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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/108360] New: Dead Code Elimination Regression at -Os (trunk vs. 12.2.0) Date: Tue, 10 Jan 2023 13:10:43 +0000 [thread overview] Message-ID: <bug-108360-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108360 Bug ID: 108360 Summary: Dead Code Elimination Regression at -Os (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 54235 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54235&action=edit case.c as file cat case.c #321 static short b, c; unsigned char e; char f; void foo(); short(a)(short h, short i) { return h + i; } static short(d)(short h, int i) { return h >= 32 || h > 7 >> i ? h : h << i; } unsigned g(short h, short i) { return h + i; } int main() { short j, k = -1; c = a(0 >= b, k); f = c <= 0xD315BEF1; e = f << 4; j = d(e, 5); if (3 >= g(j == b, k)) foo(); b = 0; } `gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -Os` can not eliminate `foo` but `gcc-releases/gcc-12.2.0 -Os` can. `gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -Os -S -o /dev/stdout case.c` --------- OUTPUT --------- main: .LFB3: .cfi_startproc movw b(%rip), %cx xorl %edx, %edx testw %cx, %cx setle %dl movl %edx, %eax movb %dl, f(%rip) sall $4, %eax movb %al, e(%rip) movzbl %al, %eax testw %dx, %dx jne .L4 sall $5, %eax .L4: cmpw %ax, %cx jne .L7 pushq %rax .cfi_def_cfa_offset 16 xorl %eax, %eax call foo xorl %eax, %eax movw $0, b(%rip) popq %rdx .cfi_def_cfa_offset 8 ret .L7: movw $0, b(%rip) xorl %eax, %eax ret ---------- END OUTPUT --------- `gcc-releases/gcc-12.2.0 -Os -S -o /dev/stdout case.c` --------- OUTPUT --------- main: .LFB3: .cfi_startproc xorl %eax, %eax cmpw $0, b(%rip) movw $0, b(%rip) setle %al movb %al, f(%rip) sall $4, %eax movb %al, e(%rip) xorl %eax, %eax ret ---------- END OUTPUT --------- Bisects to: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=418b71c0d535bf91df78bad2e198c57934682eaa
next reply other threads:[~2023-01-10 13:10 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-10 13:10 yann at ywg dot ch [this message] 2023-01-10 14:48 ` [Bug tree-optimization/108360] [13 Regression] Dead Code Elimination Regression at -Os since r13-2048-g418b71c0d535bf marxin at gcc dot gnu.org 2023-01-10 17:00 ` jakub at gcc dot gnu.org 2023-01-10 17:32 ` jakub at gcc dot gnu.org 2023-01-10 17:45 ` jakub at gcc dot gnu.org 2023-01-10 19:18 ` amacleod at redhat dot com 2023-01-10 19:26 ` amacleod at redhat dot com 2023-01-10 19:28 ` amacleod at redhat dot com 2023-03-27 11:37 ` rguenth at gcc dot gnu.org 2023-04-08 14:37 ` law at gcc dot gnu.org 2023-04-26 6:57 ` [Bug tree-optimization/108360] [13/14 " rguenth at gcc dot gnu.org 2023-07-27 9:25 ` rguenth at gcc dot gnu.org 2023-08-07 8:53 ` pinskia at gcc dot gnu.org 2023-08-09 1:25 ` pinskia at gcc dot gnu.org 2024-05-21 9:13 ` [Bug tree-optimization/108360] [13/14/15 " jakub at gcc dot gnu.org
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