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From: "hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/50131] New: Optimize x = -1 with "or" for -O Date: Fri, 19 Aug 2011 20:58:00 -0000 [thread overview] Message-ID: <bug-50131-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50131 Bug #: 50131 Summary: Optimize x = -1 with "or" for -O Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target AssignedTo: unassigned@gcc.gnu.org ReportedBy: hjl.tools@gmail.com CC: ubizjak@gmail.com [hjl@gnu-6 rtm-1]$ cat x.c int foo1 () { return -1; } short foo2 () { return -1; } long long foo3 () { return -1; } [hjl@gnu-6 rtm-1]$ gcc -S -Os x.c [hjl@gnu-6 rtm-1]$ cat x.s .file "x.c" .text .globl foo1 .type foo1, @function foo1: .LFB0: .cfi_startproc orl $-1, %eax ret .cfi_endproc .LFE0: .size foo1, .-foo1 .globl foo2 .type foo2, @function foo2: .LFB1: .cfi_startproc orl $-1, %eax ret .cfi_endproc .LFE1: .size foo2, .-foo2 .globl foo3 .type foo3, @function foo3: .LFB2: .cfi_startproc orq $-1, %rax ret .cfi_endproc .LFE2: .size foo3, .-foo3 .ident "GCC: (GNU) 4.6.0 20110603 (Red Hat 4.6.0-10)" .section .note.GNU-stack,"",@progbits [hjl@gnu-6 rtm-1]$ gcc -S -O2 x.c [hjl@gnu-6 rtm-1]$ cat x.s .file "x.c" .text .p2align 4,,15 .globl foo1 .type foo1, @function foo1: .LFB0: .cfi_startproc movl $-1, %eax ret .cfi_endproc .LFE0: .size foo1, .-foo1 .p2align 4,,15 .globl foo2 .type foo2, @function foo2: .LFB1: .cfi_startproc movl $-1, %eax ret .cfi_endproc .LFE1: .size foo2, .-foo2 .p2align 4,,15 .globl foo3 .type foo3, @function foo3: .LFB2: .cfi_startproc movq $-1, %rax ret .cfi_endproc .LFE2: .size foo3, .-foo3 .ident "GCC: (GNU) 4.6.0 20110603 (Red Hat 4.6.0-10)" .section .note.GNU-stack,"",@progbits [hjl@gnu-6 rtm-1]$ I was expecting "or" for -O.
next reply other threads:[~2011-08-19 20:23 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-08-19 20:58 hjl.tools at gmail dot com [this message] 2011-08-19 21:19 ` [Bug target/50131] " hjl.tools at gmail dot com 2011-08-20 8:37 ` jakub at gcc dot gnu.org 2011-08-20 20:04 ` hjl.tools at gmail dot com 2011-08-21 9:20 ` rguenth at gcc dot gnu.org 2011-08-23 14:57 ` hjl.tools at gmail dot com 2021-12-15 1:34 ` pinskia at gcc dot gnu.org
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