vendor/clang/clang-trunk-r366426

1 files changed, 304 insertions, 163 deletions

diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index 1c14d4c99a23..3d082de2a14f 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -1,9 +1,8 @@
 //===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
@@ -17,6 +16,7 @@
 #include "CGObjCRuntime.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
+#include "ConstantEmitter.h"
 #include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclObjC.h"
@@ -125,6 +125,21 @@ struct BinOpInfo {
         return CFP->isZero();
     return true;
   }
+
+  /// Check if either operand is a fixed point type or integer type, with at
+  /// least one being a fixed point type. In any case, this
+  /// operation did not follow usual arithmetic conversion and both operands may
+  /// not be the same.
+  bool isFixedPointBinOp() const {
+    // We cannot simply check the result type since comparison operations return
+    // an int.
+    if (const auto *BinOp = dyn_cast<BinaryOperator>(E)) {
+      QualType LHSType = BinOp->getLHS()->getType();
+      QualType RHSType = BinOp->getRHS()->getType();
+      return LHSType->isFixedPointType() || RHSType->isFixedPointType();
+    }
+    return false;
+  }
 };
 
 static bool MustVisitNullValue(const Expr *E) {
@@ -298,7 +313,7 @@ public:
   /// boolean (i1) truth value.  This is equivalent to "Val != 0".
   Value *EmitConversionToBool(Value *Src, QualType DstTy);
 
-  /// Emit a check that a conversion to or from a floating-point type does not
+  /// Emit a check that a conversion from a floating-point type does not
   /// overflow.
   void EmitFloatConversionCheck(Value *OrigSrc, QualType OrigSrcType,
                                 Value *Src, QualType SrcType, QualType DstType,
@@ -349,8 +364,14 @@ public:
                        SourceLocation Loc,
                        ScalarConversionOpts Opts = ScalarConversionOpts());
 
+  /// Convert between either a fixed point and other fixed point or fixed point
+  /// and an integer.
   Value *EmitFixedPointConversion(Value *Src, QualType SrcTy, QualType DstTy,
                                   SourceLocation Loc);
+  Value *EmitFixedPointConversion(Value *Src, FixedPointSemantics &SrcFixedSema,
+                                  FixedPointSemantics &DstFixedSema,
+                                  SourceLocation Loc,
+                                  bool DstIsInteger = false);
 
   /// Emit a conversion from the specified complex type to the specified
   /// destination type, where the destination type is an LLVM scalar type.
@@ -620,12 +641,20 @@ public:
   Value *VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E) {
     return EmitLoadOfLValue(E);
   }
+  Value *VisitSourceLocExpr(SourceLocExpr *SLE) {
+    auto &Ctx = CGF.getContext();
+    APValue Evaluated =
+        SLE->EvaluateInContext(Ctx, CGF.CurSourceLocExprScope.getDefaultExpr());
+    return ConstantEmitter(CGF.CGM, &CGF)
+        .emitAbstract(SLE->getLocation(), Evaluated, SLE->getType());
+  }
 
   Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
+    CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE);
     return Visit(DAE->getExpr());
   }
   Value *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) {
-    CodeGenFunction::CXXDefaultInitExprScope Scope(CGF);
+    CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE);
     return Visit(DIE->getExpr());
   }
   Value *VisitCXXThisExpr(CXXThisExpr *TE) {
@@ -729,6 +758,9 @@ public:
     return Builder.CreateOr(Ops.LHS, Ops.RHS, "or");
   }
 
+  // Helper functions for fixed point binary operations.
+  Value *EmitFixedPointBinOp(const BinOpInfo &Ops);
+
   BinOpInfo EmitBinOps(const BinaryOperator *E);
   LValue EmitCompoundAssignLValue(const CompoundAssignOperator *E,
                             Value *(ScalarExprEmitter::*F)(const BinOpInfo &),
@@ -832,128 +864,63 @@ Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) {
 void ScalarExprEmitter::EmitFloatConversionCheck(
     Value *OrigSrc, QualType OrigSrcType, Value *Src, QualType SrcType,
     QualType DstType, llvm::Type *DstTy, SourceLocation Loc) {
+  assert(SrcType->isFloatingType() && "not a conversion from floating point");
+  if (!isa<llvm::IntegerType>(DstTy))
+    return;
+
   CodeGenFunction::SanitizerScope SanScope(&CGF);
   using llvm::APFloat;
   using llvm::APSInt;
 
