From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeffrey A Law <law@cygnus.com>
To: "Andrew Davies" <Andrew_Davies@Xmitel.com>
Cc: help-gcc@gnu.org
Subject: Re: Over optimisation 
Date: Thu, 30 Sep 1999 23:56:00 -0000
Message-ID: <11660.938097626@upchuck.cygnus.com>
References: <01bf05ce$5ca544c0$4f7fa890@us1.lincoln.msl.mitel.com>
X-SW-Source: 1999-09n/msg00359.html
Message-ID: <19990930235600.IXPFrGN0JO10J0ND0OKbvnjopTfYLCqEBFJBTmkZtZs@z>

  In message < 01bf05ce$5ca544c0$4f7fa890@us1.lincoln.msl.mitel.com >you write:
  > Hi,
  > 	I have a problem with the optimiser. When I compile the following test
  > loop:
  > 
  > do  {
  >     test = regbase->utx & 0x8000;
  >     }while(test == 0x0000);
  > 
  > 
  > It produces the following code:
  > 
  > 
  > send_byte:
  > 	link.w %a6,#0
  > 	move.w 16775430,%d0
  > 	and.w #32768,%d0
  > 	.even
  > .L9:
  > 	tst.w %d0
  > 	jbeq .L9
  > 
  > I think the optimiser is assuming the line inside the do while loop is
  > static and therefore removes it from the loop. As a result it gets stuck.
  > Anyone know how to solve this without turning the optimiser off? 
There's no way to tell without a complete bug report.  Please read the FAQ to 
learn how to properly send bug reports.
jeff