DAG: Add helper for creating shifts with correct type

[arsenm]

ping

[efriedma]

I'm not really a fan of the LegalTypes boolean; it's just asking for people to pass the wrong value. Can we just check whether the type is legal, or something like that?

[bogner]

Patch LGTM.

In D49064#1183446, @efriedma wrote:

I'm not really a fan of the LegalTypes boolean; it's just asking for people to pass the wrong value. Can we just check whether the type is legal, or something like that?

I agree the LegalTypes boolean isn't ideal, but it isn't actually being introduced here (getShiftAmount already had it) so I don't see that conversation as blocking for this change.

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

571

Mark what the boolean argument is please (ie, /*LegalTypes=*/false or so)

[arsenm]

r354649

include/llvm/CodeGen/SelectionDAG.h

SDValue getAllOnesConstant(const SDLoc &DL, EVT VT, bool IsTarget = false,
     return getConstant(APInt::getAllOnesValue(VT.getScalarSizeInBits()), DL,
                        VT, IsTarget, IsOpaque);
   }
 
   SDValue getConstant(const ConstantInt &Val, const SDLoc &DL, EVT VT,
                       bool isTarget = false, bool isOpaque = false);
   SDValue getIntPtrConstant(uint64_t Val, const SDLoc &DL,
                             bool isTarget = false);
+  SDValue getShiftAmountConstant(uint64_t Val, EVT VT, const SDLoc &DL,
+                                 bool LegalTypes = true);
+
   SDValue getTargetConstant(uint64_t Val, const SDLoc &DL, EVT VT,
                             bool isOpaque = false) {
     return getConstant(Val, DL, VT, true, isOpaque);
   }
   SDValue getTargetConstant(const APInt &Val, const SDLoc &DL, EVT VT,
                             bool isOpaque = false) {
     return getConstant(Val, DL, VT, true, isOpaque);
   }

lib/CodeGen/SelectionDAG/SelectionDAG.cpp

SDValue SelectionDAG::getConstant(const ConstantInt &Val, const SDLoc &DL,
   return Result;
 }
 
 SDValue SelectionDAG::getIntPtrConstant(uint64_t Val, const SDLoc &DL,
                                         bool isTarget) {
   return getConstant(Val, DL, TLI->getPointerTy(getDataLayout()), isTarget);
 }
 
+SDValue SelectionDAG::getShiftAmountConstant(uint64_t Val, EVT VT,
+                                             const SDLoc &DL, bool LegalTypes) {
+  EVT ShiftVT = TLI->getShiftAmountTy(VT, getDataLayout(), LegalTypes);
+  return getConstant(Val, DL, ShiftVT);
+}
+
 SDValue SelectionDAG::getConstantFP(const APFloat &V, const SDLoc &DL, EVT VT,
                                     bool isTarget) {
   return getConstantFP(*ConstantFP::get(*getContext(), V), DL, VT, isTarget);
 }
 
 SDValue SelectionDAG::getConstantFP(const ConstantFP &V, const SDLoc &DL,
                                     EVT VT, bool isTarget) {
   assert(VT.isFloatingPoint() && "Cannot create integer FP constant!");

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

static void getCopyToParts(SelectionDAG &DAG, const SDLoc &DL, SDValue Val,
   if (NumParts & (NumParts - 1)) {
     // The number of parts is not a power of 2.  Split off and copy the tail.
     assert(PartVT.isInteger() && ValueVT.isInteger() &&
            "Do not know what to expand to!");
     unsigned RoundParts = 1 << Log2_32(NumParts);
     unsigned RoundBits = RoundParts * PartBits;
     unsigned OddParts = NumParts - RoundParts;
     SDValue OddVal = DAG.getNode(ISD::SRL, DL, ValueVT, Val,
-                                 DAG.getIntPtrConstant(RoundBits, DL));
+      DAG.getShiftAmountConstant(RoundBits, ValueVT, DL, false));
+
     getCopyToParts(DAG, DL, OddVal, Parts + RoundParts, OddParts, PartVT, V,
                    CallConv);
 
     if (DAG.getDataLayout().isBigEndian())
       // The odd parts were reversed by getCopyToParts - unreverse them.
       std::reverse(Parts + RoundParts, Parts + NumParts);
 
     NumParts = RoundParts;