Hi, This is the 3rd version of the patch for fixing PR109071.
Thanks a lot for San James's help to test the previous 2nd version of the patch on a lot of packages in the wild and provide detailed analysis and filed new bugs. (PR117179, PR117180, etc). >From his testing results, we all feel that this work will be a general improvement in this area and will be very helpful to the end-users. 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; 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. 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. 8. More detailed comments in the patch; bootstrapping and regression testing on both x86 and aarch64. Please let me know any comment and suggestion. Thanks. Qing Qing Zhao (2): Provide more contexts for -Warray-bounds, -Wstringop-* warning messages due to code movements from compiler transformation [PR109071] Add debugging for move history.
