[Fixed Point Arithmetic] Fixed Point Addition Constant Expression Evaluation

This patch includes logic for constant expression evaluation of fixed point additions.

Differential Revision: https://reviews.llvm.org/D55868

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@351593 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 348 insertions, 64 deletions

diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 3de7342882..19901c5af5 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -23,6 +23,7 @@
 #include "clang/AST/TemplateBase.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/CharInfo.h"
+#include "clang/Basic/FixedPoint.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SyncScope.h"
 #include "clang/Basic/TypeTraits.h"
@@ -611,6 +612,12 @@ public:
   EvaluateAsFloat(llvm::APFloat &Result, const ASTContext &Ctx,
                   SideEffectsKind AllowSideEffects = SE_NoSideEffects) const;
 
+  /// EvaluateAsFloat - Return true if this is a constant which we can fold and
+  /// convert to a fixed point value.
+  bool EvaluateAsFixedPoint(
+      EvalResult &Result, const ASTContext &Ctx,
+      SideEffectsKind AllowSideEffects = SE_NoSideEffects) const;
+
   /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
   /// constant folded without side-effects, but discard the result.
   bool isEvaluatable(const ASTContext &Ctx,
diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index 568fbf1eee..034cf1c740 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -61,6 +61,7 @@ def IntConversion : DiagGroup<"int-conversion">;
 def EnumConversion : DiagGroup<"enum-conversion">;
 def ImplicitIntConversion : DiagGroup<"implicit-int-conversion">;
 def ImplicitFloatConversion : DiagGroup<"implicit-float-conversion">;
+def ImplicitFixedPointConversion : DiagGroup<"implicit-fixed-point-conversion">;
 
 def FloatOverflowConversion : DiagGroup<"float-overflow-conversion">;
 def FloatZeroConversion : DiagGroup<"float-zero-conversion">;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 05e2d2dec2..a989675d89 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3190,6 +3190,10 @@ def warn_impcast_bitfield_precision_constant : Warning<
   "implicit truncation from %2 to bit-field changes value from %0 to %1">,
   InGroup<BitFieldConstantConversion>;
 
+def warn_impcast_fixed_point_range : Warning<
+  "implicit conversion from %0 cannot fit within the range of values for %1">,
+  InGroup<ImplicitFixedPointConversion>;
+
 def warn_impcast_literal_float_to_integer : Warning<
   "implicit conversion from %0 to %1 changes value from %2 to %3">,
   InGroup<LiteralConversion>;
diff --git a/include/clang/Basic/FixedPoint.h b/include/clang/Basic/FixedPoint.h
index 174f7cc7d0..048c8a8019 100644
--- a/include/clang/Basic/FixedPoint.h
+++ b/include/clang/Basic/FixedPoint.h
@@ -118,8 +118,21 @@ class APFixedPoint {
 
    bool getBoolValue() const { return Val.getBoolValue(); }
 
-   // Convert this number to match the semantics provided.
-   APFixedPoint convert(const FixedPointSemantics &DstSema) const;
+   // Convert this number to match the semantics provided. If the overflow
+   // parameter is provided, set this value to true or false to indicate if this
+   // operation results in an overflow.
+   APFixedPoint convert(const FixedPointSemantics &DstSema,
+                        bool *Overflow = nullptr) const;
+
+   // Perform binary operations on a fixed point type. The resulting fixed point
+   // value will be in the common, full precision semantics that can represent
+   // the precision and ranges os both input values. See convert() for an
+   // explanation of the Overflow parameter.
+   APFixedPoint add(const APFixedPoint &Other, bool *Overflow = nullptr) const;
+
+   /// Perform a unary negation (-X) on this fixed point type, taking into
+   /// account saturation if applicable.
+   APFixedPoint negate(bool *Overflow = nullptr) const;
 
