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From: "christophe dot guillon at st dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/23756] Missed optimization for PIC code with internal visibility Date: Thu, 28 Jan 2010 14:55:00 -0000 [thread overview] Message-ID: <20100128145535.24939.qmail@sourceware.org> (raw) In-Reply-To: <bug-23756-7904@http.gcc.gnu.org/bugzilla/> ------- Comment #2 from christophe dot guillon at st dot com 2010-01-28 14:55 ------- This enhancement is still pending on gcc 4.4.3 on x86. A function declared internal sets the GOT pointer while it could be avoided in a callee-set-GOT model as on x86 ABI. By defintion an internal function can only be accessed through functions of the same module and thus, if the ABI forces the GOT pointer to be in ebx - which I think is the case -, it does not have to be rematerialized. See the original description also. Compile the attached internal.c file with: $ gcc -O3 -S -fpic internal.c Check the .s file: .type f, @function f: call __i686.get_pc_thunk.cx addl $_GLOBAL_OFFSET_TABLE_, %ecx The GOT pointer is materialized in ecx while it is guaranteed to be available in ebx as soon as f is actually internal. -- christophe dot guillon at st dot com changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |christophe dot guillon at st | |dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23756
next prev parent reply other threads:[~2010-01-28 14:55 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-23756-7904@http.gcc.gnu.org/bugzilla/> 2010-01-28 14:54 ` christophe dot guillon at st dot com 2010-01-28 14:55 ` christophe dot guillon at st dot com [this message] 2010-01-28 15:37 ` jakub at gcc dot gnu dot org 2010-01-28 16:20 ` christophe dot guillon at st dot com [not found] <bug-23756-4@http.gcc.gnu.org/bugzilla/> 2012-01-11 14:30 ` rguenth at gcc dot gnu.org 2005-09-06 20:41 [Bug c/23756] New: " guillaume dot melquiond at ens-lyon dot fr 2005-09-06 22:43 ` [Bug middle-end/23756] " pinskia at gcc dot gnu dot org
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