r312750 - [Sema] -Wtautological-compare: handle comparison of unsigned with 0S.
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Fri Sep 8 14:18:14 PDT 2017
On Fri, Sep 8, 2017 at 2:09 PM, Roman Lebedev <lebedev.ri at gmail.com> wrote:
> On Fri, Sep 8, 2017 at 11:45 PM, Hans Wennborg <hans at chromium.org> wrote:
>> On Fri, Sep 8, 2017 at 4:48 AM, Sam McCall via cfe-commits
>> <cfe-commits at lists.llvm.org> wrote:
>>> Nice fix! It catches a lot of new cases on our codebase, all technically
>>> correct so far.
>>>
>>> A couple of issues though:
>>> A) Rollout - until we've completely cleaned up, we need to disable
>>> -Wtautological-compare entirely, which is a valuable check. I imagine anyone
>>> else using -Werror is in the same boat.
>>> What do you think about putting the new warnings behind a subcategory? (e.g.
>>> -Wtautological-compare-unsigned-zero, implied by -Wtautological-compare)
>>> It's an ugly artifact of the history here, but allows this fix to be rolled
>>> out in a controlled way.
>>>
>>> B) Enums (not new I guess). Typical case: if (enum < 0 || enum > MAX)
>>> The warning strongly suggests that the enum < 0 check has no effect (for
>>> enums with nonnegative ranges).
>>> Clang doesn't seem to optimize such checks out though, and they seem likely
>>> to catch bugs in some cases. Yes, only if there's UB elsewhere, but I assume
>>> not optimizing out these checks indicates a deliberate decision to stay
>>> somewhat compatible with a technically-incorrect mental model.
>>> If this is the case, should we move these to a -Wtautological-compare-enum
>>> subcategory?
>>
>> Just another data point: we're seeing this a lot in Chromium, e.g.
>>
>> enum MediaDeviceType {
>> MEDIA_DEVICE_TYPE_AUDIO_INPUT,
>> MEDIA_DEVICE_TYPE_VIDEO_INPUT,
>> MEDIA_DEVICE_TYPE_AUDIO_OUTPUT,
>> NUM_MEDIA_DEVICE_TYPES,
>> };
>>
>> inline bool IsValidMediaDeviceType(MediaDeviceType type) {
>> return type >= 0 && type < NUM_MEDIA_DEVICE_TYPES;
>> }
>>
>> ../../content/common/media/media_devices.h:53:15: warning: comparison
>> of unsigned enum expression >= 0 is always true
>> [-Wtautological-unsigned-zero-compare]
>> return type >= 0 && type < NUM_MEDIA_DEVICE_TYPES;
>> ~~~~ ^ ~
>>
>> The problem is that the signedness of the enum varies per platform.
>> For example, when targeting Windows the underlying type is 'int' by
>> default, and then the comparison isn't tautological.
>
> Interesting. My first thought was to explicitly specify enum as signed:
>
> enum MediaDeviceType : signed int {
> MEDIA_DEVICE_TYPE_AUDIO_INPUT = 0,
> MEDIA_DEVICE_TYPE_VIDEO_INPUT,
> MEDIA_DEVICE_TYPE_AUDIO_OUTPUT,
> NUM_MEDIA_DEVICE_TYPES,
> };
>
> inline bool IsValidMediaDeviceType(MediaDeviceType type) {
> return type >= 0U && type < NUM_MEDIA_DEVICE_TYPES;
> }
>
> But it still seem to warn, and *that* sounds like a bug.
> Please open a new bugreport.
I'm reporting it here :-)
> As for different default signedness, i'm not sure what is there to do. Does
> not sound like a problem for this diagnostic to intentionally avoid to
> be honest.
I think it is a problem for this warning. If a user sees the warning
and removes the "type >= 0" check, thinking that it was unnecessary
because the compiler told them so, they have now introduced a bug in
the code.
>>> On Fri, Sep 8, 2017 at 12:14 AM, Roman Lebedev via cfe-commits
>>> <cfe-commits at lists.llvm.org> wrote:
>>>>
>>>> Author: lebedevri
>>>> Date: Thu Sep 7 15:14:25 2017
>>>> New Revision: 312750
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=312750&view=rev
>>>> Log:
>>>> [Sema] -Wtautological-compare: handle comparison of unsigned with 0S.
