[PATCH] D33563: Track whether a unary operation can overflow

[Eli Friedman via Phabricator via cfe-commits]

efriedma added inline comments.


================
Comment at: include/clang/AST/Expr.h:1728
+  UnaryOperator(Expr *input, Opcode opc, QualType type, ExprValueKind VK,
+                ExprObjectKind OK, SourceLocation l, bool CanOverflow = false)
+      : Expr(UnaryOperatorClass, type, VK, OK,
----------------
Is the default argument necessary here?  Better to avoid when possible.


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Comment at: lib/Sema/SemaExpr.cpp:12212
   case UO_Minus:
+    CanOverflow = isOverflowingIntegerType(Context, Input.get()->getType());
     Input = UsualUnaryConversions(Input.get());
----------------
UO_Plus can't overflow.


================
Comment at: test/Misc/ast-dump-stmt.c:66
+  // CHECK:        ImplicitCastExpr
+  // CHECK:          DeclRefExpr{{.*}}'T2' 'int'
+}
----------------
What does it mean for bitwise complement to "overflow"?


https://reviews.llvm.org/D33563