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Date: Tue, 04 Dec 2001 10:00:00 -0000
From: Richard Henderson <rth@redhat.com>
To: Peter Barada <pbarada@mail.wm.sps.mot.com>
Cc: gcc@gcc.gnu.org
Subject: Re: How are case statements laid out?
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	Peter Barada <pbarada@mail.wm.sps.mot.com>, gcc@gcc.gnu.org
References: <Pine.BSF.4.42.0112031524050.66463-100000@naos.dbai.tuwien.ac.at> <200112031751.fB3HpxF15273@hyper.wm.sps.mot.com> <20011203145542.C7284@redhat.com> <200112041511.fB4FBMi25417@hyper.wm.sps.mot.com>
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In-Reply-To: <200112041511.fB4FBMi25417@hyper.wm.sps.mot.com>; from pbarada@mail.wm.sps.mot.com on Tue, Dec 04, 2001 at 10:11:22AM -0500
X-SW-Source: 2001-12/txt/msg00136.txt.bz2

On Tue, Dec 04, 2001 at 10:11:22AM -0500, Peter Barada wrote:
> Do you have an example?

Well, the easiest example is 

	gcc -O2 -S -fno-reorder-blocks z.c

	int foo(int i)
	{
	  if (i < 0)
	    {
	    label:
	      return -1;
	    }

	  switch (i)
	    {
	    case 0:
	      return 0;
	    case 1:
	      return 1;
	    case 2:
	      return 2;
	    case 3:
	      return 3;
	    case 4:
	      return 4;
	    case 5:
	      goto label;
	    }
	  return 6;
	}

as the goto will be folded into the table jump directly.

But apart from that -freorder-blocks will rearrange everything
as it sees fit.


r~