-  llvm::Type *SrcTy = Src->getType();
-
   llvm::Value *Check = nullptr;
-  if (llvm::IntegerType *IntTy = dyn_cast<llvm::IntegerType>(SrcTy)) {
-    // Integer to floating-point. This can fail for unsigned short -> __half
-    // or unsigned __int128 -> float.
-    assert(DstType->isFloatingType());
-    bool SrcIsUnsigned = OrigSrcType->isUnsignedIntegerOrEnumerationType();
-
-    APFloat LargestFloat =
-      APFloat::getLargest(CGF.getContext().getFloatTypeSemantics(DstType));
-    APSInt LargestInt(IntTy->getBitWidth(), SrcIsUnsigned);
-
-    bool IsExact;
-    if (LargestFloat.convertToInteger(LargestInt, APFloat::rmTowardZero,
-                                      &IsExact) != APFloat::opOK)
-      // The range of representable values of this floating point type includes
-      // all values of this integer type. Don't need an overflow check.
-      return;
-
-    llvm::Value *Max = llvm::ConstantInt::get(VMContext, LargestInt);
-    if (SrcIsUnsigned)
-      Check = Builder.CreateICmpULE(Src, Max);
-    else {
-      llvm::Value *Min = llvm::ConstantInt::get(VMContext, -LargestInt);
-      llvm::Value *GE = Builder.CreateICmpSGE(Src, Min);
-      llvm::Value *LE = Builder.CreateICmpSLE(Src, Max);
-      Check = Builder.CreateAnd(GE, LE);
-    }
-  } else {
-    const llvm::fltSemantics &SrcSema =
-      CGF.getContext().getFloatTypeSemantics(OrigSrcType);
-    if (isa<llvm::IntegerType>(DstTy)) {
-      // Floating-point to integer. This has undefined behavior if the source is
-      // +-Inf, NaN, or doesn't fit into the destination type (after truncation
-      // to an integer).
-      unsigned Width = CGF.getContext().getIntWidth(DstType);
-      bool Unsigned = DstType->isUnsignedIntegerOrEnumerationType();
-
-      APSInt Min = APSInt::getMinValue(Width, Unsigned);
-      APFloat MinSrc(SrcSema, APFloat::uninitialized);
-      if (MinSrc.convertFromAPInt(Min, !Unsigned, APFloat::rmTowardZero) &
-          APFloat::opOverflow)
-        // Don't need an overflow check for lower bound. Just check for
-        // -Inf/NaN.
-        MinSrc = APFloat::getInf(SrcSema, true);
-      else
-        // Find the largest value which is too small to represent (before
-        // truncation toward zero).
-        MinSrc.subtract(APFloat(SrcSema, 1), APFloat::rmTowardNegative);
-
-      APSInt Max = APSInt::getMaxValue(Width, Unsigned);
-      APFloat MaxSrc(SrcSema, APFloat::uninitialized);
-      if (MaxSrc.convertFromAPInt(Max, !Unsigned, APFloat::rmTowardZero) &
-          APFloat::opOverflow)
-        // Don't need an overflow check for upper bound. Just check for
-        // +Inf/NaN.
-        MaxSrc = APFloat::getInf(SrcSema, false);
-      else
-        // Find the smallest value which is too large to represent (before
-        // truncation toward zero).
-        MaxSrc.add(APFloat(SrcSema, 1), APFloat::rmTowardPositive);
-
-      // If we're converting from __half, convert the range to float to match
-      // the type of src.
-      if (OrigSrcType->isHalfType()) {
-        const llvm::fltSemantics &Sema =
-          CGF.getContext().getFloatTypeSemantics(SrcType);
-        bool IsInexact;
-        MinSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact);
-        MaxSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact);
-      }
-
-      llvm::Value *GE =
-        Builder.CreateFCmpOGT(Src, llvm::ConstantFP::get(VMContext, MinSrc));
-      llvm::Value *LE =
-        Builder.CreateFCmpOLT(Src, llvm::ConstantFP::get(VMContext, MaxSrc));
-      Check = Builder.CreateAnd(GE, LE);
-    } else {
-      // FIXME: Maybe split this sanitizer out from float-cast-overflow.
-      //
-      // Floating-point to floating-point. This has undefined behavior if the
-      // source is not in the range of representable values of the destination
-      // type. The C and C++ standards are spectacularly unclear here. We
-      // diagnose finite out-of-range conversions, but allow infinities and NaNs
-      // to convert to the corresponding value in the smaller type.
-      //
-      // C11 Annex F gives all such conversions defined behavior for IEC 60559
-      // conforming implementations. Unfortunately, LLVM's fptrunc instruction
-      // does not.
-
-      // Converting from a lower rank to a higher rank can never have
-      // undefined behavior, since higher-rank types must have a superset
-      // of values of lower-rank types.
-      if (CGF.getContext().getFloatingTypeOrder(OrigSrcType, DstType) != 1)
-        return;
-
-      assert(!OrigSrcType->isHalfType() &&
-             "should not check conversion from __half, it has the lowest rank");
-
-      const llvm::fltSemantics &DstSema =
-        CGF.getContext().getFloatTypeSemantics(DstType);
-      APFloat MinBad = APFloat::getLargest(DstSema, false);
-      APFloat MaxBad = APFloat::getInf(DstSema, false);
-
-      bool IsInexact;
-      MinBad.convert(SrcSema, APFloat::rmTowardZero, &IsInexact);
-      MaxBad.convert(SrcSema, APFloat::rmTowardZero, &IsInexact);
-
-      Value *AbsSrc = CGF.EmitNounwindRuntimeCall(
-        CGF.CGM.getIntrinsic(llvm::Intrinsic::fabs, Src->getType()), Src);
-      llvm::Value *GE =
-        Builder.CreateFCmpOGT(AbsSrc, llvm::ConstantFP::get(VMContext, MinBad));
-      llvm::Value *LE =
-        Builder.CreateFCmpOLT(AbsSrc, llvm::ConstantFP::get(VMContext, MaxBad));
-      Check = Builder.CreateNot(Builder.CreateAnd(GE, LE));
-    }
-  }
+  const llvm::fltSemantics &SrcSema =
+    CGF.getContext().getFloatTypeSemantics(OrigSrcType);
+
+  // Floating-point to integer. This has undefined behavior if the source is
+  // +-Inf, NaN, or doesn't fit into the destination type (after truncation
+  // to an integer).
+  unsigned Width = CGF.getContext().getIntWidth(DstType);
+  bool Unsigned = DstType->isUnsignedIntegerOrEnumerationType();
+
+  APSInt Min = APSInt::getMinValue(Width, Unsigned);
+  APFloat MinSrc(SrcSema, APFloat::uninitialized);
+  if (MinSrc.convertFromAPInt(Min, !Unsigned, APFloat::rmTowardZero) &
+      APFloat::opOverflow)
+    // Don't need an overflow check for lower bound. Just check for
+    // -Inf/NaN.
+    MinSrc = APFloat::getInf(SrcSema, true);
+  else
+    // Find the largest value which is too small to represent (before
+    // truncation toward zero).
+    MinSrc.subtract(APFloat(SrcSema, 1), APFloat::rmTowardNegative);
+
+  APSInt Max = APSInt::getMaxValue(Width, Unsigned);
+  APFloat MaxSrc(SrcSema, APFloat::uninitialized);
+  if (MaxSrc.convertFromAPInt(Max, !Unsigned, APFloat::rmTowardZero) &
+      APFloat::opOverflow)
+    // Don't need an overflow check for upper bound. Just check for
+    // +Inf/NaN.
+    MaxSrc = APFloat::getInf(SrcSema, false);
+  else
+    // Find the smallest value which is too large to represent (before
+    // truncation toward zero).
+    MaxSrc.add(APFloat(SrcSema, 1), APFloat::rmTowardPositive);
+
+  // If we're converting from __half, convert the range to float to match
+  // the type of src.
+  if (OrigSrcType->isHalfType()) {
+    const llvm::fltSemantics &Sema =
+      CGF.getContext().getFloatTypeSemantics(SrcType);
+    bool IsInexact;
+    MinSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact);
+    MaxSrc.convert(Sema, APFloat::rmTowardZero, &IsInexact);
+  }
+
+  llvm::Value *GE =
+    Builder.CreateFCmpOGT(Src, llvm::ConstantFP::get(VMContext, MinSrc));
+  llvm::Value *LE =
+    Builder.CreateFCmpOLT(Src, llvm::ConstantFP::get(VMContext, MaxSrc));
+  Check = Builder.CreateAnd(GE, LE);
 
