[NVPTX] Move getDivF32Level, usePrecSqrtF32, and useF32FTZ into out of DAGToDAG and into TargetLowering.

[jlebar]

Summary

DADToDAG has access to TargetLowering, but not vice versa, so this is
the more general location for these functions.

NFC

[tra]

llvm/lib/Target/NVPTX/NVPTXISelLowering.h

513

This looks like a todo item. :-)

[jlebar]

Add missing comments. Oops. :)

llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp

 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetIntrinsicInfo.h"
 
 using namespace llvm;
 
 #define DEBUG_TYPE "nvptx-isel"
 
-static cl::opt<int> UsePrecDivF32(
-    "nvptx-prec-divf32", cl::ZeroOrMore, cl::Hidden,
-    cl::desc("NVPTX Specifies: 0 use div.approx, 1 use div.full, 2 use"
-             " IEEE Compliant F32 div.rnd if available."),
-    cl::init(2));
-
-static cl::opt<bool>
-UsePrecSqrtF32("nvptx-prec-sqrtf32", cl::Hidden,
-          cl::desc("NVPTX Specific: 0 use sqrt.approx, 1 use sqrt.rn."),
-          cl::init(true));
-
-static cl::opt<bool>
-FtzEnabled("nvptx-f32ftz", cl::ZeroOrMore, cl::Hidden,
-           cl::desc("NVPTX Specific: Flush f32 subnormals to sign-preserving zero."),
-           cl::init(false));
-
 /// createNVPTXISelDag - This pass converts a legalized DAG into a
 /// NVPTX-specific DAG, ready for instruction scheduling.
 FunctionPass *llvm::createNVPTXISelDag(NVPTXTargetMachine &TM,
                                        llvm::CodeGenOpt::Level OptLevel) {
   return new NVPTXDAGToDAGISel(TM, OptLevel);
 }
 
 NVPTXDAGToDAGISel::NVPTXDAGToDAGISel(NVPTXTargetMachine &tm,
                                      CodeGenOpt::Level OptLevel)
     : SelectionDAGISel(tm, OptLevel), TM(tm) {
   doMulWide = (OptLevel > 0);
 }
 
 bool NVPTXDAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
-    Subtarget = &static_cast<const NVPTXSubtarget &>(MF.getSubtarget());
-    return SelectionDAGISel::runOnMachineFunction(MF);
 }
 
 int NVPTXDAGToDAGISel::getDivF32Level() const {
-  if (UsePrecDivF32.getNumOccurrences() > 0) {
-    // If nvptx-prec-div32=N is used on the command-line, always honor it
-    return UsePrecDivF32;
-  } else {
-    // Otherwise, use div.approx if fast math is enabled
-    if (TM.Options.UnsafeFPMath)
-      return 0;
-    else
-      return 2;
-  }
+  return Subtarget->getTargetLowering()->getDivF32Level();
 }
 
 bool NVPTXDAGToDAGISel::usePrecSqrtF32() const {
-  if (UsePrecSqrtF32.getNumOccurrences() > 0) {
-    // If nvptx-prec-sqrtf32 is used on the command-line, always honor it
-    return UsePrecSqrtF32;
-  } else {
-    // Otherwise, use sqrt.approx if fast math is enabled
-    return !TM.Options.UnsafeFPMath;
-  }
+  return Subtarget->getTargetLowering()->usePrecSqrtF32();
 }
 
 bool NVPTXDAGToDAGISel::useF32FTZ() const {
-  if (FtzEnabled.getNumOccurrences() > 0) {
-    // If nvptx-f32ftz is used on the command-line, always honor it
-    return FtzEnabled;
-  } else {
-    const Function *F = MF->getFunction();
-    // Otherwise, check for an nvptx-f32ftz attribute on the function
-    if (F->hasFnAttribute("nvptx-f32ftz"))
-      return F->getFnAttribute("nvptx-f32ftz").getValueAsString() == "true";
-    else
-      return false;
-  }
+  return Subtarget->getTargetLowering()->useF32FTZ(*MF);
 }
 
 bool NVPTXDAGToDAGISel::allowFMA() const {
   const NVPTXTargetLowering *TL = Subtarget->getTargetLowering();
   return TL->allowFMA(*MF, OptLevel);
 }
 
 bool NVPTXDAGToDAGISel::allowUnsafeFPMath() const {

llvm/lib/Target/NVPTX/NVPTXISelLowering.h

public:
   // PTX always uses 32-bit shift amounts
   MVT getScalarShiftAmountTy(const DataLayout &, EVT) const override {
     return MVT::i32;
   }
 
