fix unnecessary warning when using bitand with boolean operators (#81976)

This pull request fixes #77601 where using the `bitand` operator with
boolean operands should not trigger the warning, as it would indicate an
intentional use of bitwise AND rather than a typo or error.

Fixes #77601

Author: 11happy

clang/docs/ReleaseNotes.rst

@@ -250,6 +250,10 @@ Improvements to Clang's diagnostics
   such as attempting to call ``free`` on an unallocated object. Fixes
   `#79443 <https://github.com/llvm/llvm-project/issues/79443>`_.
 
+- Clang no longer warns when the ``bitand`` operator is used with boolean
+  operands, distinguishing it from potential typographical errors or unintended
+  bitwise operations. Fixes #GH77601.
+
 Improvements to Clang's time-trace
 ----------------------------------
 

clang/lib/Sema/SemaChecking.cpp

@@ -16605,12 +16605,26 @@ static void AnalyzeImplicitConversions(
         BO->getRHS()->isKnownToHaveBooleanValue() &&
         BO->getLHS()->HasSideEffects(S.Context) &&
         BO->getRHS()->HasSideEffects(S.Context)) {
-      S.Diag(BO->getBeginLoc(), diag::warn_bitwise_instead_of_logical)
-          << (BO->getOpcode() == BO_And ? "&" : "|") << OrigE->getSourceRange()
-          << FixItHint::CreateReplacement(
-                 BO->getOperatorLoc(),
-                 (BO->getOpcode() == BO_And ? "&&" : "||"));
-      S.Diag(BO->getBeginLoc(), diag::note_cast_operand_to_int);
+      SourceManager &SM = S.getSourceManager();
+      const LangOptions &LO = S.getLangOpts();
+      SourceLocation BLoc = BO->getOperatorLoc();
+      SourceLocation ELoc = Lexer::getLocForEndOfToken(BLoc, 0, SM, LO);
+      StringRef SR = clang::Lexer::getSourceText(
+          clang::CharSourceRange::getTokenRange(BLoc, ELoc), SM, LO);
+      // To reduce false positives, only issue the diagnostic if the operator
+      // is explicitly spelled as a punctuator. This suppresses the diagnostic
+      // when using 'bitand' or 'bitor' either as keywords in C++ or as macros
+      // in C, along with other macro spellings the user might invent.
+      if (SR.str() == "&" || SR.str() == "|") {
+
+        S.Diag(BO->getBeginLoc(), diag::warn_bitwise_instead_of_logical)
+            << (BO->getOpcode() == BO_And ? "&" : "|")
+            << OrigE->getSourceRange()
+            << FixItHint::CreateReplacement(
+                   BO->getOperatorLoc(),
+                   (BO->getOpcode() == BO_And ? "&&" : "||"));
+        S.Diag(BO->getBeginLoc(), diag::note_cast_operand_to_int);
+      }
     }
 
   // For conditional operators, we analyze the arguments as if they

clang/test/Sema/warn-bitwise-and-bool.c

@@ -19,6 +19,8 @@ boolean baz(void) __attribute__((const));
 void sink(boolean);
 
 #define FOO foo()
+#define MY_AND &
+#define My_BITAND bitand
 
 void test(boolean a, boolean b, int *p, volatile int *q, int i) {
   b = a & b;
@@ -44,9 +46,12 @@ void test(boolean a, boolean b, int *p, volatile int *q, int i) {
   b = b & foo();
   b = bar() & (i > 4);
   b = (i == 7) & foo();
+  b = b MY_AND foo();     // OK, no warning expected
+
 #ifdef __cplusplus
-  b = foo() bitand bar(); // expected-warning {{use of bitwise '&' with boolean operands}}
-                          // expected-note@-1 {{cast one or both operands to int to silence this warning}}
+  b = foo() bitand bar(); // Ok, no warning expected
+  b = foo() My_BITAND bar(); // Ok, no warning expected
+                          
 #endif
 
   if (foo() & bar())      // expected-warning {{use of bitwise '&' with boolean operands}}
@@ -60,4 +65,5 @@ void test(boolean a, boolean b, int *p, volatile int *q, int i) {
 
   int n = i + 10;
   b = (n & (n - 1));
+
 }

clang/test/Sema/warn-bitwise-or-bool.c

@@ -19,6 +19,8 @@ boolean baz(void) __attribute__((const));
 void sink(boolean);
 
 #define FOO foo()
+#define MY_OR |
+#define My_BITOR bitor
 
 void test(boolean a, boolean b, int *p, volatile int *q, int i) {
   b = a | b;
@@ -44,9 +46,11 @@ void test(boolean a, boolean b, int *p, volatile int *q, int i) {
   b = b | foo();
   b = bar() | (i > 4);
   b = (i == 7) | foo();
+  b = b MY_OR foo();     // OK, no warning expected
 #ifdef __cplusplus
-  b = foo() bitor bar();  // expected-warning {{use of bitwise '|' with boolean operands}}
-                          // expected-note@-1 {{cast one or both operands to int to silence this warning}}
+  b = foo() bitor bar();  //Ok, no warning expected
+  b = foo() My_BITOR bar(); // Ok, no warning expected
+                          
 #endif
 
   if (foo() | bar())      // expected-warning {{use of bitwise '|' with boolean operands}}