   llvm::Constant *StaticArgs[] = {CGF.EmitCheckSourceLocation(Loc),
                                   CGF.EmitCheckTypeDescriptor(OrigSrcType),
@@ -1205,17 +1172,25 @@ Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
   // TODO(leonardchan): When necessary, add another if statement checking for
   // conversions to fixed point types from other types.
   if (SrcType->isFixedPointType()) {
-    if (DstType->isFixedPointType()) {
-      return EmitFixedPointConversion(Src, SrcType, DstType, Loc);
-    } else if (DstType->isBooleanType()) {
+    if (DstType->isBooleanType())
+      // It is important that we check this before checking if the dest type is
+      // an integer because booleans are technically integer types.
       // We do not need to check the padding bit on unsigned types if unsigned
       // padding is enabled because overflow into this bit is undefined
       // behavior.
       return Builder.CreateIsNotNull(Src, "tobool");
-    }
+    if (DstType->isFixedPointType() || DstType->isIntegerType())
+      return EmitFixedPointConversion(Src, SrcType, DstType, Loc);
+
+    llvm_unreachable(
+        "Unhandled scalar conversion from a fixed point type to another type.");
+  } else if (DstType->isFixedPointType()) {
+    if (SrcType->isIntegerType())
+      // This also includes converting booleans and enums to fixed point types.
+      return EmitFixedPointConversion(Src, SrcType, DstType, Loc);
 
