[SemaCXX] Silence -Wconstant-logical-operand if the operand is a 0/1 from a macro.

Libraries specify enabled/disabled features using macro defs of 0/1, in such cases the -Wconstant-logical-operand
is noise.

rdar://15410291

llvm-svn: 207386

2 files changed, 12 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 6d624adc4eb..595770dc36b 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -8268,7 +8268,8 @@ inline QualType Sema::CheckLogicalOperands( // C99 6.5.[13,14]
     // Parens on the RHS are ignored.
     llvm::APSInt Result;
     if (RHS.get()->EvaluateAsInt(Result, Context))
-      if ((getLangOpts().Bool && !RHS.get()->getType()->isBooleanType()) ||
+      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()
diff --git a/clang/test/SemaCXX/expressions.cpp b/clang/test/SemaCXX/expressions.cpp
index 25a9c841725..1a50c99c590 100644
--- a/clang/test/SemaCXX/expressions.cpp
+++ b/clang/test/SemaCXX/expressions.cpp
@@ -125,3 +125,13 @@ namespace pr16992 {
     return (sizeof T());
   }
 }
+
+void test4() {
+  #define X 0
+  #define Y 1
+  bool r1 = X || Y;
+
+  #define Y2 2
+  bool r2 = X || Y2; // expected-warning {{use of logical '||' with constant operand}} \
+                     // expected-note {{use '|' for a bitwise operation}}
+}