Re: [PATCH v7 2/2] tty: add rpmsg driver

From: Joe Perches <joe@perches.com>
To: Jiri Slaby <jslaby@suse.cz>,
	Arnaud POULIQUEN <arnaud.pouliquen@st.com>,
	Ohad Ben-Cohen <ohad@wizery.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, linux-remoteproc@vger.kernel.org,
	Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suman Anna <s-anna@ti.com>,
	Fabien DESSENNE <fabien.dessenne@st.com>,
	linux-stm32@st-md-mailman.stormreply.com,
	xiang xiao <xiaoxiang781216@gmail.com>
Subject: Re: [PATCH v7 2/2] tty: add rpmsg driver
Date: Wed, 25 Mar 2020 17:01:57 -0700	[thread overview]
Message-ID: <f97d9dc54178e4344512bc7986265f101f4639c6.camel@perches.com> (raw)
In-Reply-To: <ec061c30-eace-1df9-fa7b-71a61e5710a2@suse.cz>

On Wed, 2020-03-25 at 14:31 +0100, Jiri Slaby wrote:
> The question was exactly about that: can a compiler optimize it to a
> bare number or will strlen call remain there?

$ cat str.c
#include <string.h>

int foo(void)
{
	return strlen("abc");
}

$ gcc -c -O2 str.c
$ objdump -d str.o
str.o:     file format elf64-x86-64

Disassembly of section .text:

0000000000000000 <foo>:
   0:	f3 0f 1e fa          	endbr64 
   4:	b8 03 00 00 00       	mov    $0x3,%eax
   9:	c3                   	retq   