     llvm_unreachable(
-        "Unhandled scalar conversion involving a fixed point type.");
+        "Unhandled scalar conversion to a fixed point type from another type.");
   }
 
   QualType NoncanonicalSrcType = SrcType;
@@ -1351,9 +1326,12 @@ Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
   llvm::Type *ResTy = DstTy;
 
   // An overflowing conversion has undefined behavior if either the source type
-  // or the destination type is a floating-point type.
+  // or the destination type is a floating-point type. However, we consider the
+  // range of representable values for all floating-point types to be
+  // [-inf,+inf], so no overflow can ever happen when the destination type is a
+  // floating-point type.
   if (CGF.SanOpts.has(SanitizerKind::FloatCastOverflow) &&
-      (OrigSrcType->isFloatingType() || DstType->isFloatingType()))
+      OrigSrcType->isFloatingType())
     EmitFloatConversionCheck(OrigSrc, OrigSrcType, Src, SrcType, DstType, DstTy,
                              Loc);
 
@@ -1423,17 +1401,21 @@ Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
 Value *ScalarExprEmitter::EmitFixedPointConversion(Value *Src, QualType SrcTy,
                                                    QualType DstTy,
                                                    SourceLocation Loc) {
-  using llvm::APInt;
-  using llvm::ConstantInt;
-  using llvm::Value;
-
-  assert(SrcTy->isFixedPointType());
-  assert(DstTy->isFixedPointType());
-
   FixedPointSemantics SrcFPSema =
       CGF.getContext().getFixedPointSemantics(SrcTy);
   FixedPointSemantics DstFPSema =
       CGF.getContext().getFixedPointSemantics(DstTy);
+  return EmitFixedPointConversion(Src, SrcFPSema, DstFPSema, Loc,
+                                  DstTy->isIntegerType());
+}
+
+Value *ScalarExprEmitter::EmitFixedPointConversion(
+    Value *Src, FixedPointSemantics &SrcFPSema, FixedPointSemantics &DstFPSema,
+    SourceLocation Loc, bool DstIsInteger) {
+  using llvm::APInt;
+  using llvm::ConstantInt;
+  using llvm::Value;
+
   unsigned SrcWidth = SrcFPSema.getWidth();
   unsigned DstWidth = DstFPSema.getWidth();
   unsigned SrcScale = SrcFPSema.getScale();
@@ -1446,13 +1428,26 @@ Value *ScalarExprEmitter::EmitFixedPointConversion(Value *Src, QualType SrcTy,
   Value *Result = Src;
   unsigned ResultWidth = SrcWidth;
 