    APFixedPoint shr(unsigned Amt) const {
      return APFixedPoint(Val >> Amt, Sema);
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 6fced96484..de9943653c 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -44,6 +44,7 @@
 #include "clang/AST/StmtVisitor.h"
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/Builtins.h"
+#include "clang/Basic/FixedPoint.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/raw_ostream.h"
@@ -613,6 +614,15 @@ namespace {
       }
       return *this;
     }
+
+    OptionalDiagnostic &operator<<(const APFixedPoint &FX) {
+      if (Diag) {
+        SmallVector<char, 32> Buffer;
+        FX.toString(Buffer);
+        *Diag << StringRef(Buffer.data(), Buffer.size());
+      }
+      return *this;
+    }
   };
 
   /// A cleanup, and a flag indicating whether it is lifetime-extended.
@@ -1613,6 +1623,14 @@ static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
                            EvalInfo &Info);
 static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
 
+/// Evaluate an integer or fixed point expression into an APResult.
+static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
+                                        EvalInfo &Info);
+
+/// Evaluate only a fixed point expression into an APResult.
+static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
+                               EvalInfo &Info);
+
 //===----------------------------------------------------------------------===//
 // Misc utilities
 //===----------------------------------------------------------------------===//
@@ -7493,53 +7511,27 @@ class FixedPointExprEvaluator
   FixedPointExprEvaluator(EvalInfo &info, APValue &result)
       : ExprEvaluatorBaseTy(info), Result(result) {}
 
-  bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
-    assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
-    assert(SI.isSigned() == E->getType()->isSignedFixedPointType() &&
-           "Invalid evaluation result.");
-    assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
-           "Invalid evaluation result.");
-    Result = APValue(SI);
-    return true;
-  }
-  bool Success(const llvm::APSInt &SI, const Expr *E) {
-    return Success(SI, E, Result);
-  }
-
-  bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
-    assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
-    assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
-           "Invalid evaluation result.");
-    Result = APValue(APSInt(I));
-    Result.getInt().setIsUnsigned(E->getType()->isUnsignedFixedPointType());
-    return true;
-  }
   bool Success(const llvm::APInt &I, const Expr *E) {
-    return Success(I, E, Result);
+    return Success(
+        APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E);
   }
 
-  bool Success(uint64_t Value, const Expr *E, APValue &Result) {
-    assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
-    Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
-    return true;
-  }
   bool Success(uint64_t Value, const Expr *E) {
-    return Success(Value, E, Result);
-  }
-
-  bool Success(CharUnits Size, const Expr *E) {
-    return Success(Size.getQuantity(), E);
+    return Success(
+        APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E);
   }
 
   bool Success(const APValue &V, const Expr *E) {
-    if (V.isLValue() || V.isAddrLabelDiff()) {
-      Result = V;
-      return true;
-    }
-    return Success(V.getInt(), E);
+    return Success(V.getFixedPoint(), E);
   }
 
-  bool ZeroInitialization(const Expr *E) { return Success(0, E); }
+  bool Success(const APFixedPoint &V, const Expr *E) {
+    assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
+    assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&
+           "Invalid evaluation result.");
+    Result = APValue(V);
+    return true;
+  }
 
   //===--------------------------------------------------------------------===//
   //                            Visitor Methods
@@ -7549,7 +7541,9 @@ class FixedPointExprEvaluator
     return Success(E->getValue(), E);
   }
 
+  bool VisitCastExpr(const CastExpr *E);
   bool VisitUnaryOperator(const UnaryOperator *E);
+  bool VisitBinaryOperator(const BinaryOperator *E);
 };
 } // end anonymous namespace
 
@@ -7581,6 +7575,36 @@ static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
   return true;
 }
 
