Re: optimization/10076: Use of function call return value

["Gábor Lóki" <alga@rgai.hu>]

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The following reply was made to PR optimization/10076; it has been noted by GNATS.

From: =?ISO-8859-2?Q?G=E1bor_L=F3ki?= <alga@rgai.hu>
To: rth@gcc.gnu.org,  gcc-bugs@gcc.gnu.org,  gcc-prs@gcc.gnu.org, 
 nobody@gcc.gnu.org,  gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: optimization/10076: Use of function call return value
Date: Mon, 17 Mar 2003 14:54:05 +0100

 rth@gcc.gnu.org wrote:
 
 >Synopsis: Use of function call return value
 >
 >State-Changed-From-To: open->closed
 >State-Changed-By: rth
 >State-Changed-When: Sun Mar 16 09:29:48 2003
 >State-Changed-Why:
 >    Not really a bug.  You failed to return a value from foo1.
 >    Fix that, as you did in foo2, and everything clears up.
 >
 >http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10076
 >
 >
 >  
 >
     Ok, the source code was not correct, but the problem still remains.
 
     It doesn't matter if a retrun is put at the end of foo1 or not, gcc 
 produces the same problem.
 
     ( I subbmited a new PR: 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10122 
 )
 
          In example_1 there is an unnecessary "mov r2,r0" as I descibed 
 in PR.
         There is only one problem with this example. An opimization 
 algorithm changed the
         order of instructions. So the unnecessary "mov r0,#35" is placed 
 earlier than
         "str r2,[r3,#0]" (because of unnecessary "mov r2,r0", where r0 
 is dead).
 
         In example_2 there is another unnecessary "mov r3,r0". I don't 
 know the reason of this.
 
     I hope these examples will help what the problem is!
 
 Regards,
     Gábor Lóki