-  if (!DstFPSema.isSaturated()) {
-    // Downscale.
-    if (DstScale < SrcScale)
-      Result = SrcIsSigned ?
-          Builder.CreateAShr(Result, SrcScale - DstScale, "downscale") :
-          Builder.CreateLShr(Result, SrcScale - DstScale, "downscale");
+  // Downscale.
+  if (DstScale < SrcScale) {
+    // When converting to integers, we round towards zero. For negative numbers,
+    // right shifting rounds towards negative infinity. In this case, we can
+    // just round up before shifting.
+    if (DstIsInteger && SrcIsSigned) {
+      Value *Zero = llvm::Constant::getNullValue(Result->getType());
+      Value *IsNegative = Builder.CreateICmpSLT(Result, Zero);
+      Value *LowBits = ConstantInt::get(
+          CGF.getLLVMContext(), APInt::getLowBitsSet(ResultWidth, SrcScale));
+      Value *Rounded = Builder.CreateAdd(Result, LowBits);
+      Result = Builder.CreateSelect(IsNegative, Rounded, Result);
+    }
 
+    Result = SrcIsSigned
+                 ? Builder.CreateAShr(Result, SrcScale - DstScale, "downscale")
+                 : Builder.CreateLShr(Result, SrcScale - DstScale, "downscale");
+  }
+
+  if (!DstFPSema.isSaturated()) {
     // Resize.
     Result = Builder.CreateIntCast(Result, DstIntTy, SrcIsSigned, "resize");
 
@@ -1462,14 +1457,11 @@ Value *ScalarExprEmitter::EmitFixedPointConversion(Value *Src, QualType SrcTy,
   } else {
     // Adjust the number of fractional bits.
     if (DstScale > SrcScale) {
-      ResultWidth = SrcWidth + DstScale - SrcScale;
+      // Compare to DstWidth to prevent resizing twice.
+      ResultWidth = std::max(SrcWidth + DstScale - SrcScale, DstWidth);
       llvm::Type *UpscaledTy = Builder.getIntNTy(ResultWidth);
       Result = Builder.CreateIntCast(Result, UpscaledTy, SrcIsSigned, "resize");
       Result = Builder.CreateShl(Result, DstScale - SrcScale, "upscale");
-    } else if (DstScale < SrcScale) {
-      Result = SrcIsSigned ?
-          Builder.CreateAShr(Result, SrcScale - DstScale, "downscale") :
-          Builder.CreateLShr(Result, SrcScale - DstScale, "downscale");
     }
 
     // Handle saturation.
@@ -1493,7 +1485,8 @@ Value *ScalarExprEmitter::EmitFixedPointConversion(Value *Src, QualType SrcTy,
     }
 
     // Resize the integer part to get the final destination size.
-    Result = Builder.CreateIntCast(Result, DstIntTy, SrcIsSigned, "resize");
+    if (ResultWidth != DstWidth)
+      Result = Builder.CreateIntCast(Result, DstIntTy, SrcIsSigned, "resize");
   }
   return Result;
 }
@@ -1978,6 +1971,15 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
     return EmitLoadOfLValue(LV, CE->getExprLoc());
   }
 
+  case CK_LValueToRValueBitCast: {
+    LValue SourceLVal = CGF.EmitLValue(E);
+    Address Addr = Builder.CreateElementBitCast(SourceLVal.getAddress(),
+                                                CGF.ConvertTypeForMem(DestTy));
+    LValue DestLV = CGF.MakeAddrLValue(Addr, DestTy);
+    DestLV.setTBAAInfo(TBAAAccessInfo::getMayAliasInfo());
+    return EmitLoadOfLValue(DestLV, CE->getExprLoc());
+  }
+
   case CK_CPointerToObjCPointerCast:
   case CK_BlockPointerToObjCPointerCast:
   case CK_AnyPointerToBlockPointerCast:
@@ -2017,6 +2019,12 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
       }
     }
 
