On 07/31/2013 01:33 PM, Marek Polacek wrote:
There are still at least two issues though, which is why
bootstrap with -fsanitize=undefined fails:
http://gcc.gnu.org/ml/gcc-patches/2013-07/msg01480.html
This looks like a serious bug, properly caught by -Wuninitialized.
When sanitizing,
in .uninit1 we have
int x.3;
int x.2;
<bb 2>:
x.3_3 = x.2_1(D) >> 1;
x = x.3_3;
Note that x.2 is not initialized.
and when no sanitizing
int x.1;
int x.0;
<bb 2>:
x.0_2 = x;
x.1_3 = x.0_2 >> 1;
x = x.1_3;
But here x.0 is initialized.
http://gcc.gnu.org/ml/gcc-patches/2013-07/msg01536.html
Here, the C++ compiler is wrong to fold away the division by zero, but
given that bug the folding ought to also eliminate the call to the
sanitize function. Seems like you should attach the call to the
questionable expression itself.
Jason
