[clang][bytecode] Implement fixed-point add (#110405)

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -1528,6 +1528,9 @@ bool Compiler<Emitter>::VisitFixedPointBinOp(const BinaryOperator *E) {
   case BO_GE:
     return this->emitGEFixedPoint(E);
 #endif
+  case BO_Add:
+    return this->emitAddFixedPoint(E);
+
   default:
     return this->emitInvalid(E);
   }

clang/lib/AST/ByteCode/FixedPoint.h

@@ -47,15 +47,28 @@ class FixedPoint final {
   void print(llvm::raw_ostream &OS) const { OS << V; }
 
   APValue toAPValue(const ASTContext &) const { return APValue(V); }
-  APSInt toAPSInt(unsigned BitWidth) const { return V.getValue(); }
+  APSInt toAPSInt(unsigned BitWidth = 0) const { return V.getValue(); }
 
   unsigned bitWidth() const { return V.getWidth(); }
   bool isSigned() const { return V.isSigned(); }
+  bool isZero() const { return V.getValue().isZero(); }
+  bool isNegative() const { return V.getValue().isNegative(); }
+  bool isPositive() const { return V.getValue().isNonNegative(); }
+  bool isMin() const {
+    return V.getValue() == APSInt::getMinValue(V.getSemantics().getWidth(),
+                                               !V.getSemantics().isSigned());
+  }
+
+  FixedPoint truncate(unsigned BitWidth) const { return *this; }
 
   llvm::APFloat toFloat(const llvm::fltSemantics *Sem) const {
     return V.convertToFloat(*Sem);
   }
 
+  std::string toDiagnosticString(const ASTContext &Ctx) const {
+    return V.toString();
+  }
+
   ComparisonCategoryResult compare(const FixedPoint &Other) const {
     if (Other.V == V)
       return ComparisonCategoryResult::Equal;
@@ -67,6 +80,27 @@ class FixedPoint final {
     *R = FixedPoint(A.V.negate(&Overflow));
     return Overflow;
   }
+
+  static bool add(const FixedPoint A, const FixedPoint B, unsigned Bits,
+                  FixedPoint *R) {
+    bool Overflow = false;
+    *R = FixedPoint(A.V.add(B.V, &Overflow));
+    return Overflow;
+  }
+  static bool sub(const FixedPoint A, const FixedPoint B, unsigned Bits,
+                  FixedPoint *R) {
+    return true;
+  }
+  static bool mul(const FixedPoint A, const FixedPoint B, unsigned Bits,
+                  FixedPoint *R) {
+    return true;
+  }
+  static bool div(const FixedPoint A, const FixedPoint B, unsigned Bits,
+                  FixedPoint *R) {
+    return true;
+  }
+  static bool increment(const FixedPoint &A, FixedPoint *R) { return true; }
+  static bool decrement(const FixedPoint &A, FixedPoint *R) { return true; }
 };
 
 inline FixedPoint getSwappedBytes(FixedPoint F) { return F; }

clang/lib/AST/ByteCode/Opcodes.td

@@ -98,7 +98,7 @@ def FloatTypeClass : TypeClass {
 }
 
 def AluTypeClass : TypeClass {
-  let Types = !listconcat(IntegerTypeClass.Types, [Bool]);
+  let Types = !listconcat(IntegerTypeClass.Types, [Bool], [FixedPoint]);
 }
 
 def PtrTypeClass : TypeClass {
@@ -110,7 +110,7 @@ def NonPtrTypeClass : TypeClass {
 }
 
 def AllTypeClass : TypeClass {
-  let Types = !listconcat(AluTypeClass.Types, PtrTypeClass.Types, FloatTypeClass.Types, [FixedPoint]);
+  let Types = !listconcat(AluTypeClass.Types, PtrTypeClass.Types, FloatTypeClass.Types);
 }
 
 def ComparableTypeClass : TypeClass {

clang/test/AST/ByteCode/fixed-point.cpp

@@ -35,3 +35,15 @@ namespace FloatToFixedPointCast {
   constexpr float sf2f = sf2;
   static_assert(sf2f == 0.5);
 }
+
+namespace BinOps {
+  constexpr _Accum A = 13;
+  static_assert(A + 1 == 14.0k);
+  static_assert(1 + A == 14.0k);
+  static_assert((A + A) == 26);
+
+  /// FIXME: Conversion between fixed point semantics.
+  static_assert(A + 100000 == 14.0k); // expected-error {{static assertion failed}} \
+                                      // ref-error {{is not an integral constant expression}} \
+                                      // ref-note {{is outside the range of representable values}}
+}