>>>>
>>>> Summary:
>>>> This is a first half(?) of a fix for the following bug:
>>>> https://bugs.llvm.org/show_bug.cgi?id=34147 (gcc -Wtype-limits)
>>>>
>>>> GCC's -Wtype-limits does warn on comparison of unsigned value
>>>> with signed zero (as in, with 0), but clang only warns if the
>>>> zero is unsigned (i.e. 0U).
>>>>
>>>> Also, be careful not to double-warn, or falsely warn on
>>>> comparison of signed/fp variable and signed 0.
>>>>
>>>> Yes, all these testcases are needed.
>>>>
>>>> Testing: $ ninja check-clang-sema check-clang-semacxx
>>>> Also, no new warnings for clang stage-2 build.
>>>>
>>>> Reviewers: rjmccall, rsmith, aaron.ballman
>>>>
>>>> Reviewed By: rjmccall
>>>>
>>>> Subscribers: cfe-commits
>>>>
>>>> Tags: #clang
>>>>
>>>> Differential Revision: https://reviews.llvm.org/D37565
>>>>
>>>> Modified:
>>>> cfe/trunk/docs/ReleaseNotes.rst
>>>> cfe/trunk/lib/Sema/SemaChecking.cpp
>>>> cfe/trunk/test/Sema/compare.c
>>>> cfe/trunk/test/Sema/outof-range-constant-compare.c
>>>> cfe/trunk/test/SemaCXX/compare.cpp
>>>>
>>>> Modified: cfe/trunk/docs/ReleaseNotes.rst
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/ReleaseNotes.rst?rev=312750&r1=312749&r2=312750&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/docs/ReleaseNotes.rst (original)
>>>> +++ cfe/trunk/docs/ReleaseNotes.rst Thu Sep 7 15:14:25 2017
>>>> @@ -71,6 +71,13 @@ Improvements to Clang's diagnostics
>>>> errors/warnings, as the system frameworks might add a method with the
>>>> same
>>>> selector which could make the message send to ``id`` ambiguous.
>>>>
>>>> +- ``-Wtautological-compare`` now warns when comparing an unsigned integer
>>>> and 0
>>>> + regardless of whether the constant is signed or unsigned."
>>>> +
>>>> +- ``-Wtautological-compare`` now warns about comparing a signed integer
>>>> and 0
>>>> + when the signed integer is coerced to an unsigned type for the
>>>> comparison.
>>>> + ``-Wsign-compare`` was adjusted not to warn in this case.
>>>> +
>>>> Non-comprehensive list of changes in this release
>>>> -------------------------------------------------
>>>>
>>>>
>>>> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=312750&r1=312749&r2=312750&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>>>> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Thu Sep 7 15:14:25 2017
>>>> @@ -8567,32 +8567,51 @@ bool HasEnumType(Expr *E) {
>>>> return E->getType()->isEnumeralType();
>>>> }
>>>>
>>>> -void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
>>>> +bool isNonBooleanUnsignedValue(Expr *E) {
>>>> + // We are checking that the expression is not known to have boolean
>>>> value,
>>>> + // is an integer type; and is either unsigned after implicit casts,
>>>> + // or was unsigned before implicit casts.
>>>> + return !E->isKnownToHaveBooleanValue() && E->getType()->isIntegerType()
>>>> &&
>>>> + (!E->getType()->isSignedIntegerType() ||
>>>> + !E->IgnoreParenImpCasts()->getType()->isSignedIntegerType());
>>>> +}
>>>> +
>>>> +bool CheckTautologicalComparisonWithZero(Sema &S, BinaryOperator *E) {
>>>> // Disable warning in template instantiations.
>>>> if (S.inTemplateInstantiation())
>>>> - return;
>>>> + return false;
>>>> +
>>>> + // bool values are handled by DiagnoseOutOfRangeComparison().
