Author: avt77
Date: Thu Mar 15 03:03:35 2018
New Revision: 327618
URL: http://llvm.org/viewvc/llvm-project?rev=327618&view=rev
Log:
More warnings when double truncation to float: compound assignment is supported
now.
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/test/Sema/conversion.c
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=327618&r1=327617&r2=327618&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Mar 15 03:03:35
2018
@@ -3093,6 +3093,9 @@ def err_impcast_complex_scalar : Error<
def warn_impcast_float_precision : Warning<
"implicit conversion loses floating-point precision: %0 to %1">,
InGroup<Conversion>, DefaultIgnore;
+def warn_impcast_float_result_precision : Warning<
+ "implicit conversion when assigning computation result loses floating-point
precision: %0 to %1">,
+ InGroup<Conversion>, DefaultIgnore;
def warn_impcast_double_promotion : Warning<
"implicit conversion increases floating-point precision: %0 to %1">,
InGroup<DoublePromotion>, DefaultIgnore;
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=327618&r1=327617&r2=327618&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Thu Mar 15 03:03:35 2018
@@ -9183,6 +9183,32 @@ static void DiagnoseImpCast(Sema &S, Exp
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 @@ CheckImplicitConversion(Sema &S, Expr *E
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 @@ static void AnalyzeImplicitConversions(S
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 @@ static void AnalyzeImplicitConversions(S
// 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,
Modified: cfe/trunk/test/Sema/conversion.c
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/conversion.c?rev=327618&r1=327617&r2=327618&view=diff
==============================================================================
--- cfe/trunk/test/Sema/conversion.c (original)
+++ cfe/trunk/test/Sema/conversion.c Thu Mar 15 03:03:35 2018
@@ -436,10 +436,15 @@ float double2float_test1(double a) {
}
void double2float_test2(double a, float *b) {
- *b += a;
+ *b += a; // expected-warning {{implicit conversion when assigning
computation result loses floating-point precision: 'double' to 'float'}}
}
float sinf (float x);
double double2float_test3(double a) {
return sinf(a); // expected-warning {{implicit conversion loses
floating-point precision: 'double' to 'float'}}
}
+
+float double2float_test4(double a, float b) {
+ b -= a; // expected-warning {{implicit conversion when assigning computation
result loses floating-point precision: 'double' to 'float'}}
+ return b;
+}
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