For self-comparison warning, check the source location of both the LHS and RHS to see if they

are expanded from macros (and if so, omit the warning).  Previously we were just looking at the
location of the binary expression.

Fixes <rdar://problem/8435950>.

llvm-svn: 114044

2 files changed, 15 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index a99d118d2bc..20315084703 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -5437,7 +5437,9 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
   QualType rType = rex->getType();
 
   if (!lType->hasFloatingRepresentation() &&
-      !(lType->isBlockPointerType() && isRelational)) {
+      !(lType->isBlockPointerType() && isRelational) &&
+      !lex->getLocStart().isMacroID() &&
+      !rex->getLocStart().isMacroID()) {
     // For non-floating point types, check for self-comparisons of the form
     // x == x, x != x, x < x, etc.  These always evaluate to a constant, and
     // often indicate logic errors in the program.
@@ -5452,7 +5454,7 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
     Expr *RHSStripped = rex->IgnoreParens();
     if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LHSStripped)) {
       if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RHSStripped)) {
-        if (DRL->getDecl() == DRR->getDecl() && !Loc.isMacroID() &&
+        if (DRL->getDecl() == DRR->getDecl() &&
             !IsWithinTemplateSpecialization(DRL->getDecl())) {
           DiagRuntimeBehavior(Loc, PDiag(diag::warn_comparison_always)
                               << 0 // self-
diff --git a/clang/test/Sema/self-comparison.c b/clang/test/Sema/self-comparison.c
index c5c0611e7c9..edb3a6a4c8a 100644
--- a/clang/test/Sema/self-comparison.c
+++ b/clang/test/Sema/self-comparison.c
@@ -75,3 +75,14 @@ int array_comparisons() {
 
 }
 
+// Don't issue a warning when either the left or right side of the comparison
+// results from a macro expansion.  <rdar://problem/8435950>
+#define R8435950_A i 
+#define R8435950_B i 
+
+int R8435950(int i) {
+  if (R8435950_A == R8435950_B) // no-warning
+   return 0;
+  return 1;
+}
+