>>>>
>>>> BinaryOperatorKind op = E->getOpcode();
>>>> if (E->isValueDependent())
>>>> - return;
>>>> + return false;
>>>>
>>>> - if (op == BO_LT && IsZero(S, E->getRHS())) {
>>>> + Expr *LHS = E->getLHS();
>>>> + Expr *RHS = E->getRHS();
>>>> +
>>>> + bool Match = true;
>>>> +
>>>> + if (op == BO_LT && isNonBooleanUnsignedValue(LHS) && IsZero(S, RHS)) {
>>>> S.Diag(E->getOperatorLoc(),
>>>> diag::warn_lunsigned_always_true_comparison)
>>>> - << "< 0" << "false" << HasEnumType(E->getLHS())
>>>> - << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
>>>> - } else if (op == BO_GE && IsZero(S, E->getRHS())) {
>>>> + << "< 0" << "false" << HasEnumType(LHS)
>>>> + << LHS->getSourceRange() << RHS->getSourceRange();
>>>> + } else if (op == BO_GE && isNonBooleanUnsignedValue(LHS) && IsZero(S,
>>>> RHS)) {
>>>> S.Diag(E->getOperatorLoc(),
>>>> diag::warn_lunsigned_always_true_comparison)
>>>> - << ">= 0" << "true" << HasEnumType(E->getLHS())
>>>> - << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
>>>> - } else if (op == BO_GT && IsZero(S, E->getLHS())) {
>>>> + << ">= 0" << "true" << HasEnumType(LHS)
>>>> + << LHS->getSourceRange() << RHS->getSourceRange();
>>>> + } else if (op == BO_GT && isNonBooleanUnsignedValue(RHS) && IsZero(S,
>>>> LHS)) {
>>>> S.Diag(E->getOperatorLoc(),
>>>> diag::warn_runsigned_always_true_comparison)
>>>> - << "0 >" << "false" << HasEnumType(E->getRHS())
>>>> - << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
>>>> - } else if (op == BO_LE && IsZero(S, E->getLHS())) {
>>>> + << "0 >" << "false" << HasEnumType(RHS)
>>>> + << LHS->getSourceRange() << RHS->getSourceRange();
>>>> + } else if (op == BO_LE && isNonBooleanUnsignedValue(RHS) && IsZero(S,
>>>> LHS)) {
>>>> S.Diag(E->getOperatorLoc(),
>>>> diag::warn_runsigned_always_true_comparison)
>>>> - << "0 <=" << "true" << HasEnumType(E->getRHS())
>>>> - << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
>>>> - }
>>>> + << "0 <=" << "true" << HasEnumType(RHS)
>>>> + << LHS->getSourceRange() << RHS->getSourceRange();
>>>> + } else
>>>> + Match = false;
>>>> +
>>>> + return Match;
>>>> }
>>>>
>>>> void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, Expr
>>>> *Constant,
>>>> @@ -8612,7 +8631,7 @@ void DiagnoseOutOfRangeComparison(Sema &
>>>>
>>>> bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue();
>>>>
>>>> - // 0 values are handled later by CheckTrivialUnsignedComparison().
>>>> + // 0 values are handled later by CheckTautologicalComparisonWithZero().
>>>> if ((Value == 0) && (!OtherIsBooleanType))
>>>> return;
>>>>
>>>> @@ -8849,16 +8868,22 @@ void AnalyzeComparison(Sema &S, BinaryOp
>>>> (IsRHSIntegralLiteral && IsLHSIntegralLiteral);
>>>> } else if (!T->hasUnsignedIntegerRepresentation())
>>>> IsComparisonConstant = E->isIntegerConstantExpr(S.Context);
>>>> -
>>>> +
>>>> + // We don't care about value-dependent expressions or expressions
>>>> + // whose result is a constant.
>>>> + if (IsComparisonConstant)
>>>> + return AnalyzeImpConvsInComparison(S, E);
>>>> +
>>>> + // If this is a tautological comparison, suppress -Wsign-compare.
>>>> + if (CheckTautologicalComparisonWithZero(S, E))
>>>> + return AnalyzeImpConvsInComparison(S, E);
>>>> +
>>>> // We don't do anything special if this isn't an unsigned integral
>>>> // comparison: we're only interested in integral comparisons, and
>>>> // signed comparisons only happen in cases we don't care to warn about.
>>>> - //
>>>> - // We also don't care about value-dependent expressions or expressions
>>>> - // whose result is a constant.
>>>> - if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant)
>>>> + if (!T->hasUnsignedIntegerRepresentation())
>>>> return AnalyzeImpConvsInComparison(S, E);
>>>> -
>>>> +
>>>> // Check to see if one of the (unmodified) operands is of different
>>>> // signedness.
