[AMDGPU] Remove widen-16-bit-ops from CGP (#145483)

This was already off by default so there is no codegen change.

Author: Pierre-vh

llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp

@@ -45,12 +45,6 @@ static cl::opt<bool> WidenLoads(
   cl::ReallyHidden,
   cl::init(false));
 
-static cl::opt<bool> Widen16BitOps(
-    "amdgpu-codegenprepare-widen-16-bit-ops",
-    cl::desc(
-        "Widen uniform 16-bit instructions to 32-bit in AMDGPUCodeGenPrepare"),
-    cl::ReallyHidden, cl::init(false));
-
 static cl::opt<bool>
     BreakLargePHIs("amdgpu-codegenprepare-break-large-phis",
                    cl::desc("Break large PHI nodes for DAGISel"),
@@ -150,18 +144,6 @@ class AMDGPUCodeGenPrepareImpl
 
   bool canBreakPHINode(const PHINode &I);
 
-  /// Copies exact/nsw/nuw flags (if any) from binary operation \p I to
-  /// binary operation \p V.
-  ///
-  /// \returns Binary operation \p V.
-  /// \returns \p T's base element bit width.
-  unsigned getBaseElementBitWidth(const Type *T) const;
-
-  /// \returns Equivalent 32 bit integer type for given type \p T. For example,
-  /// if \p T is i7, then i32 is returned; if \p T is <3 x i12>, then <3 x i32>
-  /// is returned.
-  Type *getI32Ty(IRBuilder<> &B, const Type *T) const;
-
   /// \returns True if binary operation \p I is a signed binary operation, false
   /// otherwise.
   bool isSigned(const BinaryOperator &I) const;
@@ -170,10 +152,6 @@ class AMDGPUCodeGenPrepareImpl
   /// signed 'icmp' operation, false otherwise.
   bool isSigned(const SelectInst &I) const;
 
-  /// \returns True if type \p T needs to be promoted to 32 bit integer type,
-  /// false otherwise.
-  bool needsPromotionToI32(const Type *T) const;
-
   /// Return true if \p T is a legal scalar floating point type.
   bool isLegalFloatingTy(const Type *T) const;
 
@@ -188,52 +166,6 @@ class AMDGPUCodeGenPrepareImpl
            computeKnownFPClass(V, fcSubnormal, CtxI).isKnownNeverSubnormal();
   }
 
-  /// Promotes uniform binary operation \p I to equivalent 32 bit binary
-  /// operation.
-  ///
-  /// \details \p I's base element bit width must be greater than 1 and less
-  /// than or equal 16. Promotion is done by sign or zero extending operands to
-  /// 32 bits, replacing \p I with equivalent 32 bit binary operation, and
-  /// truncating the result of 32 bit binary operation back to \p I's original
-  /// type. Division operation is not promoted.
-  ///
-  /// \returns True if \p I is promoted to equivalent 32 bit binary operation,
-  /// false otherwise.
-  bool promoteUniformOpToI32(BinaryOperator &I) const;
-
-  /// Promotes uniform 'icmp' operation \p I to 32 bit 'icmp' operation.
-  ///
-  /// \details \p I's base element bit width must be greater than 1 and less
-  /// than or equal 16. Promotion is done by sign or zero extending operands to
-  /// 32 bits, and replacing \p I with 32 bit 'icmp' operation.
-  ///
-  /// \returns True.
-  bool promoteUniformOpToI32(ICmpInst &I) const;
-
-  /// Promotes uniform 'select' operation \p I to 32 bit 'select'
-  /// operation.
-  ///
-  /// \details \p I's base element bit width must be greater than 1 and less
-  /// than or equal 16. Promotion is done by sign or zero extending operands to
-  /// 32 bits, replacing \p I with 32 bit 'select' operation, and truncating the
-  /// result of 32 bit 'select' operation back to \p I's original type.
-  ///
-  /// \returns True.
-  bool promoteUniformOpToI32(SelectInst &I) const;
-
-  /// Promotes uniform 'bitreverse' intrinsic \p I to 32 bit 'bitreverse'
-  /// intrinsic.
-  ///
-  /// \details \p I's base element bit width must be greater than 1 and less
-  /// than or equal 16. Promotion is done by zero extending the operand to 32
-  /// bits, replacing \p I with 32 bit 'bitreverse' intrinsic, shifting the
-  /// result of 32 bit 'bitreverse' intrinsic to the right with zero fill (the
-  /// shift amount is 32 minus \p I's base element bit width), and truncating
-  /// the result of the shift operation back to \p I's original type.
-  ///
-  /// \returns True.
-  bool promoteUniformBitreverseToI32(IntrinsicInst &I) const;
-
   /// \returns The minimum number of bits needed to store the value of \Op as an
   /// unsigned integer. Truncating to this size and then zero-extending to
   /// the original will not change the value.
@@ -320,13 +252,11 @@ class AMDGPUCodeGenPrepareImpl
   bool visitInstruction(Instruction &I) { return false; }
   bool visitBinaryOperator(BinaryOperator &I);
   bool visitLoadInst(LoadInst &I);
-  bool visitICmpInst(ICmpInst &I);
   bool visitSelectInst(SelectInst &I);
   bool visitPHINode(PHINode &I);
   bool visitAddrSpaceCastInst(AddrSpaceCastInst &I);
 
