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Re: Your change to function.c
- To: law at cygnus dot com, Richard Henderson <rth at cygnus dot com>
- Subject: Re: Your change to function.c
- From: Richard Henderson <rth at cygnus dot com>
- Date: Mon, 5 Oct 1998 00:24:38 -0700
- Cc: mark at markmitchell dot com, egcs-patches at cygnus dot com
- References: <19981005000420.A13018@dot.cygnus.com> <4399.907571095@hurl.cygnus.com>
- Reply-To: Richard Henderson <rth at cygnus dot com>
On Mon, Oct 05, 1998 at 01:04:55AM -0600, Jeffrey A Law wrote:
> But should we have had subregs of those float things in the first place?
I don't see why not.
It's particularly helpful for situations like the test in question,
where the fp value is initially in memory, we do some bit twiddling,
and then we finish off with some actual fp operation.
Doing otherwise results in an initial memory-to-memory copy that's
just completely wasteful.
> Remember, not all subregging is safe, particularly when dealing with
> floating point modes.
Well, do you think this isn't? I think it is, but am willing to be
convinced. I suppose there could be aliasing issues, though I'm not
sure how go about forceing one to be sure.
It's slightly annoying that I committed the change a few minutes before
your responce, based on a note from Mark.
r~