>>>> Expr *signedOperand, *unsignedOperand;
>>>> @@ -8871,7 +8896,6 @@ void AnalyzeComparison(Sema &S, BinaryOp
>>>> signedOperand = RHS;
>>>> unsignedOperand = LHS;
>>>> } else {
>>>> - CheckTrivialUnsignedComparison(S, E);
>>>> return AnalyzeImpConvsInComparison(S, E);
>>>> }
>>>>
>>>> @@ -8883,11 +8907,9 @@ void AnalyzeComparison(Sema &S, BinaryOp
>>>> AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
>>>> AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
>>>>
>>>> - // If the signed range is non-negative, -Wsign-compare won't fire,
>>>> - // but we should still check for comparisons which are always true
>>>> - // or false.
>>>> + // If the signed range is non-negative, -Wsign-compare won't fire.
>>>> if (signedRange.NonNegative)
>>>> - return CheckTrivialUnsignedComparison(S, E);
>>>> + return;
>>>>
>>>> // For (in)equality comparisons, if the unsigned operand is a
>>>> // constant which cannot collide with a overflowed signed operand,
>>>>
>>>> Modified: cfe/trunk/test/Sema/compare.c
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/compare.c?rev=312750&r1=312749&r2=312750&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/test/Sema/compare.c (original)
>>>> +++ cfe/trunk/test/Sema/compare.c Thu Sep 7 15:14:25 2017
>>>> @@ -77,7 +77,7 @@ int ints(long a, unsigned long b) {
>>>> ((int) a == (unsigned int) B) +
>>>> ((short) a == (unsigned short) B) +
>>>> ((signed char) a == (unsigned char) B) +
>>>> - (a < (unsigned long) B) + // expected-warning {{comparison of
>>>> integers of different signs}}
>>>> + (a < (unsigned long) B) + // expected-warning {{comparison of
>>>> unsigned expression < 0 is always false}}
>>>> (a < (unsigned int) B) +
>>>> (a < (unsigned short) B) +
>>>> (a < (unsigned char) B) +
>>>> @@ -85,8 +85,8 @@ int ints(long a, unsigned long b) {
>>>> ((int) a < B) +
>>>> ((short) a < B) +
>>>> ((signed char) a < B) +
>>>> - ((long) a < (unsigned long) B) + // expected-warning
>>>> {{comparison of integers of different signs}}
>>>> - ((int) a < (unsigned int) B) + // expected-warning {{comparison
>>>> of integers of different signs}}
>>>> + ((long) a < (unsigned long) B) + // expected-warning
>>>> {{comparison of unsigned expression < 0 is always false}}
>>>> + ((int) a < (unsigned int) B) + // expected-warning {{comparison
>>>> of unsigned expression < 0 is always false}}
>>>> ((short) a < (unsigned short) B) +
>>>> ((signed char) a < (unsigned char) B) +
>>>>
>>>>
>>>> Modified: cfe/trunk/test/Sema/outof-range-constant-compare.c
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/outof-range-constant-compare.c?rev=312750&r1=312749&r2=312750&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/test/Sema/outof-range-constant-compare.c (original)
>>>> +++ cfe/trunk/test/Sema/outof-range-constant-compare.c Thu Sep 7 15:14:25
>>>> 2017
>>>> @@ -6,6 +6,59 @@ int value(void);
>>>> int main()
>>>> {
>>>> int a = value();
>>>> +
>>>> + if (a == 0x0000000000000000L)
>>>> + return 0;
>>>> + if (a != 0x0000000000000000L)
>>>> + return 0;
>>>> + if (a < 0x0000000000000000L)
>>>> + return 0;
>>>> + if (a <= 0x0000000000000000L)
>>>> + return 0;
>>>> + if (a > 0x0000000000000000L)
>>>> + return 0;
>>>> + if (a >= 0x0000000000000000L)
>>>> + return 0;
>>>> +
>>>> + if (0x0000000000000000L == a)
>>>> + return 0;
>>>> + if (0x0000000000000000L != a)
>>>> + return 0;
>>>> + if (0x0000000000000000L < a)
>>>> + return 0;
>>>> + if (0x0000000000000000L <= a)
>>>> + return 0;
>>>> + if (0x0000000000000000L > a)
>>>> + return 0;
>>>> + if (0x0000000000000000L >= a)
>>>> + return 0;
>>>> +
>>>> + if (a == 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (a != 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (a < 0x0000000000000000UL) // expected-warning {{comparison of
>>>> unsigned expression < 0 is always false}}
>>>> + return 0;
>>>> + if (a <= 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (a > 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (a >= 0x0000000000000000UL) // expected-warning {{comparison of
>>>> unsigned expression >= 0 is always true}}
>>>> + return 0;
>>>> +
>>>> + if (0x0000000000000000UL == a)
>>>> + return 0;
>>>> + if (0x0000000000000000UL != a)
>>>> + return 0;
>>>> + if (0x0000000000000000UL < a)
>>>> + return 0;
>>>> + if (0x0000000000000000UL <= a) // expected-warning {{comparison of 0
>>>> <= unsigned expression is always true}}
>>>> + return 0;
>>>> + if (0x0000000000000000UL > a) // expected-warning {{comparison of 0 >
>>>> unsigned expression is always false}}
>>>> + return 0;
>>>> + if (0x0000000000000000UL >= a)
>>>> + return 0;
>>>> +
>>>> if (a == 0x1234567812345678L) // expected-warning {{comparison of
>>>> constant 1311768465173141112 with expression of type 'int' is always false}}
>>>> return 0;
>>>> if (a != 0x1234567812345678L) // expected-warning {{comparison of
>>>> constant 1311768465173141112 with expression of type 'int' is always true}}
>>>> @@ -74,6 +127,7 @@ int main()
>>>> return 0;
>>>> if (0x1234567812345678L >= s) // expected-warning {{comparison of
>>>> constant 1311768465173141112 with expression of type 'short' is always
>>>> true}}
>>>> return 0;
>>>> +
>>>> long l = value();
>>>> if (l == 0x1234567812345678L)
>>>> return 0;
>>>> @@ -106,13 +160,13 @@ int main()
>>>> return 0;
>>>> if (un != 0x0000000000000000L)
>>>> return 0;
>>>> - if (un < 0x0000000000000000L)
>>>> + if (un < 0x0000000000000000L) // expected-warning {{comparison of
>>>> unsigned expression < 0 is always false}}
>>>> return 0;
>>>> if (un <= 0x0000000000000000L)
>>>> return 0;
>>>> if (un > 0x0000000000000000L)
>>>> return 0;
>>>> - if (un >= 0x0000000000000000L)
>>>> + if (un >= 0x0000000000000000L) // expected-warning {{comparison of
>>>> unsigned expression >= 0 is always true}}
>>>> return 0;
>>>>
>>>> if (0x0000000000000000L == un)
>>>> @@ -121,19 +175,92 @@ int main()
>>>> return 0;
>>>> if (0x0000000000000000L < un)
>>>> return 0;
>>>> - if (0x0000000000000000L <= un)
>>>> + if (0x0000000000000000L <= un) // expected-warning {{comparison of 0
>>>> <= unsigned expression is always true}}
>>>> return 0;
>>>> - if (0x0000000000000000L > un)
>>>> + if (0x0000000000000000L > un) // expected-warning {{comparison of 0 >
>>>> unsigned expression is always false}}
>>>> return 0;
>>>> if (0x0000000000000000L >= un)
>>>> return 0;
>>>> +
>>>> + if (un == 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (un != 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (un < 0x0000000000000000UL) // expected-warning {{comparison of
>>>> unsigned expression < 0 is always false}}
>>>> + return 0;
>>>> + if (un <= 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (un > 0x0000000000000000UL)
>>>> + return 0;
>>>> + if (un >= 0x0000000000000000UL) // expected-warning {{comparison of
>>>> unsigned expression >= 0 is always true}}
>>>> + return 0;
>>>> +
>>>> + if (0x0000000000000000UL == un)
>>>> + return 0;
>>>> + if (0x0000000000000000UL != un)
>>>> + return 0;
>>>> + if (0x0000000000000000UL < un)
>>>> + return 0;
>>>> + if (0x0000000000000000UL <= un) // expected-warning {{comparison of 0
>>>> <= unsigned expression is always true}}
>>>> + return 0;
