[clang] Fix unexpected -Wconstant-logical-operand in C23 (llvm#80724)

C23 has `bool`, but logical operators still return int. Check that
we're not in C to avoid false-positive -Wconstant-logical-operand.

Fixes llvm#64356

Author: Fznamznon

clang/docs/ReleaseNotes.rst

@@ -164,6 +164,10 @@ Bug Fixes in This Version
 - Clang now accepts qualified partial/explicit specializations of variable templates that
   are not nominable in the lookup context of the specialization.
 
+- Clang now doesn't produce false-positive warning `-Wconstant-logical-operand`
+  for logical operators in C23.
+  Fixes (`#64356 <https://github.com/llvm/llvm-project/issues/64356>`_).
+
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

clang/lib/Sema/SemaExpr.cpp

@@ -14073,7 +14073,7 @@ inline QualType Sema::CheckLogicalOperands(ExprResult &LHS, ExprResult &RHS,
     Expr::EvalResult EVResult;
     if (RHS.get()->EvaluateAsInt(EVResult, Context)) {
       llvm::APSInt Result = EVResult.Val.getInt();
-      if ((getLangOpts().Bool && !RHS.get()->getType()->isBooleanType() &&
+      if ((getLangOpts().CPlusPlus && !RHS.get()->getType()->isBooleanType() &&
            !RHS.get()->getExprLoc().isMacroID()) ||
           (Result != 0 && Result != 1)) {
         Diag(Loc, diag::warn_logical_instead_of_bitwise)

clang/test/Sema/warn-int-in-bool-context.c

@@ -79,3 +79,14 @@ int test(int a, unsigned b, enum num n) {
   // Don't warn in macros.
   return SHIFT(1, a);
 }
+
+int GH64356(int arg) {
+  if ((arg == 1) && (1 == 1)) return 1;
+    return 0;
+
+  if ((64 > 32) && (32 < 64))
+    return 2;
+
+  if ((1 == 1) && (arg == 1)) return 1;
+    return 0;
+}