Remove warnings of constant operands of logical operators from template
instantiations. Upon instantiation of template, value-dependent parameters
are replaced by equivalent literals, so code like:
template<unsigned int A, unsigned int B> struct S {
int foo() {
int x = A && B;
}
}
will not warn on A && B on every instantiation. This will still warn on
other cases inside templates, which will be caught on checking the template
definition.
Patch attached and available at http://codereview.appspot.com/4650076/
Index: test/SemaCXX/expressions.cpp
===================================================================
--- test/SemaCXX/expressions.cpp (revision 135208)
+++ test/SemaCXX/expressions.cpp (working copy)
@@ -63,3 +63,25 @@
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}}
}
+
+template<unsigned int A, unsigned int B> struct S
+{
+ enum {
+ e1 = A && B,
+ e2 = A && 7 // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+ };
+
+ int foo() {
+ int x = A && B;
+ int y = B && 3; // expected-warning {{use of logical && with constant operand; switch to bitwise & or remove constant}}
+
+ return x + y;
+ }
+};
+
+void test3() {
+ S<5, 8> s1;
+ S<2, 7> s2;
+ (void)s1.foo();
+ (void)s2.foo();
+}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp (revision 135208)
+++ lib/Sema/SemaExpr.cpp (working copy)
@@ -6528,8 +6528,8 @@
// is a constant.
if (lex.get()->getType()->isIntegerType() && !lex.get()->getType()->isBooleanType() &&
rex.get()->getType()->isIntegerType() && !rex.get()->isValueDependent() &&
- // Don't warn in macros.
- !Loc.isMacroID()) {
+ // Don't warn in macros or template instantiations.
+ !Loc.isMacroID() && ActiveTemplateInstantiations.empty()) {
// 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.
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