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.
