From: David Bolvansky <david.bolvansky@gmail.com>
Date: Mon, 7 Oct 2019 21:57:03 +0000 (+0000)
Subject: [Diagnostics] Emit better -Wbool-operation's warning message if we known that the... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bfb7afed5cdfdf021937d28826861825feb84969;p=clang

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



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@373973 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index c54380639a..23cedcab27 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -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<
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index eeddff6c71..de8e1ef87a 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -11896,6 +11896,13 @@ static void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC,
   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)) {
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 3cb999dacc..f08b616809 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -13479,10 +13479,6 @@ ExprResult Sema::CreateBuiltinUnaryOp(SourceLocation OpLoc,
       // 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) {
diff --git a/test/Sema/warn-bitwise-negation-bool.c b/test/Sema/warn-bitwise-negation-bool.c
index 435d783439..c74705bc76 100644
--- a/test/Sema/warn-bitwise-negation-bool.c
+++ b/test/Sema/warn-bitwise-negation-bool.c
@@ -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}:"!"
 }