> On Oct 30, 2024, at 13:38, Sam James <s...@gentoo.org> wrote: > > > Absolutely. Both in terms of improving safety as the whole point of > these warnings is, but also stopping users from being panicked. They > sometimes believe the warnings imply miscompilation because they can't > understand how they would happen otherwise. > > An earlier version of these patches already helped find a real bug in > GNU wget. > > I will be testing these patches and reporting any issues I see (either > in GCC or to projects).
Thanks a lot for the help! > > >> In this patch, we try to provide more contexts for -Warray-bounds, >> -Wstringop-* >> warning messages due to code movements from various compiler transformations. >> >> Control this with a new option -fdiagnostics-details. >> >> Compared to the 2nd version: >> >> https://gcc.gnu.org/pipermail/gcc-patches/2024-July/657150.html >> >> Which is limited to fix PR109071, there are the following major improvement >> to the patch: >> >> 1. All the following current open PRs were identified as the duplications >> of PR109071 and were studied and fixed by this 3rd version of the patch. >> each testing case was added to the patch as a unit-test case: >> >> PR88771 >> PR85788 >> PR108770 >> PR106762 >> PR115274 >> PR117179 >> >> 2. Change the name of the new option from -fdiagnostics-explain-harder >> to -fdiagnostics-details; > > The new name sounds good to me. > >> >> 3. Change the name of the new data structure from "copy_history" to >> "move_history" due to the following reason: >> >> The key feature of the compiler transformation that might provide more >> accurate information to the value-range analysis is: moving a statement >> from the joint point of one specific condition to this condition's >> TRUE or FALSE path. >> >> For example, threadjump and isolate-path transformation make duplicated >> basic block "Ba'" of the original basic block "Ba" that on the joint >> point of a condition "cond", and then move the two basic block "Ba'" >> and "Ba" to the TRUE path and FALSE path of the condition "cond"; on the >> otherhand, tree sink transformation just move some of the statements from >> the joint point of a condition "cond" to one specific path of this >> condition. >> >> So, the new data structure "move_history" will include the following >> information: >> A. the "condition" that triggers the code movement; >> B. whether the code movement is on the true path of the "condition"; >> C. the "compiler transformation" that triggers the code movement. >> >> 4. In addition to backward threadjump, this patch can handle more compiler >> transformations: >> A. forward threadjump; >> B. isolate-path; >> B. tree-sinking; >> >> 5. In addition to -Warray-bound, making -Wstringop-* work as well. > > stringop* are really the most notorious for this so this is very > welcome. > >> >> 6. Adding debugging mechanism to the new data structure “move_history”; >> 7. Adding all the testing cases of the duplicated bugs as the testing cases. > > Can you tag each of those PRs in the ChangeLog so the commit hook > updates those too? Sure, I will add them in the next version. Qing
