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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/108351] New: Dead Code Elimination Regression at -O3 (trunk vs. 12.2.0) Date: Tue, 10 Jan 2023 11:46:47 +0000 [thread overview] Message-ID: <bug-108351-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108351 Bug ID: 108351 Summary: Dead Code Elimination Regression at -O3 (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 54226 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54226&action=edit case file cat case.c #51 struct a { int b; } b; static short c = 7, d, e, a, k; int g; struct a h; int i; int j; void foo(); static struct a f(int l, unsigned short m) { a = e; k = d = j < i; if (m) return h; foo(); return b; } int main() { for (; g;) f(1, c); f(7, 7); f(9, 7); } `gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -O3` can not eliminate `foo` but `gcc-releases/gcc-12.2.0 -O3` can. `gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -O3 -S -o /dev/stdout case.c` --------- OUTPUT --------- f.isra.0: .LFB3: .cfi_startproc testw %di, %di je .L4 ret .p2align 4,,10 .p2align 3 .L4: xorl %eax, %eax jmp foo .cfi_endproc .LFE3: .size f.isra.0, .-f.isra.0 .section .text.startup,"ax",@progbits .p2align 4 .globl main .type main, @function main: .LFB1: .cfi_startproc movl g(%rip), %eax testl %eax, %eax je .L6 .L7: jmp .L7 .p2align 4,,10 .p2align 3 .L6: subq $8, %rsp .cfi_def_cfa_offset 16 movl $7, %edi call f.isra.0 movl $7, %edi call f.isra.0 xorl %eax, %eax addq $8, %rsp .cfi_def_cfa_offset 8 ret ---------- END OUTPUT --------- `gcc-releases/gcc-12.2.0 -O3 -S -o /dev/stdout case.c` --------- OUTPUT --------- main: .LFB1: .cfi_startproc movl g(%rip), %eax testl %eax, %eax je .L4 .L5: jmp .L5 .p2align 4,,10 .p2align 3 .L4: xorl %eax, %eax ret ---------- END OUTPUT --------- Bisects to: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=feeb0d68f1c7085199c3734e6517a3a4b58309ef
next reply other threads:[~2023-01-10 11:46 UTC|newest] Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-10 11:46 yann at ywg dot ch [this message] 2023-01-10 12:10 ` [Bug tree-optimization/108351] [13 Regression] " rguenth at gcc dot gnu.org 2023-01-10 14:41 ` [Bug tree-optimization/108351] [13 Regression] Dead Code Elimination Regression at -O3 since r13-4240-gfeeb0d68f1c708 marxin at gcc dot gnu.org 2023-01-10 22:48 ` pinskia at gcc dot gnu.org 2023-02-15 9:09 ` yinyuefengyi at gmail dot com 2023-02-15 9:15 ` yinyuefengyi at gmail dot com 2023-02-17 12:52 ` jamborm at gcc dot gnu.org 2023-04-08 14:38 ` law at gcc dot gnu.org 2023-04-26 6:57 ` [Bug tree-optimization/108351] [13/14 " rguenth at gcc dot gnu.org 2023-07-27 9:25 ` rguenth at gcc dot gnu.org 2023-11-24 12:43 ` sjames at gcc dot gnu.org 2023-11-24 14:56 ` yann at ywg dot ch 2023-11-24 15:47 ` jamborm at gcc dot gnu.org
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