More warnings when double truncation to float: compound assignment is supported now.
llvm-svn: 327618
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index e4bb7ea..a575def 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -9183,6 +9183,32 @@
DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
}
+/// Analyze the given compound assignment for the possible losing of
+/// floating-point precision.
+static void AnalyzeCompoundAssignment(Sema &S, BinaryOperator *E) {
+ assert(isa<CompoundAssignOperator>(E) &&
+ "Must be compound assignment operation");
+ // Recurse on the LHS and RHS in here
+ AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
+ AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
+
+ // Now check the outermost expression
+ const auto *ResultBT = E->getLHS()->getType()->getAs<BuiltinType>();
+ const auto *RBT = cast<CompoundAssignOperator>(E)
+ ->getComputationResultType()
+ ->getAs<BuiltinType>();
+
+ // If both source and target are floating points.
+ if (ResultBT && ResultBT->isFloatingPoint() && RBT && RBT->isFloatingPoint())
+ // Builtin FP kinds are ordered by increasing FP rank.
+ if (ResultBT->getKind() < RBT->getKind())
+ // We don't want to warn for system macro.
+ if (!S.SourceMgr.isInSystemMacro(E->getOperatorLoc()))
+ // warn about dropping FP rank.
+ DiagnoseImpCast(S, E->getRHS(), E->getLHS()->getType(),
+ E->getOperatorLoc(),
+ diag::warn_impcast_float_result_precision);
+}
/// Diagnose an implicit cast from a floating point value to an integer value.
static void DiagnoseFloatingImpCast(Sema &S, Expr *E, QualType T,
@@ -9550,7 +9576,7 @@
return;
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
}
-
+
// If the vector cast is cast between two vectors of the same size, it is
// a bitcast, not a conversion.
if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
@@ -9827,7 +9853,7 @@
if (E->isTypeDependent() || E->isValueDependent())
return;
-
+
// For conditional operators, we analyze the arguments as if they
// were being fed directly into the output.
if (isa<ConditionalOperator>(E)) {
@@ -9871,6 +9897,9 @@
// And with simple assignments.
if (BO->getOpcode() == BO_Assign)
return AnalyzeAssignment(S, BO);
+ // And with compound assignments.
+ if (BO->isAssignmentOp())
+ return AnalyzeCompoundAssignment(S, BO);
}
// These break the otherwise-useful invariant below. Fortunately,