+    // Update heapallocsite metadata when there is an explicit cast.
+    if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(Src))
+      if (CI->getMetadata("heapallocsite") && isa<ExplicitCastExpr>(CE))
+          CGF.getDebugInfo()->
+              addHeapAllocSiteMetadata(CI, CE->getType(), CE->getExprLoc());
+
     return Builder.CreateBitCast(Src, DstTy);
   }
   case CK_AddressSpaceConversion: {
@@ -2087,14 +2095,14 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
 
   case CK_NullToPointer:
     if (MustVisitNullValue(E))
-      (void) Visit(E);
+      CGF.EmitIgnoredExpr(E);
 
     return CGF.CGM.getNullPointer(cast<llvm::PointerType>(ConvertType(DestTy)),
                               DestTy);
 
   case CK_NullToMemberPointer: {
     if (MustVisitNullValue(E))
-      (void) Visit(E);
+      CGF.EmitIgnoredExpr(E);
 
     const MemberPointerType *MPT = CE->getType()->getAs<MemberPointerType>();
     return CGF.CGM.getCXXABI().EmitNullMemberPointer(MPT);
@@ -2200,6 +2208,21 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
     return EmitScalarConversion(Visit(E), E->getType(), DestTy,
                                 CE->getExprLoc());
 
+  case CK_FixedPointToIntegral:
+    assert(E->getType()->isFixedPointType() &&
+           "Expected src type to be fixed point type");
+    assert(DestTy->isIntegerType() && "Expected dest type to be an integer");
+    return EmitScalarConversion(Visit(E), E->getType(), DestTy,
+                                CE->getExprLoc());
+
+  case CK_IntegralToFixedPoint:
+    assert(E->getType()->isIntegerType() &&
+           "Expected src type to be an integer");
+    assert(DestTy->isFixedPointType() &&
+           "Expected dest type to be fixed point type");
+    return EmitScalarConversion(Visit(E), E->getType(), DestTy,
+                                CE->getExprLoc());
+
   case CK_IntegralCast: {
     ScalarConversionOpts Opts;
     if (auto *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
@@ -2527,14 +2550,14 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
   }
 
   if (atomicPHI) {
-    llvm::BasicBlock *opBB = Builder.GetInsertBlock();
+    llvm::BasicBlock *curBlock = Builder.GetInsertBlock();
     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
     auto Pair = CGF.EmitAtomicCompareExchange(
         LV, RValue::get(atomicPHI), RValue::get(value), E->getExprLoc());
     llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), type);
     llvm::Value *success = Pair.second;
-    atomicPHI->addIncoming(old, opBB);
-    Builder.CreateCondBr(success, contBB, opBB);
+    atomicPHI->addIncoming(old, curBlock);
+    Builder.CreateCondBr(success, contBB, atomicPHI->getParent());
     Builder.SetInsertPoint(contBB);
     return isPre ? value : input;
   }
@@ -2881,14 +2904,14 @@ LValue ScalarExprEmitter::EmitCompoundAssignLValue(
                                 Loc, ScalarConversionOpts(CGF.SanOpts));
 
   if (atomicPHI) {
-    llvm::BasicBlock *opBB = Builder.GetInsertBlock();
+    llvm::BasicBlock *curBlock = Builder.GetInsertBlock();
     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
     auto Pair = CGF.EmitAtomicCompareExchange(
         LHSLV, RValue::get(atomicPHI), RValue::get(Result), E->getExprLoc());
     llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), LHSTy);
     llvm::Value *success = Pair.second;
-    atomicPHI->addIncoming(old, opBB);
-    Builder.CreateCondBr(success, contBB, opBB);
+    atomicPHI->addIncoming(old, curBlock);
+    Builder.CreateCondBr(success, contBB, atomicPHI->getParent());
     Builder.SetInsertPoint(contBB);
     return LHSLV;
   }
@@ -2908,7 +2931,7 @@ LValue ScalarExprEmitter::EmitCompoundAssignLValue(
 Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E,
                       Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) {
   bool Ignore = TestAndClearIgnoreResultAssign();
-  Value *RHS;
+  Value *RHS = nullptr;
   LValue LHS = EmitCompoundAssignLValue(E, Func, RHS);
 
