r177162 - c: add the missing binary operatory when checking

[jahanian]

On Mar 15, 2013, at 10:14 AM, David Blaikie <dblaikie at gmail.com> wrote:

> On Fri, Mar 15, 2013 at 10:11 AM, jahanian <fjahanian at apple.com> wrote:
>> 
>> On Mar 15, 2013, at 10:10 AM, David Blaikie <dblaikie at gmail.com> wrote:
>> 
>> On Fri, Mar 15, 2013 at 9:36 AM, Fariborz Jahanian <fjahanian at apple.com>
>> wrote:
>> 
>> Author: fjahanian
>> Date: Fri Mar 15 11:36:04 2013
>> New Revision: 177162
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=177162&view=rev
>> Log:
>> c: add the missing binary operatory when checking
>> for integer overflow. // rdar://13423975
>> 
>> Modified:
>>   cfe/trunk/lib/Sema/SemaChecking.cpp
>>   cfe/trunk/test/Sema/switch-1.c
>> 
>> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=177162&r1=177161&r2=177162&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Fri Mar 15 11:36:04 2013
>> @@ -5188,7 +5188,7 @@ void Sema::CheckImplicitConversions(Expr
>> void Sema::CheckForIntOverflow (Expr *E) {
>>  if (const BinaryOperator *BExpr =
>> dyn_cast<BinaryOperator>(E->IgnoreParens())) {
>>    unsigned Opc = BExpr->getOpcode();
>> -    if (Opc != BO_Add && Opc != BO_Sub && Opc != BO_Mul)
>> +    if (Opc != BO_Add && Opc != BO_Sub && Opc != BO_Mul && Opc != BO_Div)
>>      return;
>>    llvm::SmallVector<PartialDiagnosticAt, 4> Diags;
>>    E->EvaluateForOverflow(Context, &Diags);
>> 
>> Modified: cfe/trunk/test/Sema/switch-1.c
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/switch-1.c?rev=177162&r1=177161&r2=177162&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/Sema/switch-1.c (original)
>> +++ cfe/trunk/test/Sema/switch-1.c Fri Mar 15 11:36:04 2013
>> @@ -1,6 +1,7 @@
>> // RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-apple-darwin10 %s
>> // RUN: %clang_cc1 -x c++ -fsyntax-only -verify -triple
>> x86_64-apple-darwin10 %s
>> // rdar://11577384
>> +// rdar://13423975
>> 
>> int f(int i) {
>>  switch (i) {
>> @@ -10,6 +11,8 @@ int f(int i) {
>>      return 2;
>>    case (123456 *789012) + 1:  // expected-warning {{overflow in
>> expression; result is -1375982336 with type 'int'}}
>>      return 3;
>> +    case (2147483647*4)/4:     // expected-warning {{overflow in
>> expression; result is -4 with type 'int'}}
>> 
>> 
>> Yeah, I'm with Jordan here - why are we warning about the division.
>> Division can't cause overflow. Shouldn't we be warning about that
>> multiplication?
>> 
>> 
>> We are warning about multiplication.
> 
> Then why are we selecting which binary operators to "see" through?
> Which expression would we not want to see through to perform this
> warning?

Come to think of it. There is no reason for it. Patch is coming.
- Fariborz


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