On 11/11/2014 05:15 PM, Jakub Jelinek wrote:
There are also some unsafe code in functions
ubsan_expand_si_overflow_addsub_check, ubsan_expand_si_overflow_mul_check
which uses get_range_info to reduce checks number. As seen before vrp usage
for sanitizers may decrease quality of error detection.
Using VRP is completely intentional there, we don't want to generate too
slow code if you decide you want to optimize your code (for -O0 VRP isn't
performed of course).
On the other hand detection quality is probably more important than
important regardless of optimization level. When I use a checker, I
don't want it to miss bugs due to overly aggressive optimization.
I wish we had some test to check that sanitizer optimizations are indeed
conservative.
-Y
