[mips] Improve instruction selection for pattern (store (fp_to_sint $src), $ptr).

Previously, three instructions were needed:

trunc.w.s $f0, $f2
mfc1 $4, $f0
sw $4, 0($2)

Now we need only two:

trunc.w.s $f0, $f2
swc1 $f0, 0($2)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182053 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 40 insertions, 9 deletions

diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index ed62da5ecb..b344ddabc9 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -156,6 +156,7 @@ const char *MipsTargetLowering::getTargetNodeName(unsigned Opcode) const {
   case MipsISD::FPCmp:             return "MipsISD::FPCmp";
   case MipsISD::CMovFP_T:          return "MipsISD::CMovFP_T";
   case MipsISD::CMovFP_F:          return "MipsISD::CMovFP_F";
+  case MipsISD::TruncIntFP:        return "MipsISD::TruncIntFP";
   case MipsISD::ExtractLOHI:       return "MipsISD::ExtractLOHI";
   case MipsISD::InsertLOHI:        return "MipsISD::InsertLOHI";
   case MipsISD::Mult:              return "MipsISD::Mult";
@@ -249,6 +250,7 @@ MipsTargetLowering(MipsTargetMachine &TM)
   setOperationAction(ISD::VASTART,            MVT::Other, Custom);
   setOperationAction(ISD::FCOPYSIGN,          MVT::f32,   Custom);
   setOperationAction(ISD::FCOPYSIGN,          MVT::f64,   Custom);
+  setOperationAction(ISD::FP_TO_SINT,         MVT::i32,   Custom);
 
   if (!TM.Options.NoNaNsFPMath) {
     setOperationAction(ISD::FABS,             MVT::f32,   Custom);
@@ -264,6 +266,7 @@ MipsTargetLowering(MipsTargetMachine &TM)
     setOperationAction(ISD::SELECT,             MVT::i64,   Custom);
     setOperationAction(ISD::LOAD,               MVT::i64,   Custom);
     setOperationAction(ISD::STORE,              MVT::i64,   Custom);
+    setOperationAction(ISD::FP_TO_SINT,         MVT::i64,   Custom);
   }
 
   if (!HasMips64) {
@@ -743,6 +746,7 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const
   case ISD::LOAD:               return lowerLOAD(Op, DAG);
   case ISD::STORE:              return lowerSTORE(Op, DAG);
   case ISD::ADD:                return lowerADD(Op, DAG);
+  case ISD::FP_TO_SINT:         return lowerFP_TO_SINT(Op, DAG);
   }
   return SDValue();
 }
@@ -2027,6 +2031,22 @@ static SDValue lowerUnalignedIntStore(StoreSDNode *SD, SelectionDAG &DAG,
   return createStoreLR(MipsISD::SDR, DAG, SD, SDL, IsLittle ? 0 : 7);
 }
 
+// Lower (store (fp_to_sint $fp) $ptr) to (store (TruncIntFP $fp), $ptr).
+static SDValue lowerFP_TO_SINT_STORE(StoreSDNode *SD, SelectionDAG &DAG) {
+  SDValue Val = SD->getValue();
+
+  if (Val.getOpcode() != ISD::FP_TO_SINT)
+    return SDValue();
+
+  EVT FPTy = EVT::getFloatingPointVT(Val.getValueSizeInBits());
+  SDValue Tr = DAG.getNode(MipsISD::TruncIntFP, Val.getDebugLoc(), FPTy,
+                           Val.getOperand(0));
+
+  return DAG.getStore(SD->getChain(), SD->getDebugLoc(), Tr, SD->getBasePtr(),
+                      SD->getPointerInfo(), SD->isVolatile(),
+                      SD->isNonTemporal(), SD->getAlignment());
+}
+
 SDValue MipsTargetLowering::lowerSTORE(SDValue Op, SelectionDAG &DAG) const {
   StoreSDNode *SD = cast<StoreSDNode>(Op);
   EVT MemVT = SD->getMemoryVT();
@@ -2036,7 +2056,7 @@ SDValue MipsTargetLowering::lowerSTORE(SDValue Op, SelectionDAG &DAG) const {
       ((MemVT == MVT::i32) || (MemVT == MVT::i64)))
     return lowerUnalignedIntStore(SD, DAG, Subtarget->isLittle());
 
-  return SDValue();
+  return lowerFP_TO_SINT_STORE(SD, DAG);
 }
 
 SDValue MipsTargetLowering::lowerADD(SDValue Op, SelectionDAG &DAG) const {
@@ -2060,6 +2080,14 @@ SDValue MipsTargetLowering::lowerADD(SDValue Op, SelectionDAG &DAG) const {
                      DAG.getConstant(0, ValTy));
 }
 
+SDValue MipsTargetLowering::lowerFP_TO_SINT(SDValue Op,
+                                            SelectionDAG &DAG) const {
+  EVT FPTy = EVT::getFloatingPointVT(Op.getValueSizeInBits());
+  SDValue Trunc = DAG.getNode(MipsISD::TruncIntFP, Op.getDebugLoc(), FPTy,
+                              Op.getOperand(0));
+  return DAG.getNode(ISD::BITCAST, Op.getDebugLoc(), Op.getValueType(), Trunc);
+}
+
 //===----------------------------------------------------------------------===//
 //                      Calling Convention Implementation
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/Mips/MipsISelLowering.h b/lib/Target/Mips/MipsISelLowering.h
index 68f05ff80a..ff645e27e2 100644
--- a/lib/Target/Mips/MipsISelLowering.h
+++ b/lib/Target/Mips/MipsISelLowering.h
@@ -60,6 +60,9 @@ namespace llvm {
       CMovFP_T,
       CMovFP_F,
 
