https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105769
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |matz at gcc dot gnu.org --- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- And just statements that refer to those 3 variables that (incorrectly) share the stack slot + basic block boundaries. grep 'bias\|D.5698\|D.5681\|:' /tmp/00 struct struct void D.5698; struct map_t D.5681; struct vec bias; <bb 2> [local count: 1073741829]: _12 = (long unsigned int) &bias; bias ={v} {CLOBBER}; __ct_comp (&D.5698.__est, &D.5682); <bb 3> [local count: 1073741824]: MEM <vector(2) long unsigned int> [(void *)&D.5698 + 32B] = _21; <bb 4> [local count: 1073741824]: __ct_comp (_14, &D.5698.__est); <bb 5> [local count: 1073741824]: vect__16.52_79 = MEM <vector(2) long unsigned int> [(void *)&D.5698 + 32B]; __dt_base (&MEM[(struct function *)&D.5698].D.5235); D.5698 ={v} {CLOBBER}; D.5698 ={v} {CLOBBER(eol)}; MEM <char[16]> [(struct _Function_base *)&D.5681] = {}; MEM <vector(2) long unsigned int> [(bool (*<T72d>) (union _Any_data & {ref-all}, const union _Any_data & {ref-all}, _Manager_operation) *)&D.5681 + 16B] = _84; <bb 6> [count: 0]: <L5>: <bb 7> [count: 0]: <L4>: __dt_base (&MEM[(struct function *)&D.5698].D.5235); D.5698 ={v} {CLOBBER}; <bb 8> [local count: 429496]: <bb 9> [local count: 1073312328]: _19 (&D.5683.D.5217._M_functor, &D.5681); <bb 10> [local count: 1073312328]: __dt_base (&D.5681.D.5223); D.5681 ={v} {CLOBBER}; D.5681 ={v} {CLOBBER(eol)}; bias ={v} {CLOBBER(eol)}; <bb 11> [count: 0]: <L0>: __dt_base (&D.5681.D.5223); D.5681 ={v} {CLOBBER}; D.5681 ={v} {CLOBBER(eol)}; <bb 12> [count: 0]: <L2>: D.5698 ={v} {CLOBBER}; Now, perhaps the sharing of stack slot between D.5681 and D.5698 is fine, seems D.5698 is destructed before D.5681 is constructed: D.5698 ={v} {CLOBBER}; D.5698 ={v} {CLOBBER(eol)}; MEM <char[16]> [(struct _Function_base *)&D.5681] = {}; and D.5698 is later used just in EH block reachable only from earlier basic blocks or just as D.5698 ={v} {CLOBBER}; in the last EH bb. But the sharing of the stack slot in between bias and D.5698 looks wrong. What can be seen in the IL is: _12 = (long unsigned int) &bias; which has been hoisted before the bias ={v} {CLOBBER}; statement by the slp1 pass. From: ;; basic block 2, loop depth 0 ;; pred: ENTRY _3 = operator<< (&cout, "will do (ab)"); endl (_3); MEM[(struct vec *)&cov_jn] ={v} {CLOBBER}; bias ={v} {CLOBBER}; MEM[(struct function *)&D.5682] ={v} {CLOBBER}; MEM <char[16]> [(struct _Function_base *)&D.5682] = {}; MEM[(struct function *)&D.5682]._M_invoker = _M_invoke; MEM[(struct function *)&D.5682].D.5235._M_manager = _M_manager; __ct_comp (&D.5698.__est, &D.5682); ;; succ: 5 ;; 18 ;; basic block 5, loop depth 0 ;; pred: 2 D.5698.__cov = &cov_jn; D.5698.__bias = &bias; in dse4 to: ;; basic block 2, loop depth 0 ;; pred: ENTRY _12 = VIEW_CONVERT_EXPR<long unsigned int>(&bias); _15 = VIEW_CONVERT_EXPR<long unsigned int>(&cov_jn); _21 = {_15, _12}; _9 = VIEW_CONVERT_EXPR<long unsigned int>(_M_invoke); _10 = VIEW_CONVERT_EXPR<long unsigned int>(_M_manager); _8 = {_10, _9}; _3 = operator<< (&cout, "will do (ab)"); endl (_3); MEM[(struct vec *)&cov_jn] ={v} {CLOBBER}; bias ={v} {CLOBBER}; MEM[(struct function *)&D.5682] ={v} {CLOBBER}; MEM <char[16]> [(struct _Function_base *)&D.5682] = {}; MEM <vector(2) long unsigned int> [(bool (*<T72d>) (union _Any_data & {ref-all}, const union _Any_data & {ref-all}, _Manager_operation) *)&D.5682 + 16B] = _8; __ct_comp (&D.5698.__est, &D.5682); ;; succ: 5 ;; 18 ;; basic block 5, loop depth 0 ;; pred: 2 MEM <vector(2) long unsigned int> [(void *)&D.5698 + 32B] = _21; in slp1. Is that what is incorrect? And we should never hoist taking of addresses before a clobber on that var?