From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jim Wilson <wilson@cygnus.com>
To: Richard Henderson <rth@cygnus.com>
Cc: egcs@cygnus.com
Subject: Re: array reference optimization 
Date: Sun, 17 May 1998 17:58:00 -0000
Message-id: <199805172119.OAA03966@rtl.cygnus.com>
References: <19980513172502.54262@dot.cygnus.com>
X-SW-Source: 1998-05/msg00598.html

This looks OK to me.

However, I don't think that adding a new field to the tree types is
strictly necessary to solve this.  One could just as well do the divide
at the point we need it instead of saving it in all tree type nodes.

E.g. instead of what the old code does:
! 	  index = fold (build (MULT_EXPR, sbitsizetype, index,
! 			       convert (sbitsizetype,
! 					TYPE_SIZE (TREE_TYPE (exp)))));
	...
! 	offset = ...		   size_binop (FLOOR_DIV_EXPR, index,
! 					       size_int (BITS_PER_UNIT)));
which requires doing the multiply in bitsizetype, we could do the divide
first and then the multiple, something like this:
	oset = ... fold (build (MULT_EXPR, ssizetype, index,
			size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (...)
				    size_int (BITS_PER_UNIT))))
which keeps everything in range of sizetype.

Jim