[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
-- What|Removed |Added Status|UNCONFIRMED |NEW Ever Confirmed||1 Last reconfirmed|-00-00 00:00:00 |2005-06-25 13:04:49 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From amylaar at gcc dot gnu dot org 2005-06-20 08:48 --- (In reply to comment #2) This was fixed by reverting the patch which caused this. Which patch was this? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-20 12:09 --- (In reply to comment #3) (In reply to comment #2) This was fixed by reverting the patch which caused this. Which patch was this? 2005-05-31 Pat Haugen [EMAIL PROTECTED] * loop.c (loop_invariant_p, valid_initial_value_p): Revert last change. The last change was: 2005-05-30 Pat Haugen [EMAIL PROTECTED] * loop.c (loop_invariant_p, valid_initial_value_p): Use regs_invalidated_by_call instead of call_used_regs. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From amylaar at gcc dot gnu dot org 2005-06-20 13:05 --- (In reply to comment #4) 2005-05-31 Pat Haugen [EMAIL PROTECTED] * loop.c (loop_invariant_p, valid_initial_value_p): Revert last change. The last change was: 2005-05-30 Pat Haugen [EMAIL PROTECTED] * loop.c (loop_invariant_p, valid_initial_value_p): Use regs_invalidated_by_call instead of call_used_regs. The failure that I analyzed involved killing stores to memory, not fixed registers. Therefore, the underlying problem has not been fixed, it has only become latent (again?). I don't think we should daclare a latent wrong-code bug as fixed. We might change the severity amd/or priority, though. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From amylaar at gcc dot gnu dot org 2005-06-20 13:21 --- P.S.: I realize now that the code in gcc/java/jcf-io.c is no longer miscompiled for i686-pc-linux-gnu because the memory addresses contain stack pointer references, and the stack pointer is a fixed register, i.e. call used, but not invalidated by a call. Hence with Pat Haugen's patch reversed, we falsely conclude that addresses of the stack locations are not loop invariant. Two wrongs don't make a right here, though. The wider context of the loop_invariant_p code is: case REG: if ((x == frame_pointer_rtx || x == hard_frame_pointer_rtx || x == arg_pointer_rtx || x == pic_offset_table_rtx) ! current_function_has_nonlocal_goto) return 1; if (LOOP_INFO (loop)-has_call REGNO (x) FIRST_PSEUDO_REGISTER call_used_regs[REGNO (x)]) return 0; I.e. if the libcall parameter values are addressed using an argument or frame pointer instead of directly via the stack pointer, invalid hoisting of the stores can still occur. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From amylaar at gcc dot gnu dot org 2005-06-21 05:37 --- The actual reason for the wrong-code generation has not been fixed. Moreover, AFAICS, on ACCUMULATE_OUTGOING_ARGS targets, the stack pointer is loop invariant unless current_function_calls_alloca, and pretending otherwise is an unnecessary pessimization. -- What|Removed |Added Status|RESOLVED|UNCONFIRMED Resolution|FIXED | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-06-19 14:06 --- This was fixed by reverting the patch which caused this. -- What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution||FIXED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
-- What|Removed |Added Keywords||patch http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
-- What|Removed |Added Summary|load_mems / |[4.1 Regression] load_mems / |replace_loop_mems bug causes|replace_loop_mems bug causes |miscompilation of jcf-io.c /|miscompilation of jcf-io.c / |SEGV while processing |SEGV while processing |java/lang/AbstractMethodErro|java/lang/AbstractMethodErro |r |r Target Milestone|--- |4.1.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
--- Additional Comments From amylaar at gcc dot gnu dot org 2005-05-31
20:56 ---
The problem would not arise if the call was neither const nor pure.
cselib_process_insn has this code:
if (CALL_P (insn))
{
for (i = 0; i FIRST_PSEUDO_REGISTER; i++)
if (call_used_regs[i]
|| (REG_VALUES (i) REG_VALUES (i)-elt
HARD_REGNO_CALL_PART_CLOBBERED (i,
GET_MODE (REG_VALUES (i)-elt-u.val_rtx
cselib_invalidate_regno (i, reg_raw_mode[i]);
if (! CONST_OR_PURE_CALL_P (insn))
cselib_invalidate_mem (callmem);
}
So, this explains why ordinary calls work.
There is code in load_mems to take the argument of calls into account, but
it requires CALL_INSN_FUNCTION_USAGE to be set. So a possible fix would make
sure that CALL_INSN_FUNCTION_USAGE is set correctly, at least for
CONST_OR_PURE_CALL_P functions.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
[Bug rtl-optimization/21848] [4.1 Regression] load_mems / replace_loop_mems bug causes miscompilation of jcf-io.c / SEGV while processing java/lang/AbstractMethodError
-- What|Removed |Added URL||http://gcc.gnu.org/ml/gcc- ||patches/2005- ||05/msg02946.html http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21848
