On Thu, May 26, 2011 at 3:18 AM, Chandler Carruth <[email protected]>wrote:
> On Fri, May 6, 2011 at 1:38 PM, Richard Trieu <[email protected]> wrote:
>
>> The old warning that checked for logical operators with constants did not
>> treat 1 and 0 as it would for other constants. Changed the warning so that
>> if a bool type exists, 1 and 0 will trigger the warning.
>>
>
> Is there a PR for this? It'd be good to have more motivating examples in
> the description or something... But you do have one in the Code Review
> description I see.
>
>
>> Patch is attached and available through Code Review:
>> http://codereview.appspot.com/4444068/
>>
>
> Some minor comments left on the patch here.
>
Made the changes that Chandler suggested in Code Review. Anyone else have
any comments on this patch?
Index: test/Sema/exprs.c
===================================================================
--- test/Sema/exprs.c (revision 130248)
+++ test/Sema/exprs.c (working copy)
@@ -189,6 +189,24 @@
// no warning, this is an idiom for "true" in old C style.
return x && (signed char)1;
+
+ return x || 0;
+ return x || 1;
+ return x || -1; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || 5; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x && 0;
+ return x && 1;
+ return x && -1; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && 5; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x || (0);
+ return x || (1);
+ return x || (-1); // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || (5); // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x && (0);
+ return x && (1);
+ return x && (-1); // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && (5); // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+
}
struct Test21; // expected-note 2 {{forward declaration}}
Index: test/CodeGenCXX/static-init-2.cpp
===================================================================
--- test/CodeGenCXX/static-init-2.cpp (revision 130248)
+++ test/CodeGenCXX/static-init-2.cpp (working copy)
@@ -3,4 +3,4 @@
// Make sure we don't crash generating y; its value is constant, but the
// initializer has side effects, so EmitConstantExpr should fail.
int x();
-int y = x() && 0;
+int y = x() & 0;
Index: test/SemaCXX/expressions.cpp
===================================================================
--- test/SemaCXX/expressions.cpp (revision 130248)
+++ test/SemaCXX/expressions.cpp (working copy)
@@ -32,3 +32,34 @@
bar(x += E_zero); // expected-error {{incompatible type}}
}
}
+
+int test2(int x) {
+ return x && 4; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+
+ return x && sizeof(int) == 4; // no warning, RHS is logical op.
+ return x && true;
+ return x && false;
+ return x || true;
+ return x || false;
+
+ return x && (unsigned)0; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+
+ return x || (unsigned)1; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+
+ return x || 0; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || 1; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || -1; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || 5; // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x && 0; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && 1; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && -1; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && 5; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x || (0); // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || (1); // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || (-1); // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x || (5); // expected-warning {{use of logical || with constant operand; switch to bitwise | or remove constant}}
+ return x && (0); // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && (1); // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && (-1); // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ return x && (5); // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+}
Index: test/SemaCXX/switch.cpp
===================================================================
--- test/SemaCXX/switch.cpp (revision 130248)
+++ test/SemaCXX/switch.cpp (working copy)
@@ -8,7 +8,7 @@
}
int n = 3;
- switch (n && 1) { // expected-warning {{bool}}
+ switch (n && true) { // expected-warning {{bool}}
case 1:
break;
}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp (revision 130248)
+++ lib/Sema/SemaExpr.cpp (working copy)
@@ -7737,13 +7737,15 @@
// If the RHS can be constant folded, and if it constant folds to something
// that isn't 0 or 1 (which indicate a potential logical operation that
// happened to fold to true/false) then warn.
+ // Parens on the RHS are ignored.
Expr::EvalResult Result;
- if (rex.get()->Evaluate(Result, Context) && !Result.HasSideEffects &&
- Result.Val.getInt() != 0 && Result.Val.getInt() != 1) {
- Diag(Loc, diag::warn_logical_instead_of_bitwise)
- << rex.get()->getSourceRange()
- << (Opc == BO_LAnd ? "&&" : "||")
- << (Opc == BO_LAnd ? "&" : "|");
+ if (rex.get()->Evaluate(Result, Context) && !Result.HasSideEffects)
+ if ((getLangOptions().Bool && !rex.get()->getType()->isBooleanType()) ||
+ (Result.Val.getInt() != 0 && Result.Val.getInt() != 1)) {
+ Diag(Loc, diag::warn_logical_instead_of_bitwise)
+ << rex.get()->getSourceRange()
+ << (Opc == BO_LAnd ? "&&" : "||")
+ << (Opc == BO_LAnd ? "&" : "|");
}
}
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