Hi, Thanks for the review. > On 21 Dec 2025, at 8:37 am, Andrew Pinski <[email protected]> > wrote: > > External email: Use caution opening links or attachments > > > On Sun, Dec 14, 2025 at 1:18 PM Kugan Vivekanandarajah > <[email protected]> wrote: >> >> Hi, >> >> This patch shows up with AutoFDO but IMO this is not limited to AutoFDO. >> >> The bug is a stale Virtual SSA on calls to functions that have >> been marked const or pure. >> >> pure_const pass analyzes function rocksdb::y::y() and determines it has no >> side >> effects and marks it as const. >> >> At this point, existing call sites to y::y() in other functions still have: >> # .MEM_12 = VDEF <.MEM_11> rocksdb::y::y (&l, _9); >> >> Exact ICE is: >> cache/lru_cache.cc:921:1: error: virtual definition of statement not up to >> date >> # .MEM_12 = VDEF <.MEM_11> >> rocksdb::y::y (&l, _9); >> during GIMPLE pass: feedback_fnsplit >> dump file: lru_cache_reduced.ii.076t.feedback_fnsplit1 >> cache/lru_cache.cc:921:1: internal compiler error: verify_ssa failed >> 0x26f4073 internal_error(char const*, ...) >> ../../gcc-ro/gcc/diagnostic-global-context.cc:787 >> 0x16f91df verify_ssa(bool, bool) >> ../../gcc-ro/gcc/tree-ssa.cc:1203 >> 0x12f0643 execute_function_todo >> ../../gcc-ro/gcc/passes.cc:2104 >> 0x12f0beb execute_todo >> ../../gcc-ro/gcc/passes.cc:2149 >> >> >> In ipa-pure-const, we do execute_fixup_cfg only for the changed. IMO, we >> should call for all the functions that has this function called. Calling >> fixup for all also fixes this ICE. >> >> Later in feedback_fnsplit SSA verification fails. Added fixup >> after execute_feedback_split_functions also fixes this ICE. > This looks ok to me except I would add a comment on why you need the > fixup and no reason for the todo variable either: > > /* Update virtual SSA as some functions could have changed to be pure/const. > */ > retval |= execute_fixup_cfg (); > return retval;
Added the comments. Is this OK now? Thanks, Kugan > > Thanks, > Andrew > >> >> gcc/ChangeLog: >> >> 2025-12-08 Kugan Vivekanandarajah <[email protected]> >> >> * ipa-split.cc (execute_feedback_split_functions): Call >> * execute_fixup_cfg.
0001-Bug-gcov-profile-123019-V2-Fix-Virtual-SSA-ICE.patch
Description: 0001-Bug-gcov-profile-123019-V2-Fix-Virtual-SSA-ICE.patch
