Revert "[Clang] Fix -Wconstant-logical-operand when LHS is a constant"

xgupta · tru · commit a93ca35a4494 · 2023-08-09T08:58:21.000+02:00
This reverts commit dfdfd30. An issue is reported for wrong warning, this has to be reconsidered. Differential Revision: https://reviews.llvm.org/D157352
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
@@ -12694,8 +12694,6 @@ class Sema final {
   QualType CheckBitwiseOperands( // C99 6.5.[10...12]
       ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
       BinaryOperatorKind Opc);
-  void diagnoseLogicalInsteadOfBitwise(Expr *Op1, Expr *Op2, SourceLocation Loc,
-                                       BinaryOperatorKind Opc);
   QualType CheckLogicalOperands( // C99 6.5.[13,14]
     ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
     BinaryOperatorKind Opc);
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
@@ -13880,56 +13880,6 @@ inline QualType Sema::CheckBitwiseOperands(ExprResult &LHS, ExprResult &RHS,
   return InvalidOperands(Loc, LHS, RHS);
 }
 
-// Diagnose cases where the user write a logical and/or but probably meant a
-// bitwise one.  We do this when one of the operands is a non-bool integer and
-// the other is a constant.
-void Sema::diagnoseLogicalInsteadOfBitwise(Expr *Op1, Expr *Op2,
-                                           SourceLocation Loc,
-                                           BinaryOperatorKind Opc) {
-  if (Op1->getType()->isIntegerType() && !Op1->getType()->isBooleanType() &&
-      Op2->getType()->isIntegerType() && !Op2->isValueDependent() &&
-      // Don't warn in macros or template instantiations.
-      !Loc.isMacroID() && !inTemplateInstantiation() &&
-      !Op2->getExprLoc().isMacroID() &&
-      !Op1->getExprLoc().isMacroID()) {
-    bool IsOp1InMacro = Op1->getExprLoc().isMacroID();
-    bool IsOp2InMacro = Op2->getExprLoc().isMacroID();
-
-    // Exclude the specific expression from triggering the warning.
-    if (!(IsOp1InMacro && IsOp2InMacro && Op1->getSourceRange() == Op2->getSourceRange())) {
-    // 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.
-    // 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 EVResult;
-    if (Op2->EvaluateAsInt(EVResult, Context)) {
-      llvm::APSInt Result = EVResult.Val.getInt();
-      if ((getLangOpts().Bool && !Op2->getType()->isBooleanType() &&
-           !Op2->getExprLoc().isMacroID()) ||
-          (Result != 0 && Result != 1)) {
-        Diag(Loc, diag::warn_logical_instead_of_bitwise)
-            << Op2->getSourceRange() << (Opc == BO_LAnd ? "&&" : "||");
-        // Suggest replacing the logical operator with the bitwise version
-        Diag(Loc, diag::note_logical_instead_of_bitwise_change_operator)
-            << (Opc == BO_LAnd ? "&" : "|")
-            << FixItHint::CreateReplacement(
-                   SourceRange(Loc, getLocForEndOfToken(Loc)),
-                   Opc == BO_LAnd ? "&" : "|");
-        if (Opc == BO_LAnd)
-          // Suggest replacing "Foo() && kNonZero" with "Foo()"
-          Diag(Loc, diag::note_logical_instead_of_bitwise_remove_constant)
-              << FixItHint::CreateRemoval(SourceRange(
-                     getLocForEndOfToken(Op1->getEndLoc()), Op2->getEndLoc()));
-      }
-    }
-  }
-      }
-}
-
 // C99 6.5.[13,14]
 inline QualType Sema::CheckLogicalOperands(ExprResult &LHS, ExprResult &RHS,
                                            SourceLocation Loc,
@@ -13948,6 +13898,9 @@ inline QualType Sema::CheckLogicalOperands(ExprResult &LHS, ExprResult &RHS,
     }
   }
 
+  if (EnumConstantInBoolContext)
+    Diag(Loc, diag::warn_enum_constant_in_bool_context);
+
   // WebAssembly tables can't be used with logical operators.
   QualType LHSTy = LHS.get()->getType();
   QualType RHSTy = RHS.get()->getType();
@@ -13958,14 +13911,40 @@ inline QualType Sema::CheckLogicalOperands(ExprResult &LHS, ExprResult &RHS,
     return InvalidOperands(Loc, LHS, RHS);
   }
 
