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Re: Type-based aliasing
- To: jfc at mit dot edu (John Carr)
- Subject: Re: Type-based aliasing
- From: Joern Rennecke <amylaar at cygnus dot co dot uk>
- Date: Fri, 12 Jun 1998 00:20:38 +0100 (BST)
- Cc: mark at markmitchell dot com, egcs at cygnus dot com
> 1. The alias code inherited from gcc2 looks at the form of an address
> to determine whether it is a fixed or variable address, and does
> optimizations based on this determination (the "struct/varying" test,
> a struct at a variable address can not alias a scalar at a fixed
> address). CSE can change a variable address to a fixed address,
> causing the alias check to falsely report that aliasing is not
> possible.
Maybe we should have another bit in MEMs that tells us when the MEM has
to be considered to be variable for alias analysis purposes.