+static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
+                               EvalInfo &Info) {
+  if (E->getType()->isFixedPointType()) {
+    APValue Val;
+    if (!FixedPointExprEvaluator(Info, Val).Visit(E))
+      return false;
+    if (!Val.isFixedPoint())
+      return false;
+
+    Result = Val.getFixedPoint();
+    return true;
+  }
+  return false;
+}
+
+static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
+                                        EvalInfo &Info) {
+  if (E->getType()->isIntegerType()) {
+    auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType());
+    APSInt Val;
+    if (!EvaluateInteger(E, Val, Info))
+      return false;
+    Result = APFixedPoint(Val, FXSema);
+    return true;
+  } else if (E->getType()->isFixedPointType()) {
+    return EvaluateFixedPoint(E, Result, Info);
+  }
+  return false;
+}
+
 /// Check whether the given declaration can be directly converted to an integral
 /// rvalue. If not, no diagnostic is produced; there are other things we can
 /// try.
@@ -9781,7 +9805,7 @@ bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
     APValue Val;
     if (!Evaluate(Val, Info, SubExpr))
       return false;
-    return Success(Val.getInt().getBoolValue(), E);
+    return Success(Val.getFixedPoint().getBoolValue(), E);
   }
 
   case CK_IntegralCast: {
@@ -9901,16 +9925,13 @@ bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
       return Visit(E->getSubExpr());
     case UO_Minus: {
       if (!Visit(E->getSubExpr())) return false;
-      if (!Result.isInt()) return Error(E);
-      const APSInt &Value = Result.getInt();
-      if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow()) {
-        SmallString<64> S;
-        FixedPointValueToString(S, Value,
-                                Info.Ctx.getTypeInfo(E->getType()).Width);
-        Info.CCEDiag(E, diag::note_constexpr_overflow) << S << E->getType();
-        if (Info.noteUndefinedBehavior()) return false;
-      }
-      return Success(-Value, E);
+      if (!Result.isFixedPoint())
+        return Error(E);
+      bool Overflowed;
+      APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed);
+      if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType()))
+        return false;
+      return Success(Negated, E);
     }
     case UO_LNot: {
       bool bres;
@@ -9921,6 +9942,61 @@ bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
   }
 }
 
+bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
+  const Expr *SubExpr = E->getSubExpr();
+  QualType DestType = E->getType();
+  assert(DestType->isFixedPointType() &&
+         "Expected destination type to be a fixed point type");
+  auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType);
+
+  switch (E->getCastKind()) {
+  case CK_FixedPointCast: {
+    APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
+    if (!EvaluateFixedPoint(SubExpr, Src, Info))
+      return false;
+    bool Overflowed;
+    APFixedPoint Result = Src.convert(DestFXSema, &Overflowed);
+    if (Overflowed && !HandleOverflow(Info, E, Result, DestType))
+      return false;
+    return Success(Result, E);
+  }
+  case CK_NoOp:
+  case CK_LValueToRValue:
+    return ExprEvaluatorBaseTy::VisitCastExpr(E);
+  default:
+    return Error(E);
+  }
+}
+
+bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
+  const Expr *LHS = E->getLHS();
+  const Expr *RHS = E->getRHS();
+  FixedPointSemantics ResultFXSema =
+      Info.Ctx.getFixedPointSemantics(E->getType());
+
+  APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType()));
+  if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info))
+    return false;
+  APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType()));
+  if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info))
+    return false;
+
+  switch (E->getOpcode()) {
+  case BO_Add: {
+    bool AddOverflow, ConversionOverflow;
+    APFixedPoint Result = LHSFX.add(RHSFX, &AddOverflow)
+                              .convert(ResultFXSema, &ConversionOverflow);
+    if ((AddOverflow || ConversionOverflow) &&
+        !HandleOverflow(Info, E, Result, E->getType()))
+      return false;
+    return Success(Result, E);
+  }
+  default:
+    return false;
+  }
+  llvm_unreachable("Should've exited before this");
+}
+
 //===----------------------------------------------------------------------===//
 // Float Evaluation
 //===----------------------------------------------------------------------===//
@@ -10932,6 +11008,23 @@ static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
   return true;
 }
 
+static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
+                                 const ASTContext &Ctx,
+                                 Expr::SideEffectsKind AllowSideEffects,
+                                 EvalInfo &Info) {
+  if (!E->getType()->isFixedPointType())
+    return false;
+
+  if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info))
+    return false;
+
+  if (!ExprResult.Val.isFixedPoint() ||
+      hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
+    return false;
+
+  return true;
+}
+
 /// EvaluateAsRValue - Return true if this is a constant which we can fold using
 /// any crazy technique (that has nothing to do with language standards) that
 /// we want to.  If this function returns true, it returns the folded constant
@@ -10957,6 +11050,12 @@ bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
   return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info);
 }
 
+bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
+                                SideEffectsKind AllowSideEffects) const {
+  EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
+  return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info);
+}
+
 bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
                            SideEffectsKind AllowSideEffects) const {
   if (!getType()->isRealFloatingType())
diff --git a/lib/Basic/FixedPoint.cpp b/lib/Basic/FixedPoint.cpp
index e3cffe628f..33caeb92e8 100644
--- a/lib/Basic/FixedPoint.cpp
+++ b/lib/Basic/FixedPoint.cpp
@@ -16,11 +16,14 @@
 
 namespace clang {
 
-APFixedPoint APFixedPoint::convert(const FixedPointSemantics &DstSema) const {
+APFixedPoint APFixedPoint::convert(const FixedPointSemantics &DstSema,
+                                   bool *Overflow) const {
   llvm::APSInt NewVal = Val;
   unsigned DstWidth = DstSema.getWidth();
   unsigned DstScale = DstSema.getScale();
   bool Upscaling = DstScale > getScale();
+  if (Overflow)
+    *Overflow = false;
 
   if (Upscaling) {
     NewVal = NewVal.extend(NewVal.getBitWidth() + DstScale - getScale());
@@ -29,18 +32,28 @@ APFixedPoint APFixedPoint::convert(const FixedPointSemantics &DstSema) const {
     NewVal >>= (getScale() - DstScale);
   }
 
-  if (DstSema.isSaturated()) {
-    auto Mask = llvm::APInt::getBitsSetFrom(
-        NewVal.getBitWidth(),
-        std::min(DstScale + DstSema.getIntegralBits(), NewVal.getBitWidth()));
-    llvm::APInt Masked(NewVal & Mask);
+  auto Mask = llvm::APInt::getBitsSetFrom(
+      NewVal.getBitWidth(),
+      std::min(DstScale + DstSema.getIntegralBits(), NewVal.getBitWidth()));
+  llvm::APInt Masked(NewVal & Mask);
 
-    // Change in the bits above the sign
-    if (!(Masked == Mask || Masked == 0))
+  // Change in the bits above the sign
+  if (!(Masked == Mask || Masked == 0)) {
+    // Found overflow in the bits above the sign
+    if (DstSema.isSaturated())
       NewVal = NewVal.isNegative() ? Mask : ~Mask;
+    else if (Overflow)
+      *Overflow = true;
+  }
 
-    if (!DstSema.isSigned() && NewVal.isNegative())
+  // If the dst semantics are unsigned, but our value is signed and negative, we
+  // clamp to zero.
+  if (!DstSema.isSigned() && NewVal.isSigned() && NewVal.isNegative()) {
+    // Found negative overflow for unsigned result
+    if (DstSema.isSaturated())
       NewVal = 0;
+    else if (Overflow)
+      *Overflow = true;
   }
 
   NewVal = NewVal.extOrTrunc(DstWidth);
@@ -137,6 +150,30 @@ FixedPointSemantics FixedPointSemantics::getCommonSemantics(
                              ResultIsSaturated, ResultHasUnsignedPadding);
 }
 