-  if (EnumConstantInBoolContext) {
-    // Warn when converting the enum constant to a boolean
-    Diag(Loc, diag::warn_enum_constant_in_bool_context);
-  } else {
-    // Diagnose cases where the user write a logical and/or but probably meant a
-    // bitwise one.
-    diagnoseLogicalInsteadOfBitwise(LHS.get(), RHS.get(), Loc, Opc);
-    diagnoseLogicalInsteadOfBitwise(RHS.get(), LHS.get(), Loc, Opc);
+  // Diagnose cases where the user write a logical and/or but probably meant a
+  // bitwise one.  We do this when the LHS is a non-bool integer and the RHS
+  // is a constant.
+  if (!EnumConstantInBoolContext && LHS.get()->getType()->isIntegerType() &&
+      !LHS.get()->getType()->isBooleanType() &&
+      RHS.get()->getType()->isIntegerType() && !RHS.get()->isValueDependent() &&
+      // Don't warn in macros or template instantiations.
+      !Loc.isMacroID() && !inTemplateInstantiation()) {
+    // 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 EVResult;
+    if (RHS.get()->EvaluateAsInt(EVResult, Context)) {
+      llvm::APSInt Result = EVResult.Val.getInt();
+      if ((getLangOpts().Bool && !RHS.get()->getType()->isBooleanType() &&
+           !RHS.get()->getExprLoc().isMacroID()) ||
+          (Result != 0 && Result != 1)) {
+        Diag(Loc, diag::warn_logical_instead_of_bitwise)
+            << RHS.get()->getSourceRange() << (Opc == BO_LAnd ? "&&" : "||");
+        // Suggest replacing the logical operator with the bitwise version
+        Diag(Loc, diag::note_logical_instead_of_bitwise_change_operator)
+            << (Opc == BO_LAnd ? "&" : "|")
+            << FixItHint::CreateReplacement(
+                   SourceRange(Loc, getLocForEndOfToken(Loc)),
+                   Opc == BO_LAnd ? "&" : "|");
+        if (Opc == BO_LAnd)
+          // Suggest replacing "Foo() && kNonZero" with "Foo()"
+          Diag(Loc, diag::note_logical_instead_of_bitwise_remove_constant)
+              << FixItHint::CreateRemoval(
+                     SourceRange(getLocForEndOfToken(LHS.get()->getEndLoc()),
+                                 RHS.get()->getEndLoc()));
+      }
+    }
   }
 
   if (!Context.getLangOpts().CPlusPlus) {
diff --git a/clang/test/C/drs/dr4xx.c b/clang/test/C/drs/dr4xx.c
@@ -308,9 +308,7 @@ void dr489(void) {
   case (int){ 2 }: break;   /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}
                                c89only-warning {{compound literals are a C99-specific feature}}
                              */
-  case 12 || main(): break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}
-                               expected-warning {{use of logical '||' with constant operand}} \
-                               expected-note {{use '|' for a bitwise operation}} */
+  case 12 || main(): break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}} */
   }
 }
 
diff --git a/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp b/clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp
@@ -72,15 +72,9 @@ constexpr S InitList3(int a) { return a ? S{ a, a } : S{ a, ng }; }; // ok
 
 constexpr int LogicalAnd1(int n) { return n && (throw, 0); } // ok
 constexpr int LogicalAnd2(int n) { return 1 && (throw, 0); } // expected-error {{never produces}} expected-note {{subexpression}}
-                                                             // expected-warning@-1 {{use of logical '&&' with constant operand}}
-                                                             // expected-note@-2 {{use '&' for a bitwise operation}}
-                                                             // expected-note@-3 {{remove constant to silence this warning}}
 
 constexpr int LogicalOr1(int n) { return n || (throw, 0); } // ok
 constexpr int LogicalOr2(int n) { return 0 || (throw, 0); } // expected-error {{never produces}} expected-note {{subexpression}}
-                                                            // expected-warning@-1 {{use of logical '||' with constant operand}}
-                                                            // expected-note@-2 {{use '|' for a bitwise operation}}
-
 
