r373614 - [Diagnostics] Bitwise negation of a boolean expr always evaluates to true; warn with -Wbool-operation

[David Bolvansky via cfe-commits]

Author: xbolva00
Date: Thu Oct  3 08:17:59 2019
New Revision: 373614

URL: http://llvm.org/viewvc/llvm-project?rev=373614&view=rev
Log:
[Diagnostics] Bitwise negation of a boolean expr always evaluates to true; warn with -Wbool-operation

Requested here:
http://lists.llvm.org/pipermail/cfe-dev/2019-October/063452.html


Added:
    cfe/trunk/test/Sema/warn-bitwise-negation-bool.c
Modified:
    cfe/trunk/lib/Sema/SemaExpr.cpp

Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=373614&r1=373613&r2=373614&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Thu Oct  3 08:17:59 2019
@@ -13470,7 +13470,6 @@ ExprResult Sema::CreateBuiltinUnaryOp(So
     if (Input.isInvalid())
       return ExprError();
     resultType = Input.get()->getType();
-
     if (resultType->isDependentType())
       break;
     // C99 6.5.3.3p1. We allow complex int and float as a GCC extension.
@@ -13478,6 +13477,9 @@ ExprResult Sema::CreateBuiltinUnaryOp(So
       // C99 does not support '~' for complex conjugation.
       Diag(OpLoc, diag::ext_integer_complement_complex)
           << resultType << Input.get()->getSourceRange();
+    else if (Input.get()->IgnoreParenImpCasts()->getType()->isBooleanType())
+      Diag(OpLoc, diag::warn_bitwise_negation_bool)
+          << FixItHint::CreateReplacement(OpLoc, "!");
     else if (resultType->hasIntegerRepresentation())
       break;
     else if (resultType->isExtVectorType() && Context.getLangOpts().OpenCL) {

Added: cfe/trunk/test/Sema/warn-bitwise-negation-bool.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-bitwise-negation-bool.c?rev=373614&view=auto
==============================================================================
--- cfe/trunk/test/Sema/warn-bitwise-negation-bool.c (added)
+++ cfe/trunk/test/Sema/warn-bitwise-negation-bool.c Thu Oct  3 08:17:59 2019
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wbool-operation %s
+// RUN: %clang_cc1 -x c -fsyntax-only -verify %s
+// RUN: %clang_cc1 -x c -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wbool-operation %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+#ifdef __cplusplus
+typedef bool boolean;
+#else
+typedef _Bool boolean;
+#endif
+
+void test(boolean b, int i) {
+  b = ~b; // expected-warning {{bitwise negation of a boolean expression always evaluates to 'true'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:8}:"!"
+  b = ~(b); // expected-warning {{bitwise negation of a boolean expression always evaluates to 'true'}}
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:8}:"!"
+  b = ~i;
+}