Silence the -Wbitfield-constant-conversion warning for when -1 or other
negative values are assigned to unsigned bitfields, provided that the bitfield
is wider than the minimum number of bits needed to encode the negative value.
llvm-svn: 277796
unsigned OriginalWidth = Value.getBitWidth();
unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
+ if (Value.isSigned() && Value.isNegative())
+ if (UnaryOperator *UO = dyn_cast<UnaryOperator>(OriginalInit))
+ if (UO->getOpcode() == UO_Minus)
+ if (isa<IntegerLiteral>(UO->getSubExpr()))
+ OriginalWidth = Value.getMinSignedBits();
+
if (OriginalWidth <= FieldWidth)
return false;
struct Test5 { unsigned n : 2; } t5;
// Bitfield is unsigned
-struct Test5 sometest5 = {-1}; // expected-warning {{implicit truncation from 'int' to bitfield changes value from -1 to 3}}
+struct Test5 sometest5 = {-1};
typedef __typeof__(+t5.n) Signed; // ... but promotes to signed.
typedef __typeof__(t5.n + 0) Signed; // Arithmetic promotes.
char array_init[] = { 255, 127, 128, 129, 0 };
}
+
+void test10() {
+ struct S {
+ unsigned a : 4;
+ } s;
+ s.a = -1;
+ s.a = 15;
+ s.a = -8;
+
+ s.a = -9; // expected-warning{{implicit truncation from 'int' to bitfield changes value from -9 to 7}}
+ s.a = 16; // expected-warning{{implicit truncation from 'int' to bitfield changes value from 16 to 0}}
+}