 constexpr int Conditional1(bool b, int n) { return b ? n : ng; } // ok
 constexpr int Conditional2(bool b, int n) { return b ? n * ng : n + ng; } // expected-error {{never produces}} expected-note {{both arms of conditional operator are unable to produce a constant expression}}
diff --git a/clang/test/Parser/cxx2a-concept-declaration.cpp b/clang/test/Parser/cxx2a-concept-declaration.cpp
@@ -79,11 +79,6 @@ template<typename T> concept C16 = true && (0 && 0); // expected-error {{atomic
 // expected-warning@-1{{use of logical '&&' with constant operand}}
 // expected-note@-2{{use '&' for a bitwise operation}}
 // expected-note@-3{{remove constant to silence this warning}}
-// expected-warning@-4{{use of logical '&&' with constant operand}}
-// expected-note@-5{{use '&' for a bitwise operation}}
-// expected-note@-6{{remove constant to silence this warning}}
-
-
 template<typename T> concept C17 = T{};
 static_assert(!C17<bool>);
 template<typename T> concept C18 = (bool&&)true;
diff --git a/clang/test/Sema/exprs.c b/clang/test/Sema/exprs.c
@@ -212,10 +212,6 @@ int test20(int x) {
                  // expected-note {{use '&' for a bitwise operation}} \
                  // expected-note {{remove constant to silence this warning}}
 
-  return 4 && x; // expected-warning {{use of logical '&&' with constant operand}} \
-                 // expected-note {{use '&' for a bitwise operation}} \
-                 // expected-note {{remove constant to silence this warning}}
-
   return x && sizeof(int) == 4;  // no warning, RHS is logical op.
   
   // no warning, this is an idiom for "true" in old C style.
@@ -227,9 +223,6 @@ int test20(int x) {
                   // expected-note {{use '|' for a bitwise operation}}
   return x || 5; // expected-warning {{use of logical '||' with constant operand}} \
                  // expected-note {{use '|' for a bitwise operation}}
-  return 5 || x; // expected-warning {{use of logical '||' with constant operand}} \
-                 // expected-note {{use '|' for a bitwise operation}}
-
   return x && 0;
   return x && 1;
   return x && -1; // expected-warning {{use of logical '&&' with constant operand}} \
diff --git a/clang/test/SemaCXX/expressions.cpp b/clang/test/SemaCXX/expressions.cpp
@@ -44,9 +44,6 @@ int test2(int x) {
   return x && 4; // expected-warning {{use of logical '&&' with constant operand}} \
                    // expected-note {{use '&' for a bitwise operation}} \
                    // expected-note {{remove constant to silence this warning}}
-  return 4 && x; // expected-warning {{use of logical '&&' with constant operand}} \
-                   // expected-note {{use '&' for a bitwise operation}} \
-                   // expected-note {{remove constant to silence this warning}}
 
   return x && sizeof(int) == 4;  // no warning, RHS is logical op.
   return x && true;
@@ -69,8 +66,6 @@ int test2(int x) {
                    // expected-note {{use '|' for a bitwise operation}}
   return x || 5; // expected-warning {{use of logical '||' with constant operand}} \
                    // expected-note {{use '|' for a bitwise operation}}
-  return 5 || x; // expected-warning {{use of logical '||' with constant operand}} \
-                   // expected-note {{use '|' for a bitwise operation}}
   return x && 0; // expected-warning {{use of logical '&&' with constant operand}} \
                    // expected-note {{use '&' for a bitwise operation}} \
                    // expected-note {{remove constant to silence this warning}}
@@ -144,5 +139,6 @@ void test4() {
   bool r1 = X || Y;
 
   #define Y2 2
-  bool r2 = X || Y2;
+  bool r2 = X || Y2; // expected-warning {{use of logical '||' with constant operand}} \
+                     // expected-note {{use '|' for a bitwise operation}}
 }
diff --git a/clang/test/SemaCXX/warn-unsequenced.cpp b/clang/test/SemaCXX/warn-unsequenced.cpp
@@ -76,37 +76,15 @@ void test() {
 