   // If the result is clearly ignored, return now.
@@ -3090,7 +3113,8 @@ Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
   llvm::Type *argTypes[] = { CGF.Int64Ty, CGF.Int64Ty, Int8Ty, Int8Ty };
   llvm::FunctionType *handlerTy =
       llvm::FunctionType::get(CGF.Int64Ty, argTypes, true);
-  llvm::Value *handler = CGF.CGM.CreateRuntimeFunction(handlerTy, *handlerName);
+  llvm::FunctionCallee handler =
+      CGF.CGM.CreateRuntimeFunction(handlerTy, *handlerName);
 
   // Sign extend the args to 64-bit, so that we can use the same handler for
   // all types of overflow.
@@ -3338,9 +3362,119 @@ Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) {
     return propagateFMFlags(V, op);
   }
 
+  if (op.isFixedPointBinOp())
+    return EmitFixedPointBinOp(op);
+
   return Builder.CreateAdd(op.LHS, op.RHS, "add");
 }
 
+/// The resulting value must be calculated with exact precision, so the operands
+/// may not be the same type.
+Value *ScalarExprEmitter::EmitFixedPointBinOp(const BinOpInfo &op) {
+  using llvm::APSInt;
+  using llvm::ConstantInt;
+
+  const auto *BinOp = cast<BinaryOperator>(op.E);
+
+  // The result is a fixed point type and at least one of the operands is fixed
+  // point while the other is either fixed point or an int. This resulting type
+  // should be determined by Sema::handleFixedPointConversions().
+  QualType ResultTy = op.Ty;
+  QualType LHSTy = BinOp->getLHS()->getType();
+  QualType RHSTy = BinOp->getRHS()->getType();
+  ASTContext &Ctx = CGF.getContext();
+  Value *LHS = op.LHS;
+  Value *RHS = op.RHS;
+
+  auto LHSFixedSema = Ctx.getFixedPointSemantics(LHSTy);
+  auto RHSFixedSema = Ctx.getFixedPointSemantics(RHSTy);
+  auto ResultFixedSema = Ctx.getFixedPointSemantics(ResultTy);
+  auto CommonFixedSema = LHSFixedSema.getCommonSemantics(RHSFixedSema);
+
+  // Convert the operands to the full precision type.
+  Value *FullLHS = EmitFixedPointConversion(LHS, LHSFixedSema, CommonFixedSema,
+                                            BinOp->getExprLoc());
+  Value *FullRHS = EmitFixedPointConversion(RHS, RHSFixedSema, CommonFixedSema,
+                                            BinOp->getExprLoc());
+
+  // Perform the actual addition.
+  Value *Result;
+  switch (BinOp->getOpcode()) {
+  case BO_Add: {
+    if (ResultFixedSema.isSaturated()) {
+      llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
+                                    ? llvm::Intrinsic::sadd_sat
+                                    : llvm::Intrinsic::uadd_sat;
+      Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
+    } else {
+      Result = Builder.CreateAdd(FullLHS, FullRHS);
+    }
+    break;
+  }
+  case BO_Sub: {
+    if (ResultFixedSema.isSaturated()) {
+      llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
+                                    ? llvm::Intrinsic::ssub_sat
+                                    : llvm::Intrinsic::usub_sat;
+      Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
+    } else {
+      Result = Builder.CreateSub(FullLHS, FullRHS);
+    }
+    break;
+  }
+  case BO_LT:
+    return CommonFixedSema.isSigned() ? Builder.CreateICmpSLT(FullLHS, FullRHS)
+                                      : Builder.CreateICmpULT(FullLHS, FullRHS);
+  case BO_GT:
+    return CommonFixedSema.isSigned() ? Builder.CreateICmpSGT(FullLHS, FullRHS)
+                                      : Builder.CreateICmpUGT(FullLHS, FullRHS);
+  case BO_LE:
+    return CommonFixedSema.isSigned() ? Builder.CreateICmpSLE(FullLHS, FullRHS)
+                                      : Builder.CreateICmpULE(FullLHS, FullRHS);
+  case BO_GE:
+    return CommonFixedSema.isSigned() ? Builder.CreateICmpSGE(FullLHS, FullRHS)
+                                      : Builder.CreateICmpUGE(FullLHS, FullRHS);
+  case BO_EQ:
+    // For equality operations, we assume any padding bits on unsigned types are
+    // zero'd out. They could be overwritten through non-saturating operations
+    // that cause overflow, but this leads to undefined behavior.
+    return Builder.CreateICmpEQ(FullLHS, FullRHS);
+  case BO_NE:
+    return Builder.CreateICmpNE(FullLHS, FullRHS);
+  case BO_Mul:
+  case BO_Div:
+  case BO_Shl:
+  case BO_Shr:
+  case BO_Cmp:
+  case BO_LAnd:
+  case BO_LOr:
+  case BO_MulAssign:
+  case BO_DivAssign:
+  case BO_AddAssign:
+  case BO_SubAssign:
+  case BO_ShlAssign:
+  case BO_ShrAssign:
+    llvm_unreachable("Found unimplemented fixed point binary operation");
+  case BO_PtrMemD:
+  case BO_PtrMemI:
+  case BO_Rem:
+  case BO_Xor:
+  case BO_And:
+  case BO_Or:
+  case BO_Assign:
+  case BO_RemAssign:
+  case BO_AndAssign:
+  case BO_XorAssign:
+  case BO_OrAssign:
+  case BO_Comma:
+    llvm_unreachable("Found unsupported binary operation for fixed point types.");
+  }
+
+  // Convert to the result type.
+  return EmitFixedPointConversion(Result, CommonFixedSema, ResultFixedSema,
+                                  BinOp->getExprLoc());
+}
+
 Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
   // The LHS is always a pointer if either side is.
   if (!op.LHS->getType()->isPointerTy()) {
@@ -3372,6 +3506,9 @@ Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
       return propagateFMFlags(V, op);
     }
 
