode(X86ISD::BSR, OpVT, Op));
+ if (VT == MVT::i8)
+ Op = DAG.getNode(ISD::TRUNCATE, MVT::i8, Op);
+ return Op;
+}
+
+SDOperand X86TargetLowering::LowerCTTZ(SDOperand Op, SelectionDAG &DAG) {
+ MVT::ValueType VT = Op.getValueType();
+ MVT::ValueType OpVT = VT;
+
+ Op = Op.getOperand(0);
+ if (VT == MVT::i8) {
+ OpVT = MVT::i32;
+ Op = DAG.getNode(ISD::ZERO_EXTEND, OpVT, Op);
+ }
+ Op = DAG.getNode(X86ISD::BSF, OpVT, Op);
+ if (VT == MVT::i8)
+ Op = DAG.getNode(ISD::TRUNCATE, MVT::i8, Op);
+ return Op;
+}
+
/// LowerOperation - Provide custom lowering hooks for some operations.
///
SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
@@ -5387,7 +5423,8 @@
case ISD::EH_RETURN: return LowerEH_RETURN(Op, DAG);
case ISD::TRAMPOLINE: return LowerTRAMPOLINE(Op, DAG);
case ISD::FLT_ROUNDS: return LowerFLT_ROUNDS(Op, DAG);
-
+ case ISD::CTLZ: return LowerCTLZ(Op, DAG);
+ case ISD::CTTZ: return LowerCTTZ(Op, DAG);
// FIXME: REMOVE THIS WHEN LegalizeDAGTypes lands.
case ISD::READCYCLECOUNTER:
@@ -5407,6 +5444,8 @@
const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (Opcode) {
default: return NULL;
+ case X86ISD::BSF: return "X86ISD::BSF";
+ case X86ISD::BSR: return "X86ISD::BSR";
case X86ISD::SHLD: return "X86ISD::SHLD";
case X86ISD::SHRD: return "X86ISD::SHRD";
case X86ISD::FAND: return "X86ISD::FAND";