From: Anders Carlsson <andersca@mac.com>
Date: Thu, 4 Nov 2010 03:17:43 +0000 (+0000)
Subject: It's OK to use nullptr in relational operators if the other side is a null pointer... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0c8209e40b405fd32f047e95aafdc94054406a58;p=clang

It's OK to use nullptr in relational operators if the other side is a null pointer constant.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118234 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 51bb6315e1..6df818cd7a 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -5735,6 +5735,7 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
           return ResultTy;
         }
       }
+
       // C++ [expr.rel]p2:
       //   [...] Pointer conversions (4.10) and qualification
       //   conversions (4.4) are performed on pointer operands (or on
@@ -5788,10 +5789,14 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
   }
 
   if (getLangOptions().CPlusPlus) {
+    // Comparison of nullptr_t with itself.
+    if (lType->isNullPtrType() && rType->isNullPtrType())
+      return ResultTy;
+    
     // Comparison of pointers with null pointer constants and equality
     // comparisons of member pointers to null pointer constants.
     if (RHSIsNull &&
-        (lType->isPointerType() ||
+        ((lType->isPointerType() || lType->isNullPtrType()) ||
          (!isRelational && lType->isMemberPointerType()))) {
       ImpCastExprToType(rex, lType, 
                         lType->isMemberPointerType()
@@ -5800,7 +5805,7 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
       return ResultTy;
     }
     if (LHSIsNull &&
-        (rType->isPointerType() ||
+        ((rType->isPointerType() || rType->isNullPtrType()) ||
          (!isRelational && rType->isMemberPointerType()))) {
       ImpCastExprToType(lex, rType, 
                         rType->isMemberPointerType()
@@ -5840,10 +5845,6 @@ QualType Sema::CheckCompareOperands(Expr *&lex, Expr *&rex, SourceLocation Loc,
       ImpCastExprToType(rex, T, CK_BitCast);
       return ResultTy;
     }
-
-    // Comparison of nullptr_t with itself.
-    if (lType->isNullPtrType() && rType->isNullPtrType())
-      return ResultTy;
   }
 
   // Handle block pointer types.
diff --git a/test/SemaCXX/nullptr.cpp b/test/SemaCXX/nullptr.cpp
index 0652062388..cc75eab30b 100644
--- a/test/SemaCXX/nullptr.cpp
+++ b/test/SemaCXX/nullptr.cpp
@@ -38,6 +38,10 @@ nullptr_t f(nullptr_t null)
   (void)((void*)0 == nullptr);
   (void)(null <= (void*)0);
   (void)((void*)0 <= nullptr);
+  (void)(0 == nullptr);
+  (void)(nullptr == 0);
+  (void)(nullptr <= 0);
+  (void)(0 <= nullptr);
   (void)(1 > nullptr); // expected-error {{invalid operands to binary expression}}
   (void)(1 != nullptr); // expected-error {{invalid operands to binary expression}}
   (void)(1 + nullptr); // expected-error {{invalid operands to binary expression}}