Don't try to fold comparisons between the address of an object and an arbitrary integer constant. Fixes regression from r143334.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143374 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 9 insertions, 0 deletions

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index b34b59d907..5a65038a5f 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -1981,6 +1981,12 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
         // unspecified or undefined behavior.
         if (!E->isEqualityOp())
           return false;
+        // A constant address may compare equal to the address of a symbol.
+        // The one exception is that address of an object cannot compare equal
+        // to the null pointer.
+        if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
+            (!RHSValue.Base && !RHSValue.Offset.isZero()))
+          return false;
         // It's implementation-defined whether distinct literals will have
         // distinct addresses. We define it to be unspecified.
         if (IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue))
diff --git a/test/SemaCXX/constant-expression-cxx11.cpp b/test/SemaCXX/constant-expression-cxx11.cpp
index 8c845a7bd9..f706e150b4 100644
--- a/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/test/SemaCXX/constant-expression-cxx11.cpp
@@ -200,6 +200,9 @@ constexpr bool s6 = &x > &x;
 constexpr S* sptr = &s;
 constexpr bool dyncast = sptr == dynamic_cast<S*>(sptr);
 
+extern char externalvar[];
+constexpr bool constaddress = (void *)externalvar == (void *)0x4000UL;  // expected-error {{must be initialized by a constant expression}}
+
 using check = int[m1 + (m2<<1) + (m3<<2) + (m4<<3) + (m5<<4) + (m6<<5) +
                   (n1<<6) + (n2<<7) + (n7<<8) + (n8<<9) + (g1<<10) + (g2<<11) +
                (s1<<12) + (s2<<13) + (s3<<14) + (s4<<15) + (s5<<16) + (s6<<17)];