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From: "yann at ywg dot ch" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/108355] New: Dead Code Elimination Regression at -O2 (trunk vs. 12.2.0) Date: Tue, 10 Jan 2023 12:46:29 +0000 [thread overview] Message-ID: <bug-108355-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108355 Bug ID: 108355 Summary: Dead Code Elimination Regression at -O2 (trunk vs. 12.2.0) Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: yann at ywg dot ch Target Milestone: --- Created attachment 54230 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54230&action=edit presented code as file cat case.c #551 int a; int *b = &a; int **c = &b; int d; void bar25_(void); void foo(void); int main() { int e[][1] = {0, 0, 0, 0, 0, 1}; for (;;) { bar25_(); if (e[5][a]) break; e[a][0] = 0; foo(); } *c = &d; } `gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -O2` can not eliminate `foo` but `gcc-releases/gcc-12.2.0 -O2` can. `gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -O2 -S -o /dev/stdout case.c` --------- OUTPUT --------- main: .LFB0: .cfi_startproc subq $40, %rsp .cfi_def_cfa_offset 48 movl $1, 20(%rsp) jmp .L3 .p2align 4,,10 .p2align 3 .L6: movl $0, (%rsp,%rax,4) call foo .L3: call bar25_ movslq a(%rip), %rax movl 20(%rsp,%rax,4), %edx testl %edx, %edx je .L6 movq c(%rip), %rax movq $d, (%rax) xorl %eax, %eax addq $40, %rsp .cfi_def_cfa_offset 8 ret ---------- END OUTPUT --------- `gcc-releases/gcc-12.2.0 -O2 -S -o /dev/stdout case.c` --------- OUTPUT --------- main: .LFB0: .cfi_startproc subq $8, %rsp .cfi_def_cfa_offset 16 call bar25_ movq c(%rip), %rax movq $d, (%rax) xorl %eax, %eax addq $8, %rsp .cfi_def_cfa_offset 8 ret ---------- END OUTPUT --------- Bisects to: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=9baee6181b4e427e0b5ba417e51424c15858dce7
next reply other threads:[~2023-01-10 12:46 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-10 12:46 yann at ywg dot ch [this message] 2023-01-10 14:45 ` [Bug tree-optimization/108355] [13 Regression] Dead Code Elimination Regression at -O2 since r13-2772-g9baee6181b4e42 marxin at gcc dot gnu.org 2023-01-10 16:20 ` rguenth at gcc dot gnu.org 2023-01-11 14:46 ` rguenth at gcc dot gnu.org 2023-02-14 21:45 ` cvs-commit at gcc dot gnu.org 2023-02-14 21:48 ` pinskia at gcc dot gnu.org 2023-04-08 14:38 ` law at gcc dot gnu.org 2023-04-26 6:57 ` [Bug tree-optimization/108355] [13/14 " rguenth at gcc dot gnu.org 2023-07-27 9:25 ` rguenth at gcc dot gnu.org 2024-02-12 13:37 ` cvs-commit at gcc dot gnu.org 2024-02-28 14:03 ` [Bug tree-optimization/108355] [13 " cvs-commit at gcc dot gnu.org 2024-02-28 14:04 ` [Bug tree-optimization/108355] [13/14 " rguenth at gcc dot gnu.org 2024-03-08 1:07 ` hp at gcc dot gnu.org 2024-03-08 1:13 ` pinskia at gcc dot gnu.org 2024-03-08 7:25 ` rguenth at gcc dot gnu.org 2024-03-08 7:28 ` cvs-commit at gcc dot gnu.org 2024-05-21 9:13 ` [Bug tree-optimization/108355] [13/14/15 " jakub at gcc dot gnu.org
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