r373973 - [Diagnostics] Emit better -Wbool-operation's warning message if we known that the result is always true

[David Bolvansky via cfe-commits]

Author: xbolva00
Date: Mon Oct  7 14:57:03 2019
New Revision: 373973

URL: http://llvm.org/viewvc/llvm-project?rev=373973&view=rev
Log:
[Diagnostics] Emit better -Wbool-operation's warning message if we known that the result is always true


Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaChecking.cpp
    cfe/trunk/lib/Sema/SemaExpr.cpp
    cfe/trunk/test/Sema/warn-bitwise-negation-bool.c

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=373973&r1=373972&r2=373973&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Oct  7 14:57:03 2019
@@ -6638,7 +6638,8 @@ def note_member_declared_here : Note<
 def note_member_first_declared_here : Note<
   "member %0 first declared here">;
 def warn_bitwise_negation_bool : Warning<
-  "bitwise negation of a boolean expression; did you mean logical negation?">,
+  "bitwise negation of a boolean expression%select{;| always evaluates to 'true';}0 "
+  "did you mean logical negation?">,
   InGroup<DiagGroup<"bool-operation">>;
 def err_decrement_bool : Error<"cannot decrement expression of type bool">;
 def warn_increment_bool : Warning<

Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=373973&r1=373972&r2=373973&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Mon Oct  7 14:57:03 2019
@@ -11896,6 +11896,13 @@ static void AnalyzeImplicitConversions(S
   if (E->isTypeDependent() || E->isValueDependent())
     return;
 
+  if (const auto *UO = dyn_cast<UnaryOperator>(E))
+    if (UO->getOpcode() == UO_Not &&
+        UO->getSubExpr()->isKnownToHaveBooleanValue())
+      S.Diag(UO->getBeginLoc(), diag::warn_bitwise_negation_bool)
+          << OrigE->getSourceRange() << T->isBooleanType()
+          << FixItHint::CreateReplacement(UO->getBeginLoc(), "!");
+
   // For conditional operators, we analyze the arguments as if they
   // were being fed directly into the output.
   if (isa<ConditionalOperator>(E)) {

Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=373973&r1=373972&r2=373973&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Mon Oct  7 14:57:03 2019
@@ -13479,10 +13479,6 @@ 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()->isKnownToHaveBooleanValue())
-      Diag(OpLoc, diag::warn_bitwise_negation_bool)
-          << Input.get()->getSourceRange()
-          << FixItHint::CreateReplacement(OpLoc, "!");
     else if (resultType->hasIntegerRepresentation())
       break;
     else if (resultType->isExtVectorType() && Context.getLangOpts().OpenCL) {

Modified: 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=373973&r1=373972&r2=373973&view=diff
==============================================================================
--- cfe/trunk/test/Sema/warn-bitwise-negation-bool.c (original)
+++ cfe/trunk/test/Sema/warn-bitwise-negation-bool.c Mon Oct  7 14:57:03 2019
@@ -12,13 +12,13 @@ typedef _Bool boolean;
 #endif
 
 void test(boolean b, int i) {
-  b = ~b; // expected-warning {{bitwise negation of a boolean expression; did you mean logical negation?}}
+  b = ~b; // expected-warning {{bitwise negation of a boolean expression always evaluates to 'true'; did you mean logical negation?}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:8}:"!"
-  b = ~(b); // expected-warning {{bitwise negation of a boolean expression; did you mean logical negation?}}
+  b = ~(b); // expected-warning {{bitwise negation of a boolean expression always evaluates to 'true'; did you mean logical negation?}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:8}:"!"
   b = ~i;
   i = ~b; // expected-warning {{bitwise negation of a boolean expression; did you mean logical negation?}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:8}:"!"
-  b = ~(i > 4); // expected-warning {{bitwise negation of a boolean expression; did you mean logical negation?}}
+  b = ~(i > 4); // expected-warning {{bitwise negation of a boolean expression always evaluates to 'true'; did you mean logical negation?}}
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:8}:"!"
 }