   TargetLoweringBase::LegalizeTypeAction
   getPreferredVectorAction(EVT VT) const override;
 
+  // XXX comments
+  int getDivF32Level() const;
+  bool usePrecSqrtF32() const;
+  bool useF32FTZ(const MachineFunction &MF) const;
+
   bool allowFMA(MachineFunction &MF, CodeGenOpt::Level OptLevel) const;
   bool allowUnsafeFPMath(MachineFunction &MF) const;
 
   bool isFMAFasterThanFMulAndFAdd(EVT) const override { return true; }
 
   bool enableAggressiveFMAFusion(EVT VT) const override { return true; }
 
   // The default is to transform llvm.ctlz(x, false) (where false indicates that

llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp

static cl::opt<bool> sched4reg(
     cl::desc("NVPTX Specific: schedule for register pressue"), cl::init(false));
 
 static cl::opt<unsigned>
 FMAContractLevelOpt("nvptx-fma-level", cl::ZeroOrMore, cl::Hidden,
                     cl::desc("NVPTX Specific: FMA contraction (0: don't do it"
                              " 1: do it  2: do it aggressively"),
                     cl::init(2));
 
+static cl::opt<int> UsePrecDivF32(
+    "nvptx-prec-divf32", cl::ZeroOrMore, cl::Hidden,
+    cl::desc("NVPTX Specifies: 0 use div.approx, 1 use div.full, 2 use"
+             " IEEE Compliant F32 div.rnd if available."),
+    cl::init(2));
+
+static cl::opt<bool> UsePrecSqrtF32(
+    "nvptx-prec-sqrtf32", cl::Hidden,
+    cl::desc("NVPTX Specific: 0 use sqrt.approx, 1 use sqrt.rn."),
+    cl::init(true));
+
+static cl::opt<bool> FtzEnabled(
+    "nvptx-f32ftz", cl::ZeroOrMore, cl::Hidden,
+    cl::desc("NVPTX Specific: Flush f32 subnormals to sign-preserving zero."),
+    cl::init(false));
+
+int NVPTXTargetLowering::getDivF32Level() const {
+  if (UsePrecDivF32.getNumOccurrences() > 0) {
+    // If nvptx-prec-div32=N is used on the command-line, always honor it
+    return UsePrecDivF32;
+  } else {
+    // Otherwise, use div.approx if fast math is enabled
+    if (getTargetMachine().Options.UnsafeFPMath)
+      return 0;
+    else
+      return 2;
+  }
+}
+
+bool NVPTXTargetLowering::usePrecSqrtF32() const {
+  if (UsePrecSqrtF32.getNumOccurrences() > 0) {
+    // If nvptx-prec-sqrtf32 is used on the command-line, always honor it
+    return UsePrecSqrtF32;
+  } else {
+    // Otherwise, use sqrt.approx if fast math is enabled
+    return !getTargetMachine().Options.UnsafeFPMath;
+  }
+}
+
+bool NVPTXTargetLowering::useF32FTZ(const MachineFunction &MF) const {
+  // TODO: Get rid of this flag; there can be only one way to do this.
+  if (FtzEnabled.getNumOccurrences() > 0) {
+    // If nvptx-f32ftz is used on the command-line, always honor it
+    return FtzEnabled;
+  } else {
+    const Function *F = MF.getFunction();
+    // Otherwise, check for an nvptx-f32ftz attribute on the function
+    if (F->hasFnAttribute("nvptx-f32ftz"))
+      return F->getFnAttribute("nvptx-f32ftz").getValueAsString() == "true";
+    else
+      return false;
+  }
+}
+
 static bool IsPTXVectorType(MVT VT) {
   switch (VT.SimpleTy) {
   default:
     return false;
   case MVT::v2i1:
   case MVT::v4i1:
   case MVT::v2i8:
   case MVT::v4i8: