[cfe-dev] Possible error in EmitCXXNewAllocSize

[Eli Friedman]

On Sat, Apr 9, 2011 at 11:45 AM, Eli Friedman <eli.friedman at gmail.com> wrote:
> On Sat, Apr 9, 2011 at 11:25 AM, Daniel Schwartz-Narbonne
> <dstwo at princeton.edu> wrote:
>> I was looking through the code for this function, and on line 533,
>> where you check whether an overflow occurred, you say
>>      DidOverflow = CGF.Builder.CreateAnd(DidOverflow, AddDidOverflow);
>> Shouldn't this be an OR?  Doesn't the error occur if either the
>> multiplication or the addition overflowed?
>
> You're right; testcase demonstrating the overflow:
> struct A { char x[1<<16]; ~A(); };
> A* f() { int x = 1<<16; return new A[x]; };
>
> Run this through "clang -x c++ - -o - -S -m32 -emit-llvm -O2", and you
> get "tail call noalias i8* @_Znaj(i32 4)".

Fixed in r129231.

-Eli