+APFixedPoint APFixedPoint::add(const APFixedPoint &Other,
+                               bool *Overflow) const {
+  auto CommonFXSema = Sema.getCommonSemantics(Other.getSemantics());
+  APFixedPoint ConvertedThis = convert(CommonFXSema);
+  APFixedPoint ConvertedOther = Other.convert(CommonFXSema);
+  llvm::APSInt ThisVal = ConvertedThis.getValue();
+  llvm::APSInt OtherVal = ConvertedOther.getValue();
+  bool Overflowed = false;
+
+  llvm::APSInt Result;
+  if (CommonFXSema.isSaturated()) {
+    Result = CommonFXSema.isSigned() ? ThisVal.sadd_sat(OtherVal)
+                                     : ThisVal.uadd_sat(OtherVal);
+  } else {
+    Result = ThisVal.isSigned() ? ThisVal.sadd_ov(OtherVal, Overflowed)
+                                : ThisVal.uadd_ov(OtherVal, Overflowed);
+  }
+
+  if (Overflow)
+    *Overflow = Overflowed;
+
+  return APFixedPoint(Result, CommonFXSema);
+}
+
 void APFixedPoint::toString(llvm::SmallVectorImpl<char> &Str) const {
   llvm::APSInt Val = getValue();
   unsigned Scale = getScale();
@@ -164,4 +201,22 @@ void APFixedPoint::toString(llvm::SmallVectorImpl<char> &Str) const {
   } while (FractPart != 0);
 }
 
+APFixedPoint APFixedPoint::negate(bool *Overflow) const {
+  if (!isSaturated()) {
+    if (Overflow)
+      *Overflow =
+          (!isSigned() && Val != 0) || (isSigned() && Val.isMinSignedValue());
+    return APFixedPoint(-Val, Sema);
+  }
+
+  // We never overflow for saturation
+  if (Overflow)
+    *Overflow = false;
+
+  if (isSigned())
+    return Val.isMinSignedValue() ? getMax(Sema) : APFixedPoint(-Val, Sema);
+  else
+    return APFixedPoint(Sema);
+}
+
 }  // namespace clang
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 8dc1fdb769..3bd911b53c 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -11013,6 +11013,28 @@ CheckImplicitConversion(Sema &S, Expr *E, QualType T, SourceLocation CC,
     return;
   }
 
+  if (Source->isFixedPointType()) {
+    // TODO: Only CK_FixedPointCast is supported now. The other valid casts
+    // should be accounted for here.
+    if (Target->isFixedPointType()) {
+      Expr::EvalResult Result;
+      if (E->EvaluateAsFixedPoint(Result, S.Context,
+                                  Expr::SE_AllowSideEffects)) {
+        APFixedPoint Value = Result.Val.getFixedPoint();
+        APFixedPoint MaxVal = S.Context.getFixedPointMax(T);
+        APFixedPoint MinVal = S.Context.getFixedPointMin(T);
+        if (Value > MaxVal || Value < MinVal) {
+          S.DiagRuntimeBehavior(E->getExprLoc(), E,
+                                S.PDiag(diag::warn_impcast_fixed_point_range)
+                                    << Value.toString() << T
+                                    << E->getSourceRange()
+                                    << clang::SourceRange(CC));
+          return;
+        }
+      }
+    }
+  }
+
   DiagnoseNullConversion(S, E, T, CC);
 
