[Fixed Point Arithmetic] Fixed Point and Integer Conversions

This patch includes the necessary code for converting between a fixed point type and integer.
This also includes constant expression evaluation for conversions with these types.

Differential Revision: https://reviews.llvm.org/D56900

llvm-svn: 355462

2 files changed, 44 insertions, 7 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 5d9ae18267b..8dc9c7ffcdb 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -11018,10 +11018,9 @@ CheckImplicitConversion(Sema &S, Expr *E, QualType T, SourceLocation CC,
     return;
   }
 
+  // Valid casts involving fixed point types should be accounted for here.
   if (Source->isFixedPointType()) {
-    // TODO: Only CK_FixedPointCast is supported now. The other valid casts
-    // should be accounted for here.
-    if (Target->isFixedPointType()) {
+    if (Target->isUnsaturatedFixedPointType()) {
       Expr::EvalResult Result;
       if (E->EvaluateAsFixedPoint(Result, S.Context,
                                   Expr::SE_AllowSideEffects)) {
@@ -11037,6 +11036,46 @@ CheckImplicitConversion(Sema &S, Expr *E, QualType T, SourceLocation CC,
           return;
         }
       }
+    } else if (Target->isIntegerType()) {
+      Expr::EvalResult Result;
+      if (E->EvaluateAsFixedPoint(Result, S.Context,
+                                  Expr::SE_AllowSideEffects)) {
+        APFixedPoint FXResult = Result.Val.getFixedPoint();
+
+        bool Overflowed;
+        llvm::APSInt IntResult = FXResult.convertToInt(
+            S.Context.getIntWidth(T),
+            Target->isSignedIntegerOrEnumerationType(), &Overflowed);
+
+        if (Overflowed) {
+          S.DiagRuntimeBehavior(E->getExprLoc(), E,
+                                S.PDiag(diag::warn_impcast_fixed_point_range)
+                                    << FXResult.toString() << T
+                                    << E->getSourceRange()
+                                    << clang::SourceRange(CC));
+          return;
+        }
+      }
+    }
+  } else if (Target->isUnsaturatedFixedPointType()) {
+    if (Source->isIntegerType()) {
+      Expr::EvalResult Result;
+      if (E->EvaluateAsInt(Result, S.Context, Expr::SE_AllowSideEffects)) {
+        llvm::APSInt Value = Result.Val.getInt();
+
+        bool Overflowed;
+        APFixedPoint IntResult = APFixedPoint::getFromIntValue(
+            Value, S.Context.getFixedPointSemantics(T), &Overflowed);
+
+        if (Overflowed) {
+          S.DiagRuntimeBehavior(E->getExprLoc(), E,
+                                S.PDiag(diag::warn_impcast_fixed_point_range)
+                                    << Value.toString(/*radix=*/10) << T
+                                    << E->getSourceRange()
+                                    << clang::SourceRange(CC));
+          return;
+        }
+      }
     }
   }
 
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 19ed62d1fe6..187d8e2fddd 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6152,6 +6152,7 @@ CastKind Sema::PrepareScalarCast(ExprResult &Src, QualType DestTy) {
     case Type::STK_Bool:
       return CK_FixedPointToBoolean;
     case Type::STK_Integral:
+      return CK_FixedPointToIntegral;
     case Type::STK_Floating:
     case Type::STK_IntegralComplex:
     case Type::STK_FloatingComplex:
@@ -6196,10 +6197,7 @@ CastKind Sema::PrepareScalarCast(ExprResult &Src, QualType DestTy) {
     case Type::STK_MemberPointer:
       llvm_unreachable("member pointer type in C");
     case Type::STK_FixedPoint:
-      Diag(Src.get()->getExprLoc(),
-           diag::err_unimplemented_conversion_with_fixed_point_type)
-          << SrcTy;
-      return CK_IntegralCast;
+      return CK_IntegralToFixedPoint;
     }
     llvm_unreachable("Should have returned before this");