   (xs[2] && (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
                           // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
-
-  (0 && (a = 0)) + a; // cxx11-warning {{use of logical '&&' with constant operand}}
-                      // cxx11-note@-1 {{use '&' for a bitwise operation}}
-                      // cxx11-note@-2 {{remove constant to silence this warning}}
-                      // cxx17-warning@-3 {{use of logical '&&' with constant operand}}
-                      // cxx17-note@-4 {{use '&' for a bitwise operation}}
-                      // cxx17-note@-5 {{remove constant to silence this warning}}
-
+  (0 && (a = 0)) + a; // ok
   (1 && (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
                       // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
-                      // cxx11-warning@-2 {{use of logical '&&' with constant operand}}
-                      // cxx11-note@-3 {{use '&' for a bitwise operation}}
-                      // cxx11-note@-4 {{remove constant to silence this warning}}
-                      // cxx17-warning@-5 {{use of logical '&&' with constant operand}}
-                      // cxx17-note@-6 {{use '&' for a bitwise operation}}
-                      // cxx17-note@-7 {{remove constant to silence this warning}}
-
 
   (xs[3] || (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
                           // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
   (0 || (a = 0)) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
                       // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
-                      // cxx11-warning@-2 {{use of logical '||' with constant operand}}
-                      // cxx11-note@-3 {{use '|' for a bitwise operation}}
-                      // cxx17-warning@-4 {{use of logical '||' with constant operand}}
-                      // cxx17-note@-5 {{use '|' for a bitwise operation}}
-  (1 || (a = 0)) + a; // cxx11-warning {{use of logical '||' with constant operand}}
-                      // cxx11-note@-1 {{use '|' for a bitwise operation}}
-                      // cxx17-warning@-2 {{use of logical '||' with constant operand}}
-                      // cxx17-note@-3 {{use '|' for a bitwise operation}}
-
+  (1 || (a = 0)) + a; // ok
 
   (xs[4] ? a : ++a) + a; // cxx11-warning {{unsequenced modification and access to 'a'}}
                          // cxx17-warning@-1 {{unsequenced modification and access to 'a'}}
diff --git a/clang/test/SemaTemplate/dependent-expr.cpp b/clang/test/SemaTemplate/dependent-expr.cpp
@@ -43,9 +43,7 @@ namespace PR7198 {
 
 namespace PR7724 {
   template<typename OT> int myMethod()
-  { return 2 && sizeof(OT); } // expected-warning {{use of logical '&&' with constant operand}} \
-                              // expected-note {{use '&' for a bitwise operation}} \
-                              // expected-note {{remove constant to silence this warning}}
+  { return 2 && sizeof(OT); }
 }
 
 namespace test4 {

Original file line number	Diff line number	Diff line change
`@@ -308,9 +308,7 @@ void dr489(void) {`
`308`	`308`	`case (int){ 2 }: break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}`
`309`	`309`	`c89only-warning {{compound literals are a C99-specific feature}}`
`310`	`310`	`*/`
`311`		`- case 12 \|\| main(): break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}`
`312`		`- expected-warning {{use of logical '\|\|' with constant operand}} \`
`313`		`- expected-note {{use '\|' for a bitwise operation}} */`
	`311`	`+ case 12 \|\| main(): break; /* expected-warning {{expression is not an integer constant expression; folding it to a constant is a GNU extension}} */`
`314`	`312`	`}`
`315`	`313`	`}`
`316`	`314`
Original file line number	Diff line number	Diff line change
`@@ -43,9 +43,7 @@ namespace PR7198 {`
`43`	`43`
`44`	`44`	`namespace PR7724 {`
`45`	`45`	`template<typename OT> int myMethod()`
`46`		`- { return 2 && sizeof(OT); } // expected-warning {{use of logical '&&' with constant operand}} \`
`47`		`- // expected-note {{use '&' for a bitwise operation}} \`
`48`		`- // expected-note {{remove constant to silence this warning}}`
	`46`	`+ { return 2 && sizeof(OT); }`
`49`	`47`	`}`
`50`	`48`
`51`	`49`	`namespace test4 {`