   S.DiscardMisalignedMemberAddress(Target, E);
diff --git a/test/Frontend/fixed_point_add.c b/test/Frontend/fixed_point_add.c
index ff3cdb9d4e..be3d5a8f5e 100644
--- a/test/Frontend/fixed_point_add.c
+++ b/test/Frontend/fixed_point_add.c
@@ -1,5 +1,48 @@
-// RUN: %clang_cc1 -ffixed-point -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,SIGNED
-// RUN: %clang_cc1 -ffixed-point -fpadding-on-unsigned-fixed-point -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,UNSIGNED
+// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,SIGNED
+// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -fpadding-on-unsigned-fixed-point -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,UNSIGNED
+
+// Addition between different fixed point types
+short _Accum sa_const = 1.0hk + 2.0hk;  // CHECK-DAG: @sa_const  = {{.*}}global i16 384, align 2
+_Accum a_const = 1.0hk + 2.0k;          // CHECK-DAG: @a_const   = {{.*}}global i32 98304, align 4
+long _Accum la_const = 1.0hk + 2.0lk;   // CHECK-DAG: @la_const  = {{.*}}global i64 6442450944, align 8
+short _Accum sa_const2 = 0.5hr + 2.0hk; // CHECK-DAG: @sa_const2  = {{.*}}global i16 320, align 2
+short _Accum sa_const3 = 0.5r + 2.0hk;  // CHECK-DAG: @sa_const3  = {{.*}}global i16 320, align 2
+short _Accum sa_const4 = 0.5lr + 2.0hk; // CHECK-DAG: @sa_const4  = {{.*}}global i16 320, align 2
+
+// Unsigned addition
+unsigned short _Accum usa_const = 1.0uhk + 2.0uhk;
+// CHECK-SIGNED-DAG:   @usa_const = {{.*}}global i16 768, align 2
+// CHECK-UNSIGNED-DAG: @usa_const = {{.*}}global i16 384, align 2
+
+// Unsigned + signed
+short _Accum sa_const5 = 1.0uhk + 2.0hk;
+// CHECK-DAG: @sa_const5 = {{.*}}global i16 384, align 2
+
+// Addition with negative number
+short _Accum sa_const6 = 0.5hr + (-2.0hk);
+// CHECK-DAG: @sa_const6 = {{.*}}global i16 -192, align 2
+
+// Int addition
+unsigned short _Accum usa_const2 = 2 + 0.5uhk;
+// CHECK-SIGNED-DAG:   @usa_const2 = {{.*}}global i16 640, align 2
+// CHECK-UNSIGNED-DAG: @usa_const2 = {{.*}}global i16 320, align 2
+short _Accum sa_const7 = 2 + (-0.5hk);   // CHECK-DAG: @sa_const7 = {{.*}}global i16 192, align 2
+short _Accum sa_const8 = 257 + (-2.0hk); // CHECK-DAG: @sa_const8 = {{.*}}global i16 32640, align 2
+long _Fract lf_const = -0.5lr + 1;       // CHECK-DAG: @lf_const  = {{.*}}global i32 1073741824, align 4
+
+// Saturated addition
+_Sat short _Accum sat_sa_const = (_Sat short _Accum)128.0hk + 128.0hk;
+// CHECK-DAG: @sat_sa_const = {{.*}}global i16 32767, align 2
+_Sat unsigned short _Accum sat_usa_const = (_Sat unsigned short _Accum)128.0uhk + 128.0uhk;
+// CHECK-SIGNED-DAG:   @sat_usa_const = {{.*}}global i16 65535, align 2
+// CHECK-UNSIGNED-DAG: @sat_usa_const = {{.*}}global i16 32767, align 2
+_Sat short _Accum sat_sa_const2 = (_Sat short _Accum)128.0hk + 128;
+// CHECK-DAG: @sat_sa_const2 = {{.*}}global i16 32767, align 2
+_Sat unsigned short _Accum sat_usa_const2 = (_Sat unsigned short _Accum)128.0uhk + 128;
+// CHECK-SIGNED-DAG:   @sat_usa_const2 = {{.*}}global i16 65535, align 2
+// CHECK-UNSIGNED-DAG: @sat_usa_const2 = {{.*}}global i16 32767, align 2
+_Sat unsigned short _Accum sat_usa_const3 = (_Sat unsigned short _Accum)0.5uhk + (-2);
+// CHECK-DAG:   @sat_usa_const3 = {{.*}}global i16 0, align 2
 
