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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:

Browse Source 
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.

llvm-svn: 135222
This commit is contained in:
Richard Trieu
2011-07-15 00:00:51 +00:00
parent e625325d9f
commit cfe3926ae9
2 changed files with 24 additions and 2 deletions
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4
clang/lib/Sema/SemaExpr.cpp
View File

@@ -6528,8 +6528,8 @@ inline QualType Sema::CheckLogicalOperands( // C99 6.5.[13,14]
// 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.

22
clang/test/SemaCXX/expressions.cpp
View File

@@ -63,3 +63,25 @@ int test2(int x) {
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();
}