On 01/16/2017 05:06 PM, Martin Sebor wrote:
The test case submitted in bug 79095 - [7 regression] spurious
stringop-overflow warning shows that GCC optimizes some loops
into calls to memset with size arguments in excess of the object
size limit. Since such calls will unavoidably lead to a buffer
overflow and memory corruption the attached patch detects them
and replaces them with a trap. That both prevents the buffer
overflow and eliminates the warning.
But doesn't the creation of the bogus memset signal an invalid
transformation in the loop optimizer? ie, if we're going to convert a
loop into a memset, then we'd damn well better be sure the loop bounds
are reasonable.
Jeff