>>>> + if (0x0000000000000000UL > un) // expected-warning {{comparison of 0
>>>> > unsigned expression is always false}}
>>>> + return 0;
>>>> + if (0x0000000000000000UL >= un)
>>>> + return 0;
>>>> +
>>>> float fl = 0;
>>>> - if (fl == 0x0000000000000000L) // no warning
>>>> - return 0;
>>>> + if (fl == 0x0000000000000000L)
>>>> + return 0;
>>>> + if (fl != 0x0000000000000000L)
>>>> + return 0;
>>>> + if (fl < 0x0000000000000000L)
>>>> + return 0;
>>>> + if (fl <= 0x0000000000000000L)
>>>> + return 0;
>>>> + if (fl > 0x0000000000000000L)
>>>> + return 0;
>>>> + if (fl >= 0x0000000000000000L)
>>>> + return 0;
>>>>
>>>> - float dl = 0;
>>>> - if (dl == 0x0000000000000000L) // no warning
>>>> - return 0;
>>>> + if (0x0000000000000000L == fl)
>>>> + return 0;
>>>> + if (0x0000000000000000L != fl)
>>>> + return 0;
>>>> + if (0x0000000000000000L < fl)
>>>> + return 0;
>>>> + if (0x0000000000000000L <= fl)
>>>> + return 0;
>>>> + if (0x0000000000000000L > fl)
>>>> + return 0;
>>>> + if (0x0000000000000000L >= fl)
>>>> + return 0;
>>>> +
>>>> + double dl = 0;
>>>> + if (dl == 0x0000000000000000L)
>>>> + return 0;
>>>> + if (dl != 0x0000000000000000L)
>>>> + return 0;
>>>> + if (dl < 0x0000000000000000L)
>>>> + return 0;
>>>> + if (dl <= 0x0000000000000000L)
>>>> + return 0;
>>>> + if (dl > 0x0000000000000000L)
>>>> + return 0;
>>>> + if (dl >= 0x0000000000000000L)
>>>> + return 0;
>>>> +
>>>> + if (0x0000000000000000L == dl)
>>>> + return 0;
>>>> + if (0x0000000000000000L != dl)
>>>> + return 0;
>>>> + if (0x0000000000000000L < dl)
>>>> + return 0;
>>>> + if (0x0000000000000000L <= dl)
>>>> + return 0;
>>>> + if (0x0000000000000000L > dl)
>>>> + return 0;
>>>> + if (0x0000000000000000L >= dl)
>>>> + return 0;
>>>>
>>>> enum E {
>>>> yes,
>>>>
>>>> Modified: cfe/trunk/test/SemaCXX/compare.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/compare.cpp?rev=312750&r1=312749&r2=312750&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/test/SemaCXX/compare.cpp (original)
>>>> +++ cfe/trunk/test/SemaCXX/compare.cpp Thu Sep 7 15:14:25 2017
>>>> @@ -73,7 +73,7 @@ int test0(long a, unsigned long b) {
>>>> ((int) a == (unsigned int) B) +
>>>> ((short) a == (unsigned short) B) +
>>>> ((signed char) a == (unsigned char) B) +
>>>> - (a < (unsigned long) B) + // expected-warning {{comparison of
>>>> integers of different signs}}
>>>> + (a < (unsigned long) B) + // expected-warning {{comparison of
>>>> unsigned expression < 0 is always false}}
>>>> (a < (unsigned int) B) +
>>>> (a < (unsigned short) B) +
>>>> (a < (unsigned char) B) +
>>>> @@ -81,8 +81,8 @@ int test0(long a, unsigned long b) {
>>>> ((int) a < B) +
>>>> ((short) a < B) +
>>>> ((signed char) a < B) +
>>>> - ((long) a < (unsigned long) B) + // expected-warning
>>>> {{comparison of integers of different signs}}
>>>> - ((int) a < (unsigned int) B) + // expected-warning {{comparison
>>>> of integers of different signs}}
>>>> + ((long) a < (unsigned long) B) + // expected-warning
>>>> {{comparison of unsigned expression < 0 is always false}}
>>>> + ((int) a < (unsigned int) B) + // expected-warning {{comparison
>>>> of unsigned expression < 0 is always false}}
>>>> ((short) a < (unsigned short) B) +
>>>> ((signed char) a < (unsigned char) B) +
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> cfe-commits mailing list
>>>> cfe-commits at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>>
>>>
>>>
>>> _______________________________________________
>>> cfe-commits mailing list
>>> cfe-commits at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>>
More information about the cfe-commits
mailing list