+    if (op.isFixedPointBinOp())
+      return EmitFixedPointBinOp(op);
+
     return Builder.CreateSub(op.LHS, op.RHS, "sub");
   }
 
@@ -3450,7 +3587,8 @@ Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) {
 
   bool SanitizeBase = CGF.SanOpts.has(SanitizerKind::ShiftBase) &&
                       Ops.Ty->hasSignedIntegerRepresentation() &&
-                      !CGF.getLangOpts().isSignedOverflowDefined();
+                      !CGF.getLangOpts().isSignedOverflowDefined() &&
+                      !CGF.getLangOpts().CPlusPlus2a;
   bool SanitizeExponent = CGF.SanOpts.has(SanitizerKind::ShiftExponent);
   // OpenCL 6.3j: shift values are effectively % word size of LHS.
   if (CGF.getLangOpts().OpenCL)
@@ -3591,8 +3729,9 @@ Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,
     Result = CGF.CGM.getCXXABI().EmitMemberPointerComparison(
                    CGF, LHS, RHS, MPT, E->getOpcode() == BO_NE);
   } else if (!LHSTy->isAnyComplexType() && !RHSTy->isAnyComplexType()) {
-    Value *LHS = Visit(E->getLHS());
-    Value *RHS = Visit(E->getRHS());
+    BinOpInfo BOInfo = EmitBinOps(E);
+    Value *LHS = BOInfo.LHS;
+    Value *RHS = BOInfo.RHS;
 
     // If AltiVec, the comparison results in a numeric type, so we use
     // intrinsics comparing vectors and giving 0 or 1 as a result
@@ -3670,7 +3809,9 @@ Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,
                                   E->getExprLoc());
     }
 
-    if (LHS->getType()->isFPOrFPVectorTy()) {
+    if (BOInfo.isFixedPointBinOp()) {
+      Result = EmitFixedPointBinOp(BOInfo);
+    } else if (LHS->getType()->isFPOrFPVectorTy()) {
       Result = Builder.CreateFCmp(FCmpOpc, LHS, RHS, "cmp");
     } else if (LHSTy->hasSignedIntegerRepresentation()) {
       Result = Builder.CreateICmp(SICmpOpc, LHS, RHS, "cmp");