 void SignedAddition() {
   // CHECK-LABEL: SignedAddition
diff --git a/test/Frontend/fixed_point_conversions.c b/test/Frontend/fixed_point_conversions.c
index 22cde0eb69..0b36d9d0ca 100644
--- a/test/Frontend/fixed_point_conversions.c
+++ b/test/Frontend/fixed_point_conversions.c
@@ -1,5 +1,39 @@
-// RUN: %clang_cc1 -ffixed-point -S -emit-llvm %s -o - | FileCheck %s -check-prefix=DEFAULT
-// RUN: %clang_cc1 -ffixed-point -S -emit-llvm %s -o - -fpadding-on-unsigned-fixed-point | FileCheck %s -check-prefix=SAME
+// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -S -emit-llvm %s -o - | FileCheck %s -check-prefix=DEFAULT
+// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -S -emit-llvm %s -o - -fpadding-on-unsigned-fixed-point | FileCheck %s -check-prefix=SAME
+
+// Between different fixed point types
+short _Accum sa_const = 2.5hk; // DEFAULT-DAG: @sa_const  = {{.*}}global i16 320, align 2
+_Accum a_const = 2.5hk;        // DEFAULT-DAG: @a_const   = {{.*}}global i32 81920, align 4
+short _Accum sa_const2 = 2.5k; // DEFAULT-DAG: @sa_const2 = {{.*}}global i16 320, align 2
+
+short _Accum sa_from_f_const = 0.5r; // DEFAULT-DAG: sa_from_f_const = {{.*}}global i16 64, align 2
+_Fract f_from_sa_const = 0.5hk;      // DEFAULT-DAG: f_from_sa_const = {{.*}}global i16 16384, align 2
+
+unsigned short _Accum usa_const = 2.5uk;
+unsigned _Accum ua_const = 2.5uhk;
+// DEFAULT-DAG: @usa_const  = {{.*}}global i16 640, align 2
+// DEFAULT-DAG: @ua_const   = {{.*}}global i32 163840, align 4
+// SAME-DAG:    @usa_const  = {{.*}}global i16 320, align 2
+// SAME-DAG:    @ua_const   = {{.*}}global i32 81920, align 4
+
+// Signedness
+unsigned short _Accum usa_const2 = 2.5hk;
+// DEFAULT-DAG: @usa_const2  = {{.*}}global i16 640, align 2
+// SAME-DAG:    @usa_const2  = {{.*}}global i16 320, align 2
+short _Accum sa_const3 = 2.5hk; // DEFAULT-DAG: @sa_const3 = {{.*}}global i16 320, align 2
+
+// Overflow (this is undefined but allowed)
+short _Accum sa_const4 = 256.0k;
+
+// Saturation
+_Sat short _Accum sat_sa_const = 2.5hk;   // DEFAULT-DAG: @sat_sa_const  = {{.*}}global i16 320, align 2
+_Sat short _Accum sat_sa_const2 = 256.0k; // DEFAULT-DAG: @sat_sa_const2 = {{.*}}global i16 32767, align 2
+_Sat unsigned short _Accum sat_usa_const = -1.0hk;
+// DEFAULT-DAG: @sat_usa_const = {{.*}}global i16 0, align 2
+// SAME-DAG:    @sat_usa_const = {{.*}}global i16 0, align 2
+_Sat unsigned short _Accum sat_usa_const2 = 256.0k;
+// DEFAULT-DAG: @sat_usa_const2 = {{.*}}global i16 -1, align 2
+// SAME-DAG:    @sat_usa_const2 = {{.*}}global i16 32767, align 2
 
 void TestFixedPointCastSameType() {
   _Accum a = 2.5k;
diff --git a/test/Frontend/fixed_point_errors.c b/test/Frontend/fixed_point_errors.c
index 41427e3431..43c5057257 100644
--- a/test/Frontend/fixed_point_errors.c
+++ b/test/Frontend/fixed_point_errors.c
@@ -232,3 +232,9 @@ void CheckSuffixOnIntegerLiterals() {
   auto auto_accum = 0k;  // expected-error{{invalid suffix 'k' on integer constant}}
                          // expected-warning@-1{{type specifier missing, defaults to 'int'}}
 }
+
+// Overflow
+short _Accum sa_const = 256.0k;   // expected-warning{{implicit conversion from 256.0 cannot fit within the range of values for 'short _Accum'}}
+short _Fract sf_const = 1.0hk;    // expected-warning{{implicit conversion from 1.0 cannot fit within the range of values for 'short _Fract'}}
+unsigned _Accum ua_const = -1.0k; // expected-warning{{implicit conversion from -1.0 cannot fit within the range of values for 'unsigned _Accum'}}
+short _Accum sa_const2 = 128.0k + 128.0k; // expected-warning{{implicit conversion from 256.0 cannot fit within the range of values for 'short _Accum'}}