[Fixed Point Arithmetic] Fixed Point Addition

This patch covers addition between fixed point types and other fixed point
types or integers, using the conversion rules described in 4.1.4 of N1169.

Usual arithmetic rules do not apply to binary operations when one of the
operands is a fixed point type, and the result of the operation must be
calculated with the full precision of the operands, so we should not perform
any casting to a common type.

This patch does not include constant expression evaluation for addition of
fixed point types. That will be addressed in another patch since I think this
one is already big enough.

Differential Revision: https://reviews.llvm.org/D53738

llvm-svn: 351364

1 files changed, 42 insertions, 1 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 21b6f36e9aa..ed203a331d5 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -10485,7 +10485,13 @@ unsigned char ASTContext::getFixedPointIBits(QualType Ty) const {
 }
 
 FixedPointSemantics ASTContext::getFixedPointSemantics(QualType Ty) const {
-  assert(Ty->isFixedPointType());
+  assert(Ty->isFixedPointType() ||
+         Ty->isIntegerType() && "Can only get the fixed point semantics for a "
+                                "fixed point or integer type.");
+  if (Ty->isIntegerType())
+    return FixedPointSemantics::GetIntegerSemantics(getIntWidth(Ty),
+                                                    Ty->isSignedIntegerType());
+
   bool isSigned = Ty->isSignedFixedPointType();
   return FixedPointSemantics(
       static_cast<unsigned>(getTypeSize(Ty)), getFixedPointScale(Ty), isSigned,
@@ -10502,3 +10508,38 @@ APFixedPoint ASTContext::getFixedPointMin(QualType Ty) const {
   assert(Ty->isFixedPointType());
   return APFixedPoint::getMin(getFixedPointSemantics(Ty));
 }
+
+QualType ASTContext::getCorrespondingSignedFixedPointType(QualType Ty) const {
+  assert(Ty->isUnsignedFixedPointType() &&
+         "Expected unsigned fixed point type");
+  const auto *BTy = Ty->getAs<BuiltinType>();
+
+  switch (BTy->getKind()) {
+  case BuiltinType::UShortAccum:
+    return ShortAccumTy;
+  case BuiltinType::UAccum:
+    return AccumTy;
+  case BuiltinType::ULongAccum:
+    return LongAccumTy;
+  case BuiltinType::SatUShortAccum:
+    return SatShortAccumTy;
+  case BuiltinType::SatUAccum:
+    return SatAccumTy;
+  case BuiltinType::SatULongAccum:
+    return SatLongAccumTy;
+  case BuiltinType::UShortFract:
+    return ShortFractTy;
+  case BuiltinType::UFract:
+    return FractTy;
+  case BuiltinType::ULongFract:
+    return LongFractTy;
+  case BuiltinType::SatUShortFract:
+    return SatShortFractTy;
+  case BuiltinType::SatUFract:
+    return SatFractTy;
+  case BuiltinType::SatULongFract:
+    return SatLongFractTy;
+  default:
+    llvm_unreachable("Unexpected unsigned fixed point type");
+  }
+}