Sorry, here is the patch. ------------------------------------------------------------------ Sender:bin.cheng <bin.ch...@linux.alibaba.com> Sent At:2020 Jan. 8 (Wed.) 12:58 Recipient:GCC Patches <gcc-patches@gcc.gnu.org> Subject:[PATCH GCC11]Improve uninitialized warning with value range info
Hi, Function use_pred_not_overlap_with_undef_path_pred of pass_late_warn_uninitialized checks if predicate of variable use overlaps with predicate of undefined control flow path. For now, it only checks ssa_var comparing against constant, this can be improved where ssa_var compares against another ssa_var with value range info, as described in comment: + /* Check value range info of rhs, do following transforms: + flag_var < [min, max] -> flag_var < max + flag_var > [min, max] -> flag_var > min + + We can also transform LE_EXPR/GE_EXPR to LT_EXPR/GT_EXPR: + flag_var <= [min, max] -> flag_var < [min, max+1] + flag_var >= [min, max] -> flag_var > [min-1, max] + if no overflow/wrap. */ This change can avoid some false warning. Bootstrap and test on x86_64, any comment? Thanks, bin 2020-01-08 Bin Cheng <bin.li...@linux.alibaba.com> * tree-ssa-uninit.c (find_var_cmp_const): New function. (use_pred_not_overlap_with_undef_path_pred): Call above.
check-uninit_warning-with-vrinfo-20200108.txt
Description: Binary data
