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

llvm-svn: 143374
This commit is contained in:
Eli Friedman 2011-10-31 22:28:05 +00:00
parent ce6a5718ce
commit c6be94b3de
2 changed files with 9 additions and 0 deletions
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6
clang/lib/AST/ExprConstant.cpp
View File

@ -1981,6 +1981,12 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
// unspecified or undefined behavior. // unspecified or undefined behavior.
if (!E->isEqualityOp()) if (!E->isEqualityOp())
return false; 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 // It's implementation-defined whether distinct literals will have
// distinct addresses. We define it to be unspecified. // distinct addresses. We define it to be unspecified.
if (IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) if (IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue))

3
clang/test/SemaCXX/constant-expression-cxx11.cpp
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@ -200,6 +200,9 @@ constexpr bool s6 = &x > &x;
constexpr S* sptr = &s; constexpr S* sptr = &s;
constexpr bool dyncast = sptr == dynamic_cast<S*>(sptr); 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) + 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) + (n1<<6) + (n2<<7) + (n7<<8) + (n8<<9) + (g1<<10) + (g2<<11) +
(s1<<12) + (s2<<13) + (s3<<14) + (s4<<15) + (s5<<16) + (s6<<17)]; (s1<<12) + (s2<<13) + (s3<<14) + (s4<<15) + (s5<<16) + (s6<<17)];