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From: "lh_mouse at 126 dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/53929] [meta-bug] -masm=intel with global symbol Date: Thu, 04 May 2023 04:37:18 +0000 [thread overview] Message-ID: <bug-53929-4-j77ZQlM1jc@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-53929-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53929 --- Comment #13 from LIU Hao <lh_mouse at 126 dot com> --- dup notwithstanding, I think I had better copy my recommendation here for reference: This is how MSVC handles such names: (https://gcc.godbolt.org/z/TonjYaxqj) ``` static int* volatile rip; static unsigned int volatile eax; int get_value(void) { return rip[eax]; } ``` MSVC outputs: ``` get_value PROC ; COMDAT mov ecx, DWORD PTR eax mov rax, QWORD PTR rip mov eax, DWORD PTR [rax+rcx*4] ret 0 get_value ENDP ``` GCC outputs: ``` get_value: mov rdx, QWORD PTR rip[rip] mov eax, DWORD PTR eax[rip] mov eax, DWORD PTR [rdx+rax*4] ret ``` In the case of MSVC, `DWORD PTR eax` is unambiguously parsed as the label `eax` and `DWORD PTR [eax]` is unambiguously parsed as the register `eax`. The address of all labels are always relative to RIP, but it is implied, and brackets are not written explicitly. Maybe GCC can follow MSVC to omit the RIP register and brackets. The x86_64 memory reference syntax matches x86 with the only change in semantics of the immediate offset (for x86_64 it is relative to the next instruction, while for i686 it is absolute), but the opcode is the same.
next prev parent reply other threads:[~2023-05-04 4:37 UTC|newest] Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-11 15:39 [Bug c/53929] New: Bug in the use of Intel asm syntax when a global is named "and" louis.granboulan.developer at gmail dot com 2020-09-05 7:49 ` [Bug target/53929] " u1049321969 at caramail dot com 2020-09-06 18:42 ` asolokha at gmx dot com 2020-09-07 10:21 ` jakub at gcc dot gnu.org 2020-09-07 10:45 ` u1049321969 at caramail dot com 2020-09-07 10:54 ` jakub at gcc dot gnu.org 2020-10-26 10:17 ` jbeulich at suse dot com 2020-10-26 10:23 ` jbeulich at suse dot com 2020-12-31 15:06 ` [Bug target/53929] [meta-bug] -masm=intel with global symbol hjl.tools at gmail dot com 2020-12-31 15:07 ` hjl.tools at gmail dot com 2020-12-31 15:08 ` hjl.tools at gmail dot com 2020-12-31 15:08 ` hjl.tools at gmail dot com 2021-06-10 7:25 ` jbeulich at suse dot com 2023-05-04 4:20 ` pinskia at gcc dot gnu.org 2023-05-04 4:37 ` lh_mouse at 126 dot com [this message] 2023-05-04 6:21 ` jbeulich at suse dot com 2023-05-04 7:02 ` lh_mouse at 126 dot com 2023-05-04 7:15 ` jbeulich at suse dot com 2023-05-04 7:24 ` lh_mouse at 126 dot com 2023-05-04 13:14 ` lh_mouse at 126 dot com 2023-05-11 10:58 ` lh_mouse at 126 dot com 2023-05-11 11:35 ` jbeulich at suse dot com 2023-05-11 12:19 ` lh_mouse at 126 dot com 2023-05-11 14:30 ` jbeulich at suse dot com 2023-05-11 14:48 ` lh_mouse at 126 dot com 2024-01-18 5:38 ` lh_mouse at 126 dot com 2024-01-23 1:11 ` lh_mouse at 126 dot com 2024-01-24 2:16 ` lh_mouse at 126 dot com 2024-01-31 20:07 ` egallager at gcc dot gnu.org
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