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From: "gcc at pkh dot me" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/95189] New: memcmp being wrongly stripped (regression)
Date: Mon, 18 May 2020 13:56:37 +0000 [thread overview]
Message-ID: <bug-95189-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95189
Bug ID: 95189
Summary: memcmp being wrongly stripped (regression)
Product: gcc
Version: 10.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc at pkh dot me
Target Milestone: ---
Given the following C code:
% cat a.c
#include <string.h>
static const float z[1] = {0};
int f(float x) { return memcmp(&x, z, sizeof(x)); }
GCC 10 generates this on x86-64:
% gcc -Wall -O2 -c a.c && objdump -d -Mintel a.o
a.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <f>:
0: f3 0f 11 44 24 fc movss DWORD PTR [rsp-0x4],xmm0
6: 0f b6 44 24 fc movzx eax,BYTE PTR [rsp-0x4]
b: c3 ret
This doesn't happen if "= {0}" is removed from the z initialization (wtf?).
It also doesn't happen with -O1.
next reply other threads:[~2020-05-18 13:56 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-18 13:56 gcc at pkh dot me [this message]
2020-05-19 6:28 ` [Bug middle-end/95189] [10/11 Regression] memcmp being wrongly stripped like strcmp rguenth at gcc dot gnu.org
2020-05-23 21:01 ` jakub at gcc dot gnu.org
2020-05-23 21:17 ` jakub at gcc dot gnu.org
2020-05-24 20:10 ` msebor at gcc dot gnu.org
2020-06-09 13:38 ` gcc at pkh dot me
2020-06-09 23:53 ` msebor at gcc dot gnu.org
2020-06-24 21:24 ` msebor at gcc dot gnu.org
2020-07-01 0:25 ` msebor at gcc dot gnu.org
2020-07-01 14:46 ` msebor at gcc dot gnu.org
2020-07-13 15:50 ` jerryfromearth at gmail dot com
2020-07-20 18:09 ` cvs-commit at gcc dot gnu.org
2020-07-20 18:10 ` [Bug middle-end/95189] [10 " msebor at gcc dot gnu.org
2020-07-23 6:51 ` rguenth at gcc dot gnu.org
2020-08-16 20:26 ` [Bug middle-end/95189] [9/10 " pinskia at gcc dot gnu.org
2020-08-16 20:26 ` pinskia at gcc dot gnu.org
2020-09-03 22:37 ` amonakov at gcc dot gnu.org
2020-09-06 23:28 ` msebor at gcc dot gnu.org
2020-09-27 14:22 ` public at timruffing dot de
2020-10-05 23:41 ` luke-jr+gccbugs at utopios dot org
2020-10-06 5:47 ` amonakov at gcc dot gnu.org
2020-10-07 22:49 ` bugdal at aerifal dot cx
2020-10-08 4:31 ` luke-jr+gccbugs at utopios dot org
2020-10-08 18:38 ` cvs-commit at gcc dot gnu.org
2020-10-08 18:40 ` msebor at gcc dot gnu.org
2020-10-08 22:51 ` bugdal at aerifal dot cx
2020-10-09 0:12 ` luke-jr+gccbugs at utopios dot org
2020-10-09 2:26 ` bugdal at aerifal dot cx
2020-10-09 13:09 ` luke-jr+gccbugs at utopios dot org
2021-01-02 5:05 ` davmac at davmac dot org
2021-06-01 8:17 ` rguenth at gcc dot gnu.org
2021-06-24 1:13 ` bugdal at aerifal dot cx
2021-06-24 6:29 ` [Bug middle-end/95189] [9 " rguenth at gcc dot gnu.org
2022-03-17 19:47 ` msebor at gcc dot gnu.org
2022-05-27 8:54 ` rguenth at gcc dot gnu.org
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