On 01/10/2018 01:26 PM, Martin Sebor wrote: > To avoid issuing duplicate warnings for the same function call > in the source code the -Wrestrict warning code makes sure > the no-warning bit is propagated between trees and GIMPLE and > tested before issuing a warning. But the warning also detects > some of the same problems as -Wstringop-overflow, and that > warning was not updated to pay attention to the no-warning bit. > This can in turn lead to two warnings for what boils down to > the same bug. The warnings can be confusing when the first > one references the function as it appears in the source code > and the second one the one it was transformed to by GCC after > the first warning was issued. > > The attached patch corrects this oversight by having > the buffer overflow checker test the no-warning bit and skip > issuing a diagnostic. (The function that does the overflow > checking still runs so that it can continue to indicate to its > callers whether an overflow has been detected.) > > Bootstrap on x86_64-linux in progress. > > Martin > > gcc-83508.diff > > > PR other/83508 - c-c++-common/Wrestrict.c fails since r255836 > > gcc/testsuite/ChangeLog: > > PR other/83508 > * gcc.dg/Wstringop-overflow-2.c: New test. > > gcc/ChangeLog: > > PR other/83508 > * builtins.c (check_access): Avoid warning when the no-warning bit > is set. Would it be better to check for TREE_NO_WARNING at the very start of check_access rather than sprinkling it at various sites later in the code?
Jeff