   bool visitIntrinsicInst(IntrinsicInst &I);
-  bool visitBitreverseIntrinsicInst(IntrinsicInst &I);
   bool visitFMinLike(IntrinsicInst &I);
   bool visitSqrt(IntrinsicInst &I);
   bool run();
@@ -380,22 +310,6 @@ bool AMDGPUCodeGenPrepareImpl::run() {
   return MadeChange;
 }
 
-unsigned AMDGPUCodeGenPrepareImpl::getBaseElementBitWidth(const Type *T) const {
-  assert(needsPromotionToI32(T) && "T does not need promotion to i32");
-
-  if (T->isIntegerTy())
-    return T->getIntegerBitWidth();
-  return cast<VectorType>(T)->getElementType()->getIntegerBitWidth();
-}
-
-Type *AMDGPUCodeGenPrepareImpl::getI32Ty(IRBuilder<> &B, const Type *T) const {
-  assert(needsPromotionToI32(T) && "T does not need promotion to i32");
-
-  if (T->isIntegerTy())
-    return B.getInt32Ty();
-  return FixedVectorType::get(B.getInt32Ty(), cast<FixedVectorType>(T));
-}
-
 bool AMDGPUCodeGenPrepareImpl::isSigned(const BinaryOperator &I) const {
   return I.getOpcode() == Instruction::AShr ||
       I.getOpcode() == Instruction::SDiv || I.getOpcode() == Instruction::SRem;
@@ -406,59 +320,11 @@ bool AMDGPUCodeGenPrepareImpl::isSigned(const SelectInst &I) const {
          cast<ICmpInst>(I.getOperand(0))->isSigned();
 }
 
-bool AMDGPUCodeGenPrepareImpl::needsPromotionToI32(const Type *T) const {
-  if (!Widen16BitOps)
-    return false;
-
-  const IntegerType *IntTy = dyn_cast<IntegerType>(T);
-  if (IntTy && IntTy->getBitWidth() > 1 && IntTy->getBitWidth() <= 16)
-    return true;
-
-  if (const VectorType *VT = dyn_cast<VectorType>(T)) {
-    // TODO: The set of packed operations is more limited, so may want to
-    // promote some anyway.
-    if (ST.hasVOP3PInsts())
-      return false;
-
-    return needsPromotionToI32(VT->getElementType());
-  }
-
-  return false;
-}
-
 bool AMDGPUCodeGenPrepareImpl::isLegalFloatingTy(const Type *Ty) const {
   return Ty->isFloatTy() || Ty->isDoubleTy() ||
          (Ty->isHalfTy() && ST.has16BitInsts());
 }
 
-// Return true if the op promoted to i32 should have nsw set.
-static bool promotedOpIsNSW(const Instruction &I) {
-  switch (I.getOpcode()) {
-  case Instruction::Shl:
-  case Instruction::Add:
-  case Instruction::Sub:
-    return true;
-  case Instruction::Mul:
-    return I.hasNoUnsignedWrap();
-  default:
-    return false;
-  }
-}
-
-// Return true if the op promoted to i32 should have nuw set.
-static bool promotedOpIsNUW(const Instruction &I) {
-  switch (I.getOpcode()) {
-  case Instruction::Shl:
-  case Instruction::Add:
-  case Instruction::Mul:
-    return true;
-  case Instruction::Sub:
-    return I.hasNoUnsignedWrap();
-  default:
-    return false;
-  }
-}
-
 bool AMDGPUCodeGenPrepareImpl::canWidenScalarExtLoad(LoadInst &I) const {
   Type *Ty = I.getType();
   int TySize = DL.getTypeSizeInBits(Ty);
@@ -467,134 +333,6 @@ bool AMDGPUCodeGenPrepareImpl::canWidenScalarExtLoad(LoadInst &I) const {
   return I.isSimple() && TySize < 32 && Alignment >= 4 && UA.isUniform(&I);
 }
 
