From: Eli Friedman Date: Mon, 31 Oct 2011 22:28:05 +0000 (+0000) Subject: Don't try to fold comparisons between the address of an object and an arbitrary integ... X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ffbda40a1fb7169591dc01771f3511178a2f727c;p=clang 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 --- 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(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)];