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Re: [patch] for PR 18040


On Mon, 18 Oct 2004 14:33:03 +0200, Florian Weimer <fw@deneb.enyo.de> wrote:

> Unfortunately, var doesn't have to be addressable.

If var isn't addressable, there's no way to break up references into
multiple statements, because there's no way to get a handle on an
intermediate reference.  So it seems that we need to support
VIEW_CONVERT_EXPR (but not NOP_EXPR) inside references.

If var is addressable, uses of VIEW_CONVERT_EXPR can be broken up into
pointer casts.

My first draft of the gimplifier broke up references into multiple
statements, but I disabled that after I found that our RTL-level alias
analysis did better with a.b.c than with t1 = &a.b; t1->c.  Hopefully our
alias analysis has improved since then; as Daniel says, the optimizers work
better with smaller chunks.

Jason


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