https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110237
--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> --- (In reply to rguent...@suse.de from comment #5) > On Tue, 20 Jun 2023, crazylht at gmail dot com wrote: > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110237 > > > > --- Comment #4 from Hongtao.liu <crazylht at gmail dot com> --- > > (In reply to Richard Biener from comment #3) > > > This looks like the same issue as PR110309. We have > > > > > > (insn 38 35 39 3 (set (mem:V16SI (plus:DI (reg:DI 40 r12 [orig:90 _22 ] > > > [90]) > > > (const:DI (plus:DI (symbol_ref:DI ("b") [flags 0x2] > > > <var_decl 0x7ffff6e28d80 b>) > > > (const_int -4 [0xfffffffffffffffc])))) [1 MEM > > > <vector(16) int> [(int *)vectp_b.12_28]+0 S64 A32]) > > > (vec_merge:V16SI (reg:V16SI 20 xmm0 [118]) > > > (mem:V16SI (plus:DI (reg:DI 40 r12 [orig:90 _22 ] [90]) > > > (const:DI (plus:DI (symbol_ref:DI ("b") [flags 0x2] > > > <var_decl 0x7ffff6e28d80 b>) > > > (const_int -4 [0xfffffffffffffffc])))) [1 MEM > > > <vector(16) int> [(int *)vectp_b.12_28]+0 S64 A32]) > > > > > > so instead of a masked load we see a vec_merge with a (mem:V16SI ...) > > > based on the vectp_b.12_28 pointer that has full size but the load of b[1] > > > we try disambiguate against refers to int b[10] which is too small for > > > a load of 64 bytes so we disambiguate based on that. > > > > > > /* If the pointer based access is bigger than the variable they cannot > > alias. This is similar to the check below where we use TBAA to > > increase the size of the pointer based access based on the dynamic > > type of a containing object we can infer from it. */ > > poly_int64 dsize2; > > if (known_size_p (size1) --- should be unknown?? > > && poly_int_tree_p (DECL_SIZE (base2), &dsize2) > > && known_lt (dsize2, size1)) > > return false; > > > > Should we set MEM_SIZE_KNOWN_P to false for maskstore/maskload? > > It seems to me maxsize should be 64bytes, but real size should be unknown. > > Yes, you shouldn't have MEM_ATTRs that indicate the size is known. So it looks like a generic problem and better to be handled in expand_partial_{load, store}_optab_fn?
