http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51712
--- Comment #2 from Jonathan Nieder <jrnieder at gmail dot com> 2012-03-26 20:12:17 UTC --- Clang does not consider "arg >= FOO" to be a comparison against 0. | commit e3b159c0 | Author: Ted Kremenek <kreme...@apple.com> | Date: Thu Sep 23 21:43:44 2010 +0000 | | When warning about comparing an unsigned int to being >= 0, don't issue a warning if the zero value was an | enum or was expanded from a macro. | | Fixes: <rdar://problem/8414119> | | git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114695 91177308-0d34-0410-b5e6-96231b3b80d8 | | diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp | index 790e7671..c4e86875 100644 | --- a/lib/Sema/SemaChecking.cpp | +++ b/lib/Sema/SemaChecking.cpp | @@ -2449,7 +2449,17 @@ bool IsSameFloatAfterCast(const APValue &value, | | void AnalyzeImplicitConversions(Sema &S, Expr *E); | | -bool IsZero(Sema &S, Expr *E) { | +static bool IsZero(Sema &S, Expr *E) { | + // Suppress cases where we are comparing against an enum constant. | + if (const DeclRefExpr *DR = | + dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) | + if (isa<EnumConstantDecl>(DR->getDecl())) | + return false; | + | + // Suppress cases where the '0' value is expanded from a macro. | + if (E->getLocStart().isMacroID()) | + return false; | + | llvm::APSInt Value; | return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; | } [...]