+      // FP-to-int truncation node.
+      TruncIntFP,
+
       // Return
       Ret,
 
@@ -361,6 +364,7 @@ namespace llvm {
     SDValue lowerLOAD(SDValue Op, SelectionDAG &DAG) const;
     SDValue lowerSTORE(SDValue Op, SelectionDAG &DAG) const;
     SDValue lowerADD(SDValue Op, SelectionDAG &DAG) const;
+    SDValue lowerFP_TO_SINT(SDValue Op, SelectionDAG &DAG) const;
 
     /// isEligibleForTailCallOptimization - Check whether the call is eligible
     /// for tail call optimization.
diff --git a/lib/Target/Mips/MipsInstrFPU.td b/lib/Target/Mips/MipsInstrFPU.td
index 6dc57e0709..e2acf284da 100644
--- a/lib/Target/Mips/MipsInstrFPU.td
+++ b/lib/Target/Mips/MipsInstrFPU.td
@@ -30,6 +30,7 @@ def SDT_MipsFPCmp : SDTypeProfile<0, 3, [SDTCisSameAs<0, 1>, SDTCisFP<1>,
                                          SDTCisVT<2, i32>]>;
 def SDT_MipsCMovFP : SDTypeProfile<1, 2, [SDTCisSameAs<0, 1>,
                                           SDTCisSameAs<1, 2>]>;
+def SDT_MipsTruncIntFP : SDTypeProfile<1, 1, [SDTCisFP<0>, SDTCisFP<1>]>;
 def SDT_MipsBuildPairF64 : SDTypeProfile<1, 2, [SDTCisVT<0, f64>,
                                                 SDTCisVT<1, i32>,
                                                 SDTCisSameAs<1, 2>]>;
@@ -42,6 +43,7 @@ def MipsCMovFP_T : SDNode<"MipsISD::CMovFP_T", SDT_MipsCMovFP, [SDNPInGlue]>;
 def MipsCMovFP_F : SDNode<"MipsISD::CMovFP_F", SDT_MipsCMovFP, [SDNPInGlue]>;
 def MipsFPBrcond : SDNode<"MipsISD::FPBrcond", SDT_MipsFPBrcond,
                           [SDNPHasChain, SDNPOptInGlue]>;
+def MipsTruncIntFP : SDNode<"MipsISD::TruncIntFP", SDT_MipsTruncIntFP>;
 def MipsBuildPairF64 : SDNode<"MipsISD::BuildPairF64", SDT_MipsBuildPairF64>;
 def MipsExtractElementF64 : SDNode<"MipsISD::ExtractElementF64",
                                    SDT_MipsExtractElementF64>;
@@ -485,13 +487,12 @@ def : MipsPat<(f32 fpimm0), (MTC1 ZERO)>;
 def : MipsPat<(f32 fpimm0neg), (FNEG_S (MTC1 ZERO))>;
 
 def : MipsPat<(f32 (sint_to_fp CPURegs:$src)), (PseudoCVT_S_W CPURegs:$src)>;
-def : MipsPat<(i32 (fp_to_sint FGR32:$src)), (MFC1 (TRUNC_W_S FGR32:$src))>;
+def : MipsPat<(MipsTruncIntFP FGR32:$src), (TRUNC_W_S FGR32:$src)>;
 
 let Predicates = [NotFP64bit, HasStdEnc] in {
   def : MipsPat<(f64 (sint_to_fp CPURegs:$src)),
                 (PseudoCVT_D32_W CPURegs:$src)>;
-  def : MipsPat<(i32 (fp_to_sint AFGR64:$src)),
-                (MFC1 (TRUNC_W_D32 AFGR64:$src))>;
+  def : MipsPat<(MipsTruncIntFP AFGR64:$src), (TRUNC_W_D32 AFGR64:$src)>;
   def : MipsPat<(f32 (fround AFGR64:$src)), (CVT_S_D32 AFGR64:$src)>;
   def : MipsPat<(f64 (fextend FGR32:$src)), (CVT_D32_S FGR32:$src)>;
 }
@@ -507,11 +508,9 @@ let Predicates = [IsFP64bit, HasStdEnc] in {
   def : MipsPat<(f64 (sint_to_fp CPU64Regs:$src)),
                 (PseudoCVT_D64_L CPU64Regs:$src)>;
 
-  def : MipsPat<(i32 (fp_to_sint FGR64:$src)),
-                (MFC1 (TRUNC_W_D64 FGR64:$src))>;
-  def : MipsPat<(i64 (fp_to_sint FGR32:$src)), (DMFC1 (TRUNC_L_S FGR32:$src))>;
-  def : MipsPat<(i64 (fp_to_sint FGR64:$src)),
-                (DMFC1 (TRUNC_L_D64 FGR64:$src))>;
+  def : MipsPat<(MipsTruncIntFP FGR64:$src), (TRUNC_W_D64 FGR64:$src)>;
+  def : MipsPat<(MipsTruncIntFP FGR32:$src), (TRUNC_L_S FGR32:$src)>;
+  def : MipsPat<(MipsTruncIntFP FGR64:$src), (TRUNC_L_D64 FGR64:$src)>;
 
   def : MipsPat<(f32 (fround FGR64:$src)), (CVT_S_D64 FGR64:$src)>;
   def : MipsPat<(f64 (fextend FGR32:$src)), (CVT_D64_S FGR32:$src)>;