-bool AMDGPUCodeGenPrepareImpl::promoteUniformOpToI32(BinaryOperator &I) const {
-  assert(needsPromotionToI32(I.getType()) &&
-         "I does not need promotion to i32");
-
-  if (I.getOpcode() == Instruction::SDiv ||
-      I.getOpcode() == Instruction::UDiv ||
-      I.getOpcode() == Instruction::SRem ||
-      I.getOpcode() == Instruction::URem)
-    return false;
-
-  IRBuilder<> Builder(&I);
-  Builder.SetCurrentDebugLocation(I.getDebugLoc());
-
-  Type *I32Ty = getI32Ty(Builder, I.getType());
-  Value *ExtOp0 = nullptr;
-  Value *ExtOp1 = nullptr;
-  Value *ExtRes = nullptr;
-  Value *TruncRes = nullptr;
-
-  if (isSigned(I)) {
-    ExtOp0 = Builder.CreateSExt(I.getOperand(0), I32Ty);
-    ExtOp1 = Builder.CreateSExt(I.getOperand(1), I32Ty);
-  } else {
-    ExtOp0 = Builder.CreateZExt(I.getOperand(0), I32Ty);
-    ExtOp1 = Builder.CreateZExt(I.getOperand(1), I32Ty);
-  }
-
-  ExtRes = Builder.CreateBinOp(I.getOpcode(), ExtOp0, ExtOp1);
-  if (Instruction *Inst = dyn_cast<Instruction>(ExtRes)) {
-    if (promotedOpIsNSW(cast<Instruction>(I)))
-      Inst->setHasNoSignedWrap();
-
-    if (promotedOpIsNUW(cast<Instruction>(I)))
-      Inst->setHasNoUnsignedWrap();
-
-    if (const auto *ExactOp = dyn_cast<PossiblyExactOperator>(&I))
-      Inst->setIsExact(ExactOp->isExact());
-  }
-
-  TruncRes = Builder.CreateTrunc(ExtRes, I.getType());
-
-  I.replaceAllUsesWith(TruncRes);
-  I.eraseFromParent();
-
-  return true;
-}
-
-bool AMDGPUCodeGenPrepareImpl::promoteUniformOpToI32(ICmpInst &I) const {
-  assert(needsPromotionToI32(I.getOperand(0)->getType()) &&
-         "I does not need promotion to i32");
-
-  IRBuilder<> Builder(&I);
-  Builder.SetCurrentDebugLocation(I.getDebugLoc());
-
-  Type *I32Ty = getI32Ty(Builder, I.getOperand(0)->getType());
-  Value *ExtOp0 = nullptr;
-  Value *ExtOp1 = nullptr;
-  Value *NewICmp  = nullptr;
-
-  if (I.isSigned()) {
-    ExtOp0 = Builder.CreateSExt(I.getOperand(0), I32Ty);
-    ExtOp1 = Builder.CreateSExt(I.getOperand(1), I32Ty);
-  } else {
-    ExtOp0 = Builder.CreateZExt(I.getOperand(0), I32Ty);
-    ExtOp1 = Builder.CreateZExt(I.getOperand(1), I32Ty);
-  }
-  NewICmp = Builder.CreateICmp(I.getPredicate(), ExtOp0, ExtOp1);
-
-  I.replaceAllUsesWith(NewICmp);
-  I.eraseFromParent();
-
-  return true;
-}
-
-bool AMDGPUCodeGenPrepareImpl::promoteUniformOpToI32(SelectInst &I) const {
-  assert(needsPromotionToI32(I.getType()) &&
-         "I does not need promotion to i32");
-
-  IRBuilder<> Builder(&I);
-  Builder.SetCurrentDebugLocation(I.getDebugLoc());
-
-  Type *I32Ty = getI32Ty(Builder, I.getType());
-  Value *ExtOp1 = nullptr;
-  Value *ExtOp2 = nullptr;
-  Value *ExtRes = nullptr;
-  Value *TruncRes = nullptr;
-
-  if (isSigned(I)) {
-    ExtOp1 = Builder.CreateSExt(I.getOperand(1), I32Ty);
-    ExtOp2 = Builder.CreateSExt(I.getOperand(2), I32Ty);
-  } else {
-    ExtOp1 = Builder.CreateZExt(I.getOperand(1), I32Ty);
-    ExtOp2 = Builder.CreateZExt(I.getOperand(2), I32Ty);
-  }
-  ExtRes = Builder.CreateSelect(I.getOperand(0), ExtOp1, ExtOp2);
-  TruncRes = Builder.CreateTrunc(ExtRes, I.getType());
-
-  I.replaceAllUsesWith(TruncRes);
-  I.eraseFromParent();
-
-  return true;
-}
-
-bool AMDGPUCodeGenPrepareImpl::promoteUniformBitreverseToI32(
-    IntrinsicInst &I) const {
-  assert(I.getIntrinsicID() == Intrinsic::bitreverse &&
-         "I must be bitreverse intrinsic");
-  assert(needsPromotionToI32(I.getType()) &&
-         "I does not need promotion to i32");
-
-  IRBuilder<> Builder(&I);
-  Builder.SetCurrentDebugLocation(I.getDebugLoc());
-
-  Type *I32Ty = getI32Ty(Builder, I.getType());
-  Value *ExtOp = Builder.CreateZExt(I.getOperand(0), I32Ty);
-  Value *ExtRes =
-      Builder.CreateIntrinsic(Intrinsic::bitreverse, {I32Ty}, {ExtOp});
-  Value *LShrOp =
-      Builder.CreateLShr(ExtRes, 32 - getBaseElementBitWidth(I.getType()));
-  Value *TruncRes =
-      Builder.CreateTrunc(LShrOp, I.getType());
-
-  I.replaceAllUsesWith(TruncRes);
-  I.eraseFromParent();
-
-  return true;
-}
-
 unsigned AMDGPUCodeGenPrepareImpl::numBitsUnsigned(Value *Op) const {
   return computeKnownBits(Op, DL, AC).countMaxActiveBits();
 }
@@ -1635,10 +1373,6 @@ bool AMDGPUCodeGenPrepareImpl::visitBinaryOperator(BinaryOperator &I) {
   if (foldBinOpIntoSelect(I))
     return true;
 
-  if (ST.has16BitInsts() && needsPromotionToI32(I.getType()) &&
-      UA.isUniform(&I) && promoteUniformOpToI32(I))
-    return true;
-
   if (UseMul24Intrin && replaceMulWithMul24(I))
     return true;
   if (tryNarrowMathIfNoOverflow(&I, ST.getTargetLowering(),
@@ -1770,29 +1504,13 @@ bool AMDGPUCodeGenPrepareImpl::visitLoadInst(LoadInst &I) {
   return false;
 }
 
-bool AMDGPUCodeGenPrepareImpl::visitICmpInst(ICmpInst &I) {
-  bool Changed = false;
-
-  if (ST.has16BitInsts() && needsPromotionToI32(I.getOperand(0)->getType()) &&
-      UA.isUniform(&I))
-    Changed |= promoteUniformOpToI32(I);
-
-  return Changed;
-}
-
 bool AMDGPUCodeGenPrepareImpl::visitSelectInst(SelectInst &I) {
   Value *Cond = I.getCondition();
   Value *TrueVal = I.getTrueValue();
   Value *FalseVal = I.getFalseValue();
   Value *CmpVal;
   CmpPredicate Pred;
 
-  if (ST.has16BitInsts() && needsPromotionToI32(I.getType())) {
-    if (UA.isUniform(&I))
-      return promoteUniformOpToI32(I);
-    return false;
-  }
-
   // Match fract pattern with nan check.
   if (!match(Cond, m_FCmp(Pred, m_Value(CmpVal), m_NonNaN())))
     return false;
@@ -2196,8 +1914,6 @@ bool AMDGPUCodeGenPrepareImpl::visitAddrSpaceCastInst(AddrSpaceCastInst &I) {
 
 bool AMDGPUCodeGenPrepareImpl::visitIntrinsicInst(IntrinsicInst &I) {
   switch (I.getIntrinsicID()) {
-  case Intrinsic::bitreverse:
-    return visitBitreverseIntrinsicInst(I);
   case Intrinsic::minnum:
   case Intrinsic::minimumnum:
   case Intrinsic::minimum:
@@ -2209,16 +1925,6 @@ bool AMDGPUCodeGenPrepareImpl::visitIntrinsicInst(IntrinsicInst &I) {
   }
 }
 
-bool AMDGPUCodeGenPrepareImpl::visitBitreverseIntrinsicInst(IntrinsicInst &I) {
-  bool Changed = false;
-
-  if (ST.has16BitInsts() && needsPromotionToI32(I.getType()) &&
-      UA.isUniform(&I))
-    Changed |= promoteUniformBitreverseToI32(I);
-
-  return Changed;
-}
-
 /// Match non-nan fract pattern.
 ///   minnum(fsub(x, floor(x)), nextafter(1.0, -1.0))
 ///   minimumnum(fsub(x, floor(